update to 2024.01.31

Jenkinsfile

@@ -19,7 +19,7 @@ pipeline {
                         classPattern: '**/build/classes/java/main',
                         sourcePattern: '**/src/main'
                     )
-                    javadoc javadocDir: "build/docs/javadoc", keepAll: true
+                    //javadoc javadocDir: "build/docs/javadoc", keepAll: true
                     archiveArtifacts artifacts: '**/build/libs/*.jar',
                                      allowEmptyArchive: false,
                                      fingerprint: true,

build.gradle

@@ -17,12 +17,11 @@ allprojects {
         }
         mavenCentral()
     }
-
     pluginManager.withPlugin('java-library') {
 
         java {
             toolchain {
-                languageVersion = JavaLanguageVersion.of(17)
+                languageVersion = JavaLanguageVersion.of(21)
                 vendor = JvmVendorSpec.GRAAL_VM
             }
         }
@@ -63,7 +62,7 @@ allprojects {
 
         pluginManager.withPlugin('java-library') {
             java {
-                withJavadocJar()
+//                withJavadocJar()
                 withSourcesJar()
             }
         }

gradle.properties

@@ -1,3 +1,3 @@
-jwo.version = 2024.01.29
+jwo.version = 2024.01.31
 lys.version = 2024.01.29
 guice.version = 5.0.1

jmath-benchmark/build.gradle

@@ -16,7 +16,7 @@ dependencies {
     implementation project(':jmath')
 }
 
-envelopeJar {
+application {
     mainClass = 'net.woggioni.jmath.benchmark.Main'
 }
 

jmath-benchmark/native-image/resource-config.json

@@ -1,5 +1,7 @@
 {
   "resources":{
-  "includes":[]},
+  "includes":[{
+    "pattern":"\\QMETA-INF/services/java.time.zone.ZoneRulesProvider\\E"
+  }]},
   "bundles":[]
 }

jmath-benchmark/src/main/java/net/woggioni/jmath/benchmark/Main.java

@@ -24,10 +24,15 @@ public class Main {
         Matrix<Rational> mtx  = Matrix.of(numericTypeFactory, size, size, init);
         Matrix<Rational> lu = mtx.clone();
         Matrix.Pivot pivot = lu.lup();
-        IntFunction<Rational> initVector = (i) -> Rational.of(rnd.nextInt(0, size), size);
+        for(int i = 0; i < size; i++) {
-        Vector<Rational> b = Vector.of(numericTypeFactory, size, initVector);
+            IntFunction<Rational> initVector = (j) -> Rational.of(rnd.nextInt(0, size), size);
-        Vector<Rational> x = lu.luSolve(b, pivot);
+            Vector<Rational> b = Vector.of(numericTypeFactory, size, initVector);
-        Vector<Rational> error  = mtx.mmul(x).sub(b);
+            Vector<Rational> x = lu.luSolve(b, pivot);
-        System.out.println(error.norm());
+            Vector<Rational> error = mtx.mmul(x).sub(b);
+            Rational norm = error.norm();
+            if(norm.compareTo(Rational.ZERO) != 0) {
+                throw new RuntimeException(String.format("Error is %s", norm));
+            }
+        }
     }
 }

src/main/java/net/woggioni/jwo/ChannerWriter.java

@@ -0,0 +1,36 @@
+package net.woggioni.jwo;
+
+import lombok.RequiredArgsConstructor;
+
+import java.io.IOException;
+import java.io.Writer;
+import java.nio.ByteBuffer;
+import java.nio.channels.WritableByteChannel;
+import java.nio.charset.Charset;
+
+@RequiredArgsConstructor
+public class ChannerWriter extends Writer {
+
+    private final WritableByteChannel ch;
+
+    private final Charset charset;
+
+
+    @Override
+    public void write(char[] cbuf, int off, int len) throws IOException {
+        write(new String(cbuf, off, len));
+    }
+
+    @Override
+    public void write(String str) throws IOException {
+        ch.write(ByteBuffer.wrap(str.getBytes(charset)));
+    }
+
+    @Override
+    public void flush() {}
+
+    @Override
+    public void close() throws IOException {
+        ch.close();
+    }
+}

src/main/java/net/woggioni/jwo/CollectionUtils.java

@@ -25,6 +25,10 @@ import java.util.stream.Stream;
 
 public class CollectionUtils {
 
+    public enum MapMergeStrategy {
+        THROW, REPLACE, KEEP
+    }
+
     @SafeVarargs
     public static <T> ArrayList<T> newArrayList(T... args) {
         return new ArrayList<>(Arrays.asList(args));
@@ -125,18 +129,43 @@ public class CollectionUtils {
         };
     }
 
-    public static <T> T throwingMerger(T v1, T v2) {
+    private static <T> BinaryOperator<T> throwingMerger() {
-        throw new IllegalStateException(String.format("Duplicate key %s", v1));
+        return (v1, v2) -> {
+            throw new IllegalStateException(String.format("Duplicate key %s", v1));
+        };
+    }
+    private static <T> BinaryOperator<T> updatingMerger() {
+        return (v1, v2) -> v2;
     }
 
-    public static <T> T oldValueMerger(T oldValue, T newValue) {
+    private static <T> BinaryOperator<T> conservativeMerger() {
-        return oldValue;
+        return (v1, v2) -> v1;
     }
 
-    public static <T> T newValueMerger(T oldValue, T newValue) {
+    private static <T> BinaryOperator<T> getMerger(MapMergeStrategy mapMergeStrategy) {
-        return newValue;
+        BinaryOperator<T> result;
+        switch (mapMergeStrategy) {
+            case KEEP:
+                result = conservativeMerger();
+                break;
+            case THROW:
+                result = throwingMerger();
+                break;
+            case REPLACE:
+                result = updatingMerger();
+                break;
+            default:
+                throw new NullPointerException();
+        }
+        return result;
     }
 
+    public static <T, K, V> Collector<T, ?, Map<K, V>> toUnmodifiableHashMap(
+        Function<T, K> keyExtractor,
+        Function<T, V> valueExtractor,
+        MapMergeStrategy mapMergeStrategy) {
+        return toUnmodifiableMap(HashMap::new, keyExtractor, valueExtractor, mapMergeStrategy);
+    }
     public static <T, K, V> Collector<T, ?, Map<K, V>> toUnmodifiableHashMap(
             Function<T, K> keyExtractor,
             Function<T, V> valueExtractor) {
@@ -149,6 +178,19 @@ public class CollectionUtils {
         return toUnmodifiableNavigableMap(TreeMap::new, keyExtractor, valueExtractor);
     }
 
+    public static <T, K, V> Collector<T, ?, NavigableMap<K, V>> toUnmodifiableTreeMap(
+        Function<T, K> keyExtractor,
+        Function<T, V> valueExtractor,
+        MapMergeStrategy mapMergeStrategy) {
+        return toUnmodifiableNavigableMap(TreeMap::new, keyExtractor, valueExtractor, mapMergeStrategy);
+    }
+    public static <T, K, V> Collector<T, ?, NavigableMap<K, V>> toUnmodifiableTreeMap(
+        Function<T, K> keyExtractor,
+        Function<T, V> valueExtractor,
+        Comparator<K> comparator,
+        MapMergeStrategy mapMergeStrategy) {
+        return toUnmodifiableNavigableMap(() -> new TreeMap<>(comparator), keyExtractor, valueExtractor, mapMergeStrategy);
+    }
     public static <T, K, V> Collector<T, ?, NavigableMap<K, V>> toUnmodifiableTreeMap(
             Function<T, K> keyExtractor,
             Function<T, V> valueExtractor,
@@ -156,6 +198,12 @@ public class CollectionUtils {
         return toUnmodifiableNavigableMap(() -> new TreeMap<>(comparator), keyExtractor, valueExtractor);
     }
 
+    public static <T, K, V> Collector<T, ?, NavigableMap<K, V>> toTreeMap(
+        Function<T, K> keyExtractor,
+        Function<T, V> valueExtractor,
+        MapMergeStrategy mapMergeStrategy) {
+        return toNavigableMap(TreeMap::new, keyExtractor, valueExtractor, mapMergeStrategy);
+    }
     public static <T, K, V> Collector<T, ?, NavigableMap<K, V>> toTreeMap(
             Function<T, K> keyExtractor,
             Function<T, V> valueExtractor) {
@@ -169,6 +217,14 @@ public class CollectionUtils {
         return toNavigableMap(() -> new TreeMap<>(comparator), keyExtractor, valueExtractor);
     }
 
+    public static <T, K, V> Collector<T, ?, NavigableMap<K, V>> toTreeMap(
+        Function<T, K> keyExtractor,
+        Function<T, V> valueExtractor,
+        Comparator<K> comparator,
+        MapMergeStrategy mapMergeStrategy) {
+        return toNavigableMap(() -> new TreeMap<>(comparator), keyExtractor, valueExtractor, mapMergeStrategy);
+    }
+
     public static <T, K, V, MAP_TYPE extends NavigableMap<K, V>> Collector<T, ?, MAP_TYPE> toNavigableMap(
         Supplier<MAP_TYPE> constructor,
         Function<T, K> keyExtractor,
@@ -177,7 +233,7 @@ public class CollectionUtils {
             constructor,
             keyExtractor,
             valueExtractor,
-            CollectionUtils::throwingMerger
+            MapMergeStrategy.THROW
         );
     }
 
@@ -185,7 +241,8 @@ public class CollectionUtils {
             Supplier<MAP_TYPE> constructor,
             Function<T, K> keyExtractor,
             Function<T, V> valueExtractor,
-            BinaryOperator<V> valueMerger) {
+            MapMergeStrategy mapMergeStrategy) {
+        BinaryOperator<V> valueMerger = getMerger(mapMergeStrategy);
         BiConsumer<MAP_TYPE, T> accumulator = (map, streamElement) -> {
             map.merge(keyExtractor.apply(streamElement), valueExtractor.apply(streamElement),
                 valueMerger
@@ -202,14 +259,15 @@ public class CollectionUtils {
         Supplier<Map<K, V>> constructor,
         Function<T, K> keyExtractor,
         Function<T, V> valueExtractor) {
-        return toMap(constructor, keyExtractor, valueExtractor, CollectionUtils::throwingMerger);
+        return toMap(constructor, keyExtractor, valueExtractor, MapMergeStrategy.THROW);
     }
 
     public static <T, K, V> Collector<T, ?, Map<K, V>> toMap(
             Supplier<Map<K, V>> constructor,
             Function<T, K> keyExtractor,
             Function<T, V> valueExtractor,
-            BinaryOperator<V> valueMerger) {
+            MapMergeStrategy mapMergeStrategy) {
+        BinaryOperator<V> valueMerger = getMerger(mapMergeStrategy);
         BiConsumer<Map<K, V>, T> accumulator = (map, streamElement) -> {
             map.merge(keyExtractor.apply(streamElement), valueExtractor.apply(streamElement),
                 valueMerger
@@ -226,13 +284,14 @@ public class CollectionUtils {
         Supplier<Map<K, V>> constructor,
         Function<T, K> keyExtractor,
         Function<T, V> valueExtractor) {
-        return toUnmodifiableMap(constructor, keyExtractor, valueExtractor, CollectionUtils::throwingMerger);
+        return toUnmodifiableMap(constructor, keyExtractor, valueExtractor, MapMergeStrategy.THROW);
     }
     public static <T, K, V> Collector<T, ?, Map<K, V>> toUnmodifiableMap(
             Supplier<Map<K, V>> constructor,
             Function<T, K> keyExtractor,
             Function<T, V> valueExtractor,
-            BinaryOperator<V> valueMerger) {
+            MapMergeStrategy mapMergeStrategy) {
+        BinaryOperator<V> valueMerger = getMerger(mapMergeStrategy);
         BiConsumer<Map<K, V>, T> accumulator = (map, streamElement) -> {
             map.merge(keyExtractor.apply(streamElement),
                 valueExtractor.apply(streamElement),
@@ -251,8 +310,9 @@ public class CollectionUtils {
         Supplier<NavigableMap<K, V>> constructor,
         Function<T, K> keyExtractor,
         Function<T, V> valueExtractor,
-        BinaryOperator<V> valueMerger
+        MapMergeStrategy mapMergeStrategy
     ) {
+        BinaryOperator<V> valueMerger = getMerger(mapMergeStrategy);
         BiConsumer<NavigableMap<K, V>, T> accumulator = (map, streamElement) -> {
             map.merge(
                 keyExtractor.apply(streamElement),
@@ -271,7 +331,7 @@ public class CollectionUtils {
             Supplier<NavigableMap<K, V>> constructor,
             Function<T, K> keyExtractor,
             Function<T, V> valueExtractor) {
-        return toUnmodifiableNavigableMap(constructor, keyExtractor, valueExtractor, CollectionUtils::throwingMerger);
+        return toUnmodifiableNavigableMap(constructor, keyExtractor, valueExtractor, MapMergeStrategy.THROW);
     }
     public static <K, V, U> Stream<Map.Entry<K, U>> mapValues(Map<K, V> map, Fun<V, U> xform) {
         return map

src/main/java/net/woggioni/jwo/JWO.java

@@ -4,6 +4,7 @@ import lombok.SneakyThrows;
 import lombok.extern.slf4j.Slf4j;
 import net.woggioni.jwo.exception.ChildProcessException;
 import net.woggioni.jwo.internal.CharFilterReader;
+import org.slf4j.Logger;
 
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.HttpsURLConnection;
@@ -12,9 +13,7 @@ import javax.net.ssl.SSLSession;
 import javax.net.ssl.SSLSocketFactory;
 import javax.net.ssl.TrustManager;
 import javax.net.ssl.X509TrustManager;
-import java.io.BufferedInputStream;
 import java.io.File;
-import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 import java.io.InputStream;
@@ -25,6 +24,8 @@ import java.io.Reader;
 import java.io.StringWriter;
 import java.io.Writer;
 import java.lang.reflect.Constructor;
+import java.net.URL;
+import java.net.URLStreamHandlerFactory;
 import java.nio.channels.Channels;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -35,6 +36,8 @@ import java.nio.file.attribute.FileAttribute;
 import java.security.DigestOutputStream;
 import java.security.MessageDigest;
 import java.security.cert.X509Certificate;
+import java.util.AbstractMap;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Comparator;
 import java.util.EnumSet;
@@ -69,6 +72,10 @@ import java.util.zip.ZipOutputStream;
 
 @Slf4j
 public class JWO {
+
+    private static final String PROTOCOL_HANDLER = "java.protocol.handler.pkgs";
+    private static final String HANDLERS_PACKAGE = "net.woggioni.jwo.url";
+
     public static <T> Stream<T> iterable2Stream(Iterable<T> iterable) {
         return StreamSupport.stream(iterable.spliterator(), false);
     }
@@ -1004,4 +1011,100 @@ public class JWO {
         }
         public void run() { executor.execute(action); }
     }
+
+    public static String toUnixPath(Path path) {
+        String result;
+        if (OS.isUnix) {
+            result = path.toString();
+        } else {
+            result = (path.isAbsolute() ? "/" : "") +
+                iterable2Stream(path)
+                    .map(Path::toString)
+                    .collect(Collectors.joining("/"));
+        }
+        return result;
+    }
+
+    public static void registerUrlProtocolHandler() {
+        String handlers = System.getProperty(PROTOCOL_HANDLER, "");
+        System.setProperty(PROTOCOL_HANDLER,
+            ((handlers == null || handlers.isEmpty()) ? HANDLERS_PACKAGE : handlers + "|" + HANDLERS_PACKAGE));
+        resetCachedUrlHandlers();
+    }
+
+    /**
+     * Reset any cached handlers just in case a jar protocol has already been used. We
+     * reset the handler by trying to set a null {@link URLStreamHandlerFactory} which
+     * should have no effect other than clearing the handlers cache.
+     */
+    private static void resetCachedUrlHandlers() {
+        try {
+            URL.setURLStreamHandlerFactory(null);
+        } catch (Error ex) {
+            // Ignore
+        }
+    }
+
+    @SneakyThrows
+    public static void deletePath(Logger log, Path path) {
+        if (Files.exists(path)) {
+            if (log.isInfoEnabled()) {
+                log.info("Wiping '{}'", path);
+            }
+            deletePath(path);
+        }
+    }
+
+    public static <T, U extends T> U downCast(T param) {
+        return (U) param;
+    }
+
+    public static <T extends U, U> U upCast(T param) {
+        return param;
+    }
+
+    public static <T, U extends T> Optional<U> asInstance(T param, Class<U> cls) {
+        return Optional.ofNullable(param)
+            .filter(cls::isInstance)
+            .map(cls::cast);
+    }
+
+    public static <K, V, U> Stream<Map.Entry<K, U>> mapValues(Map<K, V> map, Fun<V, U> xform) {
+        return map
+            .entrySet()
+            .stream()
+            .map(entry -> new AbstractMap.SimpleEntry<>(entry.getKey(), xform.apply(entry.getValue())));
+    }
+
+    @SneakyThrows
+    public static Process startJavaProcess(
+        Logger log,
+        Path javaHome,
+        List<String> args,
+        Path cwd,
+        Map<String, String> env) {
+        Path javaExecutable = javaHome.resolve("bin/java" + (OS.isWindows ? ".exe" : ""));
+        ProcessBuilder pb = new ProcessBuilder();
+        List<String> cmd = new ArrayList<>();
+        cmd.add(javaExecutable.toString());
+        cmd.addAll(args);
+        pb.command(cmd);
+        pb.inheritIO();
+        pb.directory(cwd.toFile());
+        pb.environment().putAll(env);
+        if (log.isTraceEnabled()) {
+            String cmdLineListString = '[' + cmd.stream().map(s -> '\'' + s + '\'').collect(Collectors.joining(", ")) + ']';
+            log.trace("Starting child java process with command line: {}", cmdLineListString);
+        }
+        return pb.start();
+    }
+
+    public static <T, U> U let(T object, Function<T, U> cb) {
+        return cb.apply(object);
+    }
+
+    public static <T> T also(T object, Consumer<T> cb) {
+        cb.accept(object);
+        return object;
+    }
 }

src/main/java/net/woggioni/jwo/LazyOptional.java

@@ -0,0 +1,77 @@
+package net.woggioni.jwo;
+
+
+import lombok.RequiredArgsConstructor;
+
+import java.util.Optional;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.function.Supplier;
+
+@RequiredArgsConstructor
+public class LazyOptional<T> {
+    private static final LazyOptional empty = new LazyOptional<>(() -> null);
+
+    private final Supplier<T> producer;
+    private final MutableTuple2<T, Boolean> instance = MutableTuple2.newInstance(null, false);
+
+    public static <U> LazyOptional<U> of(Supplier<U> producer) {
+        return new LazyOptional<>(producer);
+    }
+
+    public static <U> LazyOptional<U> or(LazyOptional<U>... opts) {
+        return LazyOptional.of(() -> {
+                for (LazyOptional<U> opt : opts) {
+                    U value = opt.get();
+                    if (value != null) return value;
+                }
+                return null;
+            }
+        );
+    }
+
+    public static <U> LazyOptional<U> empty() {
+        return (LazyOptional<U>) empty;
+    }
+
+    public <U> LazyOptional<U> map(Function<T, U> mapping) {
+        return LazyOptional.of(() -> {
+            T prevValue = producer.get();
+            if (prevValue == null) return null;
+            else return mapping.apply(prevValue);
+        });
+    }
+
+    public LazyOptional<T> filter(Predicate<T> predicate) {
+        return LazyOptional.of(() -> {
+            T prevValue = producer.get();
+            if (predicate.test(prevValue)) return prevValue;
+            else return null;
+        });
+    }
+
+    public T get() {
+        if (instance.get_2()) return instance.get_1();
+        synchronized (instance) {
+            if (instance.get_2()) return instance.get_1();
+            else {
+                T value = producer.get();
+                instance.set_1(value);
+                instance.set_2(true);
+                return value;
+            }
+        }
+    }
+
+    public <U> LazyOptional<U> flatMap(Function<T, LazyOptional<U>> mapping) {
+        return new LazyOptional<>(() -> {
+            T prevValue = producer.get();
+            if (prevValue == null) return null;
+            else return mapping.apply(prevValue).get();
+        });
+    }
+
+    public Optional<T> getOptional() {
+        return Optional.ofNullable(get());
+    }
+}

src/main/java/net/woggioni/jwo/LazyValue.java

@@ -1,10 +1,12 @@
 package net.woggioni.jwo;
 
+import lombok.RequiredArgsConstructor;
 import net.woggioni.jwo.internal.SynchronizedLazyValue;
 import net.woggioni.jwo.internal.UnsynchronizedLazyValue;
 
 import java.util.Optional;
 import java.util.function.BiFunction;
+import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
@@ -30,19 +32,22 @@ public interface LazyValue<T> {
      */
     Optional<T> close();
 
-
+    static <T> LazyValue<T> of(Supplier<T> supplier, ThreadSafetyMode locking, Consumer<T> finalizer) {
-    static <T> LazyValue<T> of(Supplier<T> supplier, ThreadSafetyMode locking) {
         LazyValue<T> result;
         switch (locking) {
             case SYNCHRONIZED:
-                result = new SynchronizedLazyValue<>(supplier);
+                result = new SynchronizedLazyValue<>(supplier, finalizer);
                 break;
             case NONE:
-                result = new UnsynchronizedLazyValue<>(supplier);
+                result = new UnsynchronizedLazyValue<>(supplier, finalizer);
                 break;
             default:
                 throw new RuntimeException("This should never happen");
         }
         return result;
     }
+
+    static <T> LazyValue<T> of(Supplier<T> supplier, ThreadSafetyMode locking) {
+        return of(supplier, locking, null);
+    }
 }

src/main/java/net/woggioni/jwo/LockFile.java

@@ -1,39 +1,40 @@
 package net.woggioni.jwo;
 
-import lombok.SneakyThrows;
+import java.io.Closeable;
-
+import java.io.IOException;
-import java.io.RandomAccessFile;
+import java.nio.channels.FileChannel;
 import java.nio.channels.FileLock;
-import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.EnumSet;
 
-public class LockFile implements AutoCloseable {
+public class LockFile implements Closeable {
 
-    private final Path path;
     private final FileLock lock;
-    private final RandomAccessFile randomAccessFile;
 
-    public LockFile(Path path) {
+    private static FileChannel openFileChannel(Path path) throws IOException {
-        this(path, false);
+        Files.createDirectories(path.getParent());
+        return FileChannel.open(path, EnumSet.of(StandardOpenOption.CREATE, StandardOpenOption.READ, StandardOpenOption.WRITE));
     }
 
-    @SneakyThrows
+    public static LockFile acquire(Path path, boolean shared) throws IOException {
-    public LockFile(Path path, boolean shared) {
+        FileChannel channel = openFileChannel(path);
-        this.path = path;
+        return new LockFile(channel.lock(0L, Long.MAX_VALUE, shared));
-        try {
+    }
-            Files.createDirectories(path.getParent());
+
-            Files.createFile(path);
+    public static LockFile tryAcquire(Path path, boolean shared) throws IOException {
-        } catch(FileAlreadyExistsException faee) {
+        FileChannel channel = openFileChannel(path);
-        }
+        FileLock lock = channel.tryLock(0L, Long.MAX_VALUE, shared);
-        randomAccessFile = new RandomAccessFile(path.toFile(), "rw");
+        return (lock != null) ? new LockFile(lock) : null;
-        lock = randomAccessFile.getChannel().lock(0L, Long.MAX_VALUE, shared);
+    }
+
+    private LockFile(FileLock lock) {
+        this.lock = lock;
     }
 
     @Override
-    @SneakyThrows
+    public void close() throws IOException {
-    public void close() {
+        lock.channel().close();
-        lock.release();
-        randomAccessFile.close();
     }
 }

src/main/java/net/woggioni/jwo/MapBuilder.java

@@ -5,6 +5,7 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
+import java.util.stream.Stream;
 
 public class MapBuilder<K,V> {
     private final List<Map.Entry<K, V>> entries = new ArrayList<>();
@@ -22,7 +23,15 @@ public class MapBuilder<K,V> {
         return finalizer.apply(result);
     }
 
+    public Stream<Map.Entry<K,V>> stream() {
+        return entries.stream();
+    }
+
     public Map<K,V> build(Sup<Map<K,V>> factory) {
         return build(factory, Function.identity());
     }
+
+    public static <K, V> MapBuilder<K, V> with(K key, V value) {
+        return new MapBuilder<K, V>().entry(key, value);
+    }
 }

src/main/java/net/woggioni/jwo/MavenVersion.java

@@ -0,0 +1,701 @@
+package net.woggioni.jwo;
+
+import java.math.BigInteger;
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Deque;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Locale;
+import java.util.Properties;
+
+/**
+ * <p>
+ * Generic implementation of version comparison. Shamelessly borrowed from
+ * https://github.com/apache/maven/blob/master/maven-artifact/src/main/java/org/apache/maven/artifact/versioning/ComparableVersion.java
+ * </p>
+ *
+ * Features:
+ * <ul>
+ * <li>mixing of '<code>-</code>' (hyphen) and '<code>.</code>' (dot) separators,</li>
+ * <li>transition between characters and digits also constitutes a separator:
+ *     <code>1.0alpha1 =&gt; [1, 0, alpha, 1]</code></li>
+ * <li>unlimited number of version components,</li>
+ * <li>version components in the text can be digits or strings,</li>
+ * <li>strings are checked for well-known qualifiers and the qualifier ordering is used for version ordering.
+ *     Well-known qualifiers (case insensitive) are:<ul>
+ *     <li><code>alpha</code> or <code>a</code></li>
+ *     <li><code>beta</code> or <code>b</code></li>
+ *     <li><code>milestone</code> or <code>m</code></li>
+ *     <li><code>rc</code> or <code>cr</code></li>
+ *     <li><code>snapshot</code></li>
+ *     <li><code>(the empty string)</code> or <code>ga</code> or <code>final</code></li>
+ *     <li><code>sp</code></li>
+ *     </ul>
+ *     Unknown qualifiers are considered after known qualifiers, with lexical order (always case insensitive),
+ *   </li>
+ * <li>a hyphen usually precedes a qualifier, and is always less important than digits/number, for example
+ *   {@code 1.0.RC2 < 1.0-RC3 < 1.0.1}; but prefer {@code 1.0.0-RC1} over {@code 1.0.0.RC1}, and more
+ *   generally: {@code 1.0.X2 < 1.0-X3 < 1.0.1} for any string {@code X}; but prefer {@code 1.0.0-X1}
+ *   over {@code 1.0.0.X1}.</li>
+ * </ul>
+ *
+ * @see <a href="https://cwiki.apache.org/confluence/display/MAVENOLD/Versioning">"Versioning" on Maven Wiki</a>
+ * @author <a href="mailto:kenney@apache.org">Kenney Westerhof</a>
+ * @author <a href="mailto:hboutemy@apache.org">Hervè Boutemy</a>
+ */
+public class MavenVersion implements Comparable<MavenVersion> {
+    private static final int MAX_INTITEM_LENGTH = 9;
+
+    private static final int MAX_LONGITEM_LENGTH = 18;
+
+    private String value;
+
+    private String canonical;
+
+    private ListItem items;
+
+    private interface Item {
+        int INT_ITEM = 3;
+        int LONG_ITEM = 4;
+        int BIGINTEGER_ITEM = 0;
+        int STRING_ITEM = 1;
+        int LIST_ITEM = 2;
+
+        int compareTo(Item item);
+
+        int getType();
+
+        boolean isNull();
+    }
+
+    /**
+     * Represents a numeric item in the version item list that can be represented with an int.
+     */
+    private static class IntItem implements Item {
+        private final int value;
+
+        public static final IntItem ZERO = new IntItem();
+
+        private IntItem() {
+            this.value = 0;
+        }
+
+        IntItem(String str) {
+            this.value = Integer.parseInt(str);
+        }
+
+        @Override
+        public int getType() {
+            return INT_ITEM;
+        }
+
+        @Override
+        public boolean isNull() {
+            return value == 0;
+        }
+
+        @Override
+        public int compareTo(Item item) {
+            if (item == null) {
+                return (value == 0) ? 0 : 1; // 1.0 == 1, 1.1 > 1
+            }
+
+            switch (item.getType()) {
+                case INT_ITEM:
+                    int itemValue = ((IntItem) item).value;
+                    return Integer.compare(value, itemValue);
+                case LONG_ITEM:
+                case BIGINTEGER_ITEM:
+                    return -1;
+
+                case STRING_ITEM:
+                    return 1; // 1.1 > 1-sp
+
+                case LIST_ITEM:
+                    return 1; // 1.1 > 1-1
+
+                default:
+                    throw new IllegalStateException("invalid item: " + item.getClass());
+            }
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+
+            IntItem intItem = (IntItem) o;
+
+            return value == intItem.value;
+        }
+
+        @Override
+        public int hashCode() {
+            return value;
+        }
+
+        @Override
+        public String toString() {
+            return Integer.toString(value);
+        }
+    }
+
+    /**
+     * Represents a numeric item in the version item list that can be represented with a long.
+     */
+    private static class LongItem implements Item {
+        private final long value;
+
+        LongItem(String str) {
+            this.value = Long.parseLong(str);
+        }
+
+        @Override
+        public int getType() {
+            return LONG_ITEM;
+        }
+
+        @Override
+        public boolean isNull() {
+            return value == 0;
+        }
+
+        @Override
+        public int compareTo(Item item) {
+            if (item == null) {
+                return (value == 0) ? 0 : 1; // 1.0 == 1, 1.1 > 1
+            }
+
+            switch (item.getType()) {
+                case INT_ITEM:
+                    return 1;
+                case LONG_ITEM:
+                    long itemValue = ((LongItem) item).value;
+                    return Long.compare(value, itemValue);
+                case BIGINTEGER_ITEM:
+                    return -1;
+
+                case STRING_ITEM:
+                    return 1; // 1.1 > 1-sp
+
+                case LIST_ITEM:
+                    return 1; // 1.1 > 1-1
+
+                default:
+                    throw new IllegalStateException("invalid item: " + item.getClass());
+            }
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+
+            LongItem longItem = (LongItem) o;
+
+            return value == longItem.value;
+        }
+
+        @Override
+        public int hashCode() {
+            return (int) (value ^ (value >>> 32));
+        }
+
+        @Override
+        public String toString() {
+            return Long.toString(value);
+        }
+    }
+
+    /**
+     * Represents a numeric item in the version item list.
+     */
+    private static class BigIntegerItem implements Item {
+        private final BigInteger value;
+
+        BigIntegerItem(String str) {
+            this.value = new BigInteger(str);
+        }
+
+        @Override
+        public int getType() {
+            return BIGINTEGER_ITEM;
+        }
+
+        @Override
+        public boolean isNull() {
+            return BigInteger.ZERO.equals(value);
+        }
+
+        @Override
+        public int compareTo(Item item) {
+            if (item == null) {
+                return BigInteger.ZERO.equals(value) ? 0 : 1; // 1.0 == 1, 1.1 > 1
+            }
+
+            switch (item.getType()) {
+                case INT_ITEM:
+                case LONG_ITEM:
+                    return 1;
+
+                case BIGINTEGER_ITEM:
+                    return value.compareTo(((BigIntegerItem) item).value);
+
+                case STRING_ITEM:
+                    return 1; // 1.1 > 1-sp
+
+                case LIST_ITEM:
+                    return 1; // 1.1 > 1-1
+
+                default:
+                    throw new IllegalStateException("invalid item: " + item.getClass());
+            }
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+
+            BigIntegerItem that = (BigIntegerItem) o;
+
+            return value.equals(that.value);
+        }
+
+        @Override
+        public int hashCode() {
+            return value.hashCode();
+        }
+
+        public String toString() {
+            return value.toString();
+        }
+    }
+
+    /**
+     * Represents a string in the version item list, usually a qualifier.
+     */
+    private static class StringItem implements Item {
+        private static final List<String> QUALIFIERS =
+            Arrays.asList("alpha", "beta", "milestone", "rc", "snapshot", "", "sp");
+
+        private static final Properties ALIASES = new Properties();
+
+        static {
+            ALIASES.put("ga", "");
+            ALIASES.put("final", "");
+            ALIASES.put("release", "");
+            ALIASES.put("cr", "rc");
+        }
+
+        /**
+         * A comparable value for the empty-string qualifier. This one is used to determine if a given qualifier makes
+         * the version older than one without a qualifier, or more recent.
+         */
+        private static final String RELEASE_VERSION_INDEX = String.valueOf(QUALIFIERS.indexOf(""));
+
+        private final String value;
+
+        StringItem(String value, boolean followedByDigit) {
+            if (followedByDigit && value.length() == 1) {
+                // a1 = alpha-1, b1 = beta-1, m1 = milestone-1
+                switch (value.charAt(0)) {
+                    case 'a':
+                        value = "alpha";
+                        break;
+                    case 'b':
+                        value = "beta";
+                        break;
+                    case 'm':
+                        value = "milestone";
+                        break;
+                    default:
+                }
+            }
+            this.value = ALIASES.getProperty(value, value);
+        }
+
+        @Override
+        public int getType() {
+            return STRING_ITEM;
+        }
+
+        @Override
+        public boolean isNull() {
+            return (comparableQualifier(value).compareTo(RELEASE_VERSION_INDEX) == 0);
+        }
+
+        /**
+         * Returns a comparable value for a qualifier.
+         *
+         * This method takes into account the ordering of known qualifiers then unknown qualifiers with lexical
+         * ordering.
+         *
+         * just returning an Integer with the index here is faster, but requires a lot of if/then/else to check for -1
+         * or QUALIFIERS.size and then resort to lexical ordering. Most comparisons are decided by the first character,
+         * so this is still fast. If more characters are needed then it requires a lexical sort anyway.
+         *
+         * @param qualifier
+         * @return an equivalent value that can be used with lexical comparison
+         */
+        public static String comparableQualifier(String qualifier) {
+            int i = QUALIFIERS.indexOf(qualifier);
+
+            return i == -1 ? (QUALIFIERS.size() + "-" + qualifier) : String.valueOf(i);
+        }
+
+        @Override
+        public int compareTo(Item item) {
+            if (item == null) {
+                // 1-rc < 1, 1-ga > 1
+                return comparableQualifier(value).compareTo(RELEASE_VERSION_INDEX);
+            }
+            switch (item.getType()) {
+                case INT_ITEM:
+                case LONG_ITEM:
+                case BIGINTEGER_ITEM:
+                    return -1; // 1.any < 1.1 ?
+
+                case STRING_ITEM:
+                    return comparableQualifier(value).compareTo(comparableQualifier(((StringItem) item).value));
+
+                case LIST_ITEM:
+                    return -1; // 1.any < 1-1
+
+                default:
+                    throw new IllegalStateException("invalid item: " + item.getClass());
+            }
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) {
+                return true;
+            }
+            if (o == null || getClass() != o.getClass()) {
+                return false;
+            }
+
+            StringItem that = (StringItem) o;
+
+            return value.equals(that.value);
+        }
+
+        @Override
+        public int hashCode() {
+            return value.hashCode();
+        }
+
+        public String toString() {
+            return value;
+        }
+    }
+
+    /**
+     * Represents a version list item. This class is used both for the global item list and for sub-lists (which start
+     * with '-(number)' in the version specification).
+     */
+    private static class ListItem extends ArrayList<Item> implements Item {
+        @Override
+        public int getType() {
+            return LIST_ITEM;
+        }
+
+        @Override
+        public boolean isNull() {
+            return (size() == 0);
+        }
+
+        void normalize() {
+            for (int i = size() - 1; i >= 0; i--) {
+                Item lastItem = get(i);
+
+                if (lastItem.isNull()) {
+                    // remove null trailing items: 0, "", empty list
+                    remove(i);
+                } else if (!(lastItem instanceof ListItem)) {
+                    break;
+                }
+            }
+        }
+
+        @Override
+        public int compareTo(Item item) {
+            if (item == null) {
+                if (size() == 0) {
+                    return 0; // 1-0 = 1- (normalize) = 1
+                }
+                // Compare the entire list of items with null - not just the first one, MNG-6964
+                for (Item i : this) {
+                    int result = i.compareTo(null);
+                    if (result != 0) {
+                        return result;
+                    }
+                }
+                return 0;
+            }
+            switch (item.getType()) {
+                case INT_ITEM:
+                case LONG_ITEM:
+                case BIGINTEGER_ITEM:
+                    return -1; // 1-1 < 1.0.x
+
+                case STRING_ITEM:
+                    return 1; // 1-1 > 1-sp
+
+                case LIST_ITEM:
+                    Iterator<Item> left = iterator();
+                    Iterator<Item> right = ((ListItem) item).iterator();
+
+                    while (left.hasNext() || right.hasNext()) {
+                        Item l = left.hasNext() ? left.next() : null;
+                        Item r = right.hasNext() ? right.next() : null;
+
+                        // if this is shorter, then invert the compare and mul with -1
+                        int result = l == null ? (r == null ? 0 : -1 * r.compareTo(l)) : l.compareTo(r);
+
+                        if (result != 0) {
+                            return result;
+                        }
+                    }
+
+                    return 0;
+
+                default:
+                    throw new IllegalStateException("invalid item: " + item.getClass());
+            }
+        }
+
+        @Override
+        public String toString() {
+            StringBuilder buffer = new StringBuilder();
+            for (Item item : this) {
+                if (buffer.length() > 0) {
+                    buffer.append((item instanceof ListItem) ? '-' : '.');
+                }
+                buffer.append(item);
+            }
+            return buffer.toString();
+        }
+
+        /**
+         * Return the contents in the same format that is used when you call toString() on a List.
+         */
+        private String toListString() {
+            StringBuilder buffer = new StringBuilder();
+            buffer.append("[");
+            for (Item item : this) {
+                if (buffer.length() > 1) {
+                    buffer.append(", ");
+                }
+                if (item instanceof ListItem) {
+                    buffer.append(((ListItem) item).toListString());
+                } else {
+                    buffer.append(item);
+                }
+            }
+            buffer.append("]");
+            return buffer.toString();
+        }
+    }
+
+    public MavenVersion(String version) {
+        parseVersion(version);
+    }
+
+    @SuppressWarnings("checkstyle:innerassignment")
+    public final void parseVersion(String version) {
+        this.value = version;
+
+        items = new ListItem();
+
+        version = version.toLowerCase(Locale.ENGLISH);
+
+        ListItem list = items;
+
+        Deque<Item> stack = new ArrayDeque<>();
+        stack.push(list);
+
+        boolean isDigit = false;
+
+        int startIndex = 0;
+
+        for (int i = 0; i < version.length(); i++) {
+            char c = version.charAt(i);
+
+            if (c == '.') {
+                if (i == startIndex) {
+                    list.add(IntItem.ZERO);
+                } else {
+                    list.add(parseItem(isDigit, version.substring(startIndex, i)));
+                }
+                startIndex = i + 1;
+            } else if (c == '-') {
+                if (i == startIndex) {
+                    list.add(IntItem.ZERO);
+                } else {
+                    list.add(parseItem(isDigit, version.substring(startIndex, i)));
+                }
+                startIndex = i + 1;
+
+                list.add(list = new ListItem());
+                stack.push(list);
+            } else if (Character.isDigit(c)) {
+                if (!isDigit && i > startIndex) {
+                    // 1.0.0.X1 < 1.0.0-X2
+                    // treat .X as -X for any string qualifier X
+                    if (!list.isEmpty()) {
+                        list.add(list = new ListItem());
+                        stack.push(list);
+                    }
+
+                    list.add(new StringItem(version.substring(startIndex, i), true));
+                    startIndex = i;
+
+                    list.add(list = new ListItem());
+                    stack.push(list);
+                }
+
+                isDigit = true;
+            } else {
+                if (isDigit && i > startIndex) {
+                    list.add(parseItem(true, version.substring(startIndex, i)));
+                    startIndex = i;
+
+                    list.add(list = new ListItem());
+                    stack.push(list);
+                }
+
+                isDigit = false;
+            }
+        }
+
+        if (version.length() > startIndex) {
+            // 1.0.0.X1 < 1.0.0-X2
+            // treat .X as -X for any string qualifier X
+            if (!isDigit && !list.isEmpty()) {
+                list.add(list = new ListItem());
+                stack.push(list);
+            }
+
+            list.add(parseItem(isDigit, version.substring(startIndex)));
+        }
+
+        while (!stack.isEmpty()) {
+            list = (ListItem) stack.pop();
+            list.normalize();
+        }
+    }
+
+    private static Item parseItem(boolean isDigit, String buf) {
+        if (isDigit) {
+            buf = stripLeadingZeroes(buf);
+            if (buf.length() <= MAX_INTITEM_LENGTH) {
+                // lower than 2^31
+                return new IntItem(buf);
+            } else if (buf.length() <= MAX_LONGITEM_LENGTH) {
+                // lower than 2^63
+                return new LongItem(buf);
+            }
+            return new BigIntegerItem(buf);
+        }
+        return new StringItem(buf, false);
+    }
+
+    private static String stripLeadingZeroes(String buf) {
+        if (buf == null || buf.isEmpty()) {
+            return "0";
+        }
+        for (int i = 0; i < buf.length(); ++i) {
+            char c = buf.charAt(i);
+            if (c != '0') {
+                return buf.substring(i);
+            }
+        }
+        return buf;
+    }
+
+    @Override
+    public int compareTo(MavenVersion o) {
+        return items.compareTo(o.items);
+    }
+
+    @Override
+    public String toString() {
+        return value;
+    }
+
+    public String getCanonical() {
+        if (canonical == null) {
+            canonical = items.toString();
+        }
+        return canonical;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        return (o instanceof MavenVersion) && items.equals(((MavenVersion) o).items);
+    }
+
+    @Override
+    public int hashCode() {
+        return items.hashCode();
+    }
+
+    // CHECKSTYLE_OFF: LineLength
+    /**
+     * Main to test version parsing and comparison.
+     * <p>
+     * To check how "1.2.7" compares to "1.2-SNAPSHOT", for example, you can issue
+     * <pre>java -jar ${maven.repo.local}/org/apache/maven/maven-artifact/${maven.version}/maven-artifact-${maven.version}.jar "1.2.7" "1.2-SNAPSHOT"</pre>
+     * command to command line. Result of given command will be something like this:
+     * <pre>
+     * Display parameters as parsed by Maven (in canonical form) and comparison result:
+     * 1. 1.2.7 == 1.2.7
+     *    1.2.7 &gt; 1.2-SNAPSHOT
+     * 2. 1.2-SNAPSHOT == 1.2-snapshot
+     * </pre>
+     *
+     * @param args the version strings to parse and compare. You can pass arbitrary number of version strings and always
+     * two adjacent will be compared
+     */
+    // CHECKSTYLE_ON: LineLength
+    public static void main(String... args) {
+        System.out.println("Display parameters as parsed by Maven (in canonical form and as a list of tokens) and"
+            + " comparison result:");
+        if (args.length == 0) {
+            return;
+        }
+
+        MavenVersion prev = null;
+        int i = 1;
+        for (String version : args) {
+            MavenVersion c = new MavenVersion(version);
+
+            if (prev != null) {
+                int compare = prev.compareTo(c);
+                System.out.println("   " + prev.toString() + ' ' + ((compare == 0) ? "==" : ((compare < 0) ? "<" : ">"))
+                    + ' ' + version);
+            }
+
+            System.out.println(
+                (i++) + ". " + version + " -> " + c.getCanonical() + "; tokens: " + c.items.toListString());
+
+            prev = c;
+        }
+    }
+}

src/main/java/net/woggioni/jwo/Run.java

@@ -10,5 +10,5 @@ public interface Run extends Runnable {
         exec();
     }
 
-    boolean exec() throws Throwable;
+    void exec() throws Throwable;
 }

src/main/java/net/woggioni/jwo/SQL.java

@@ -0,0 +1,96 @@
+package net.woggioni.jwo;
+
+import lombok.RequiredArgsConstructor;
+import lombok.SneakyThrows;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.Timestamp;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+import static net.woggioni.jwo.JWO.newThrowable;
+
+public class SQL {
+
+    public enum Operation {
+        INSERT
+    }
+
+    @RequiredArgsConstructor
+    public static class QueryBuilder {
+        private final Operation operation;
+        private final String tableName;
+
+        private final Map<String, Tuple2<Object, Class<?>>> fields = new TreeMap<>();
+
+        public QueryBuilder field(String name, Object value, Class<?> cls) {
+            fields.put(name, Tuple2.newInstance(value, cls));
+            return this;
+        }
+
+        public QueryBuilder field(String name, Object value) {
+            if(value == null) {
+                throw newThrowable(IllegalArgumentException.class, "Class argument required for null value");
+            }
+            return field(name, value, value.getClass());
+        }
+
+        @SneakyThrows
+        public PreparedStatement buildStatement(Connection conn) {
+            StringBuilder sb = new StringBuilder();
+            switch (operation) {
+                case INSERT:
+                    sb.append("INSERT INTO ");
+                    sb.append(tableName);
+                    sb.append(" (");
+                    int i = 0;
+                    List<Map.Entry<String, Tuple2<Object, Class<?>>>> entries = new ArrayList<>(fields.entrySet());
+                    for(Map.Entry<String, Tuple2<Object, Class<?>>> entry : entries) {
+                        if(i++ > 0) sb.append(',');
+                        sb.append(entry.getKey());
+                    }
+                    sb.append(") VALUES(");
+                    while(i-->0) {
+                        sb.append("?");
+                        if(i > 0) sb.append(',');
+                    }
+                    sb.append(");");
+                    PreparedStatement stmt = conn.prepareStatement(sb.toString());
+                    i = 1;
+                    for(Map.Entry<String, Tuple2<Object, Class<?>>> entry : entries) {
+                        Tuple2<Object, Class<?>> tuple2 = entry.getValue();
+                        Object value = tuple2.get_1();
+                        Class<?> cls = tuple2.get_2();
+                        if(cls.isAssignableFrom(String.class)) {
+                            stmt.setString(i, (String) value);
+                        } else if(cls.isAssignableFrom(Integer.class)) {
+                            stmt.setInt(i, (Integer) value);
+                        } else if(cls.isAssignableFrom(Double.class)) {
+                            stmt.setDouble(i, (Double) value);
+                        } else if(cls.isAssignableFrom(Float.class)) {
+                            stmt.setFloat(i, (Float) value);
+                        } else if(cls.isAssignableFrom(Short.class)) {
+                            stmt.setShort(i, (Short) value);
+                        } else if(cls.isAssignableFrom(Byte.class)) {
+                            stmt.setByte(i, (Byte) value);
+                        } else if(cls.isAssignableFrom(Boolean.class)) {
+                            stmt.setBoolean(i, (Boolean) value);
+                        } else if(cls.isAssignableFrom(Timestamp.class)) {
+                            stmt.setTimestamp(i, (Timestamp) value);
+                        } else {
+                            throw newThrowable(IllegalArgumentException.class, "Class '%s' is not supported",
+                                value.getClass());
+                        }
+                        ++i;
+                    }
+                    return stmt;
+                default:
+                    throw new RuntimeException("This should never happen");
+            }
+        }
+
+    }
+}

src/main/java/net/woggioni/jwo/UncloseableWriter.java

@@ -0,0 +1,14 @@
+package net.woggioni.jwo;
+
+import java.io.FilterWriter;
+import java.io.IOException;
+import java.io.Writer;
+
+public class UncloseableWriter extends FilterWriter {
+    public UncloseableWriter(Writer destination) {
+        super(destination);
+    }
+
+    @Override
+    public void close() throws IOException {}
+}

src/main/java/net/woggioni/jwo/UnmodifiableDelegatingMap.java

@@ -100,7 +100,7 @@ public class UnmodifiableDelegatingMap<K, V> implements Map<K, V> {
                 mapFactory,
                 Map.Entry::getKey,
                 Map.Entry::getValue,
-                CollectionUtils::newValueMerger
+                CollectionUtils.MapMergeStrategy.REPLACE
             )
         );
     }

src/main/java/net/woggioni/jwo/url/classpath/Handler.java

@@ -0,0 +1,24 @@
+package net.woggioni.jwo.url.classpath;
+
+import java.io.IOException;
+import java.net.URL;
+import java.net.URLConnection;
+import java.net.URLStreamHandler;
+
+public class Handler extends URLStreamHandler {
+    private final ClassLoader classLoader;
+
+    public Handler() {
+        this.classLoader = getClass().getClassLoader();
+    }
+
+    public Handler(ClassLoader classLoader) {
+        this.classLoader = classLoader;
+    }
+
+    @Override
+    protected URLConnection openConnection(URL u) throws IOException {
+        final URL resourceUrl = classLoader.getResource(u.getPath());
+        return resourceUrl.openConnection();
+    }
+}

src/main/java/net/woggioni/jwo/xml/DocumentWalker.java

@@ -0,0 +1,102 @@
+package net.woggioni.jwo.xml;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import lombok.Setter;
+import org.w3c.dom.Node;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+
+@Getter
+class StackElement {
+
+    @Setter
+    private XMLNodeVisitor.NodeVisitResultPre resultPre;
+    private final Node node;
+    private final NodeListIterator iterator;
+
+    StackElement(Node node) {
+        this.resultPre = null;
+        this.node = node;
+        this.iterator = new NodeListIterator(node.getChildNodes());
+    }
+}
+
+class Stack {
+    private final List<StackElement> stack = new ArrayList<>();
+
+    private final List<Node> nodeStack = new ArrayList<>();
+    private final List<Node> nodes = Collections.unmodifiableList(nodeStack);
+
+
+    public void push(Node node) {
+        stack.add(new StackElement(node));
+        nodeStack.add(node);
+    }
+
+    public StackElement last() {
+        return stack.get(stack.size() - 1);
+    }
+
+    public StackElement pop() {
+        nodeStack.remove(nodeStack.size() -1);
+        return stack.remove(stack.size() - 1);
+    }
+
+    public List<Node> nodes() {
+        return nodes;
+    }
+
+    public boolean isNotEmpty() {
+        return !stack.isEmpty();
+    }
+}
+
+@RequiredArgsConstructor
+public class DocumentWalker {
+
+    public static void walk(Node root, XMLNodeVisitor visitor) {
+        new DocumentWalker(root).walk(visitor);
+    }
+
+    private final Node root;
+
+    public void walk(XMLNodeVisitor visitor) {
+        Stack stack = new Stack();
+        stack.push(root);
+
+        loop:
+        while(stack.isNotEmpty()) {
+            StackElement se = stack.last();
+            if(se.getIterator().hasNext()) {
+                Node childNode = se.getIterator().next();
+                XMLNodeVisitor.NodeVisitResultPre result = se.getResultPre();
+                if(result == null) {
+                    result = visitor.visitNodePre(stack.nodes());
+                    se.setResultPre(result);
+                }
+                switch (result) {
+                    case CONTINUE:
+                        stack.push(childNode);
+                        break;
+                    case SKIP_SUBTREE:
+                        break;
+                    case END_TRAVERSAL:
+                        break loop;
+                }
+            } else {
+                XMLNodeVisitor.NodeVisitResultPost result = visitor.visitNodePost(stack.nodes());
+                stack.pop();
+                switch (result) {
+                    case CONTINUE:
+                        break;
+                    case END_TRAVERSAL:
+                        break loop;
+                }
+            }
+        }
+    }
+}

src/main/java/net/woggioni/jwo/xml/ElementBuilder.java

@@ -0,0 +1,77 @@
+package net.woggioni.jwo.xml;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import net.woggioni.jwo.MapBuilder;
+import net.woggioni.jwo.Tuple2;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.function.Consumer;
+
+@RequiredArgsConstructor
+public class ElementBuilder {
+
+    private final Document doc;
+
+    @Getter
+    private final Element root;
+
+    public ElementBuilder node(String name) {
+        return node(name, eb -> {
+        });
+    }
+
+    public ElementBuilder node(String name, Consumer<ElementBuilder> cb) {
+        Element child = doc.createElement(name);
+        if(root == null) {
+            doc.appendChild(child);
+        } else {
+            root.appendChild(child);
+        }
+        ElementBuilder eb = new ElementBuilder(doc, child);
+        cb.accept(eb);
+        return eb;
+    }
+
+    public final ElementBuilder node(String name, String textContent, Map<String, String> attrs) {
+        return node(name, eb -> {
+            if(textContent != null) eb.text(textContent);
+            for(Map.Entry<String, String> attr : attrs.entrySet()) {
+                eb.attr(attr.getKey(), attr.getValue());
+            }
+        });
+    }
+
+    @SafeVarargs
+    public final ElementBuilder node(String name, String textContent, Tuple2<String, String>...attrs) {
+        MapBuilder<String, String> mapBuilder = new MapBuilder<>();
+        for(Tuple2<String, String> attr : attrs) {
+            mapBuilder.entry(attr.get_1(), attr.get_2());
+        }
+        return node(name, textContent, mapBuilder.build(TreeMap::new));
+    }
+
+    @SafeVarargs
+    public final ElementBuilder node(String name, Tuple2<String, String>...attrs) {
+        return node(name, null, attrs);
+    }
+
+    public final ElementBuilder node(String name, Map<String, String> attrs) {
+        return node(name, null, attrs);
+    }
+
+    public ElementBuilder text(String textContent) {
+        root.setTextContent(textContent);
+        return this;
+    }
+
+    public ElementBuilder attr(String name, String value) {
+        root.setAttribute(name, value);
+        return this;
+    }
+
+
+}

src/main/java/net/woggioni/jwo/xml/ElementIterator.java

@@ -0,0 +1,49 @@
+package net.woggioni.jwo.xml;
+
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+import java.util.Objects;
+
+public class ElementIterator implements Iterator<Element> {
+    private final NodeListIterator it;
+    private final String name;
+    private Element next;
+
+    public ElementIterator(Element parent) {
+        this(parent, null);
+    }
+
+    public ElementIterator(Element parent, String name) {
+        it = new NodeListIterator(parent.getChildNodes());
+        this.name = name;
+        next = getNext();
+    }
+
+    @Override
+    public boolean hasNext() {
+        return next != null;
+    }
+
+    @Override
+    public Element next() {
+        if(next == null) throw new NoSuchElementException();
+        Element result = next;
+        next = getNext();
+        return result;
+    }
+
+    private Element getNext() {
+        Element result = null;
+        while(it.hasNext()) {
+            Node node = it.next();
+            if(node instanceof Element && (name == null || Objects.equals(name, ((Element) node).getTagName()))) {
+                result = (Element) node;
+                break;
+            }
+        }
+        return result;
+    }
+}

src/main/java/net/woggioni/jwo/xml/NodeListIterator.java

@@ -0,0 +1,27 @@
+package net.woggioni.jwo.xml;
+
+import lombok.RequiredArgsConstructor;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+@RequiredArgsConstructor
+public class NodeListIterator implements Iterator<Node> {
+
+    private final NodeList nodeList;
+
+    private int cursor = 0;
+
+    @Override
+    public boolean hasNext() {
+        return cursor < nodeList.getLength();
+    }
+
+    @Override
+    public Node next() {
+        if(hasNext()) return nodeList.item(cursor++);
+        else throw new NoSuchElementException();
+    }
+}

src/main/java/net/woggioni/jwo/xml/XMLNodeVisitor.java

@@ -0,0 +1,48 @@
+package net.woggioni.jwo.xml;
+
+import org.w3c.dom.Node;
+
+import java.util.List;
+import java.util.Objects;
+
+public interface XMLNodeVisitor {
+    default NodeVisitResultPre visitNodePre(List<Node> stack) {
+        return NodeVisitResultPre.CONTINUE;
+    }
+
+    default NodeVisitResultPost visitNodePost(List<Node> stack) {
+        return NodeVisitResultPost.CONTINUE;
+    }
+
+    enum NodeVisitResultPre {
+        CONTINUE, SKIP_SUBTREE, END_TRAVERSAL
+    }
+
+    enum NodeVisitResultPost {
+        CONTINUE, END_TRAVERSAL
+    }
+
+    static boolean stackMatches(List<Node> nodes, String... names) {
+        return stackMatches(nodes, false, names);
+    }
+
+    static boolean stackSame(List<Node> nodes, String... names) {
+        return stackMatches(nodes, true, names);
+    }
+
+    static boolean stackMatches(List<Node> nodes, boolean strict, String... names) {
+        if(nodes.size() < names.length) return false;
+        int nameIndex = 0;
+        int nodeIndex = 0;
+        while(nameIndex < names.length) {
+            if(nodeIndex >= nodes.size()) return false;
+            Node node = nodes.get(nodeIndex++);
+            if(!strict && node.getNodeType() != Node.ELEMENT_NODE) continue;
+            String name = names[nameIndex++];
+            if(name != null &&
+                node.getNodeType() == Node.ELEMENT_NODE &&
+                !Objects.equals(name, node.getNodeName())) return false;
+        }
+        return !strict || (nodeIndex == nodes.size() - 1);
+    }
+}

src/main/java/net/woggioni/jwo/xml/Xml.java

@@ -0,0 +1,91 @@
+package net.woggioni.jwo.xml;
+
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+import net.woggioni.jwo.Con;
+import net.woggioni.jwo.Fun;
+import net.woggioni.jwo.JWO;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.Spliterator;
+import java.util.Spliterators;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
+public class Xml {
+
+    public static Iterator<Node> iterator(NodeList node) {
+        return new NodeListIterator(node);
+    }
+
+    public static Iterator<Element> iterator(Element element, String tagName) {
+        return new ElementIterator(element, tagName);
+    }
+
+    public static Iterator<Element> iterator(Element element) {
+        return new ElementIterator(element);
+    }
+
+    public static Spliterator<Node> spliterator(NodeList node) {
+        return Spliterators.spliteratorUnknownSize(iterator(node), 0);
+    }
+
+    public static Spliterator<Element> spliterator(Element element) {
+        return Spliterators.spliteratorUnknownSize(iterator(element), 0);
+    }
+
+    public static Stream<Node> stream(NodeList node) {
+        return StreamSupport.stream(spliterator(node), false);
+    }
+
+    public static Stream<Element> stream(Element element) {
+        return StreamSupport.stream(spliterator(element), false);
+    }
+    public static Iterable<Node> iterable(NodeList node) {
+        return () -> iterator(node);
+    }
+
+    public static Iterable<Element> iterable(Element element, String tagName) {
+        return () -> iterator(element, tagName);
+    }
+
+    public static Iterable<Element> iterable(Element element) {
+        return () -> iterator(element);
+    }
+
+    @SuppressWarnings("unchecked")
+    public static <T> T withChild(Node node, Fun<Node, T> callback, String... path) {
+        Object[] result = new Object[1];
+        XMLNodeVisitor visitor = new XMLNodeVisitor() {
+            @Override
+            public NodeVisitResultPre visitNodePre(List<Node> stack) {
+                if (XMLNodeVisitor.stackMatches(stack, path)) {
+                    result[0] = callback.apply(JWO.tail(stack));
+                    return NodeVisitResultPre.END_TRAVERSAL;
+                } else if (stack.size() < path.length) return NodeVisitResultPre.CONTINUE;
+                else {
+                    return NodeVisitResultPre.SKIP_SUBTREE;
+                }
+            }
+        };
+        new DocumentWalker(node).walk(visitor);
+        return (T) result[0];
+    }
+
+    public static void withChild(Element element, String tagName, Con<Element> callback) {
+        for (Element el : iterable(element, tagName)) {
+            callback.accept(el);
+        }
+    }
+
+    public static void withChild(Element element, Con<Element> callback) {
+        for (Element el : iterable(element)) {
+            callback.accept(el);
+        }
+    }
+}

src/main/java9/module-info.java

@@ -1,6 +1,11 @@
 module net.woggioni.jwo {
+    requires static java.xml;
+    requires static java.sql;
     requires static lombok;
-    requires org.slf4j;
+    requires static org.slf4j;
+
     exports net.woggioni.jwo;
     exports net.woggioni.jwo.exception;
+    exports net.woggioni.jwo.url.classpath;
+    exports net.woggioni.jwo.xml;
 }