improved Application class

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

@@ -1,7 +1,8 @@
 package net.woggioni.jwo;
 
 import lombok.AccessLevel;
-import lombok.NoArgsConstructor;
+import lombok.Builder;
+import lombok.RequiredArgsConstructor;
 import lombok.SneakyThrows;
 import lombok.extern.slf4j.Slf4j;
 
@@ -12,9 +13,27 @@ import java.nio.file.Paths;
 import java.util.Optional;
 import java.util.stream.Stream;
 
+import static net.woggioni.jwo.JWO.optional2Stream;
+import static net.woggioni.jwo.JWO.streamCat;
+
 @Slf4j
-@NoArgsConstructor(access = AccessLevel.PRIVATE)
+@Builder(builderMethodName = "", builderClassName = "Builder")
-class Application {
+@RequiredArgsConstructor(access = AccessLevel.PRIVATE)
+public class Application {
+    private final String name;
+    private final String configurationDirectoryPropertyKey;
+    private final String cacheDirectoryPropertyKey;
+    private final String dataDirectoryPropertyKey;
+    private final String configurationDirectoryEnvVar;
+    private final String cacheDirectoryEnvVar;
+    private final String dataDirectoryEnvVar;
+
+    private static final String MAC_FOLDER_LIBRARY = "Library";
+    private static final String MAC_FOLDER_APPLICATION_SUPPORT = "Application Support";
+
+    public static Builder builder(String name) {
+        return new Builder().name(name);
+    }
 
     private static boolean validateConfigurationDirectory(Path candidate) {
         try {
@@ -49,69 +68,142 @@ class Application {
                 .orElseThrow((Sup<Throwable>) () -> new FileNotFoundException(errorMessage));
     }
 
-    @SneakyThrows
+    private static boolean validateWritableDirectory(Path candidate) {
-    private static Path computeCacheDirectory(String appName, String jvmPropertyKey) {
+        try {
-        Stream<Path> candidates;
+            if (!Files.exists(candidate)) {
-        if(OS.isUnix) {
+                Files.createDirectories(candidate);
-            candidates = JWO.optional2Stream(
+                log.trace("Created and selected directory '{}'", candidate);
-                Optional.ofNullable(System.getProperty(jvmPropertyKey)).map(Paths::get),
+                return true;
-                Optional.ofNullable(System.getenv("XDG_CACHE_HOME")).map(prefix -> Paths.get(prefix, appName)),
+            } else if (!Files.isDirectory(candidate)) {
-                Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, ".cache", appName)),
+                log.trace("Directory '{}' discarded because it is not a directory", candidate);
-                Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, "." + appName, "cache"))
+                return false;
+            } else if (!Files.isWritable(candidate)) {
+                log.trace("Directory '{}' discarded because it is not writable", candidate);
+                return false;
+            } else {
+                log.trace("Selected existing directory '{}'", candidate);
+                return true;
+            }
+        } catch (Exception ioe) {
+            log.trace(
+                    String.format("Directory '%s' discarded: %s", candidate.toString(), ioe.getMessage()),
+                    ioe
             );
-        } else if(OS.isMac) {
+            return false;
-            candidates = JWO.optional2Stream(
+        }
+    }
+
+    @SneakyThrows
+    private Path selectWritableDirectory(Stream<Path> candidates, String successMessage, String errorMessage) {
+        return candidates
+                .filter(Application::validateWritableDirectory)
+                .peek(p -> log.debug(successMessage, p))
+                .findFirst()
+                .orElseThrow((Sup<Throwable>) () -> new FileNotFoundException(errorMessage));
+    }
+
+    @SneakyThrows
+    public Path computeCacheDirectory() {
+        Stream<Path> commonCandidates = optional2Stream(
+                Optional.ofNullable(cacheDirectoryPropertyKey).map(System::getProperty).map(Paths::get),
+                Optional.ofNullable(cacheDirectoryEnvVar).map(System::getProperty).map(Paths::get)
+        );
+        Stream<Path> osSpecificCandidates;
+        if (OS.isMac) {
+            osSpecificCandidates = optional2Stream(
                     Optional.ofNullable(System.getProperty("user.home"))
-                    .map(prefix -> Paths.get(prefix, "Library", "Application support", appName, "cache")),
+                            .map(prefix -> Paths.get(prefix, MAC_FOLDER_LIBRARY, MAC_FOLDER_APPLICATION_SUPPORT, name, "cache")),
-                Optional.ofNullable(System.getProperty("user.home"))
+                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, "." + name, "cache"))
-                    .map(prefix -> Paths.get(prefix, "." + appName, "cache"))
+            );
+        } else if (OS.isUnix) {
+            osSpecificCandidates = optional2Stream(
+                    Optional.ofNullable(System.getenv("XDG_CACHE_HOME")).map(prefix -> Paths.get(prefix, name)),
+                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, ".cache", name)),
+                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, "." + name, "cache"))
             );
         } else if (OS.isWindows) {
-            candidates = JWO.optional2Stream(
+            osSpecificCandidates = optional2Stream(
                     Optional.ofNullable(System.getenv("LOCALAPPDATA"))
-                    .map(prefix -> Paths.get(prefix, appName, "cache")),
+                            .map(prefix -> Paths.get(prefix, name, "cache")),
                     Optional.ofNullable(System.getProperty("user.home"))
-                    .map(prefix -> Paths.get(prefix, "Application Data", "Local Settings", "Application Data", appName, "cache")));
+                            .map(prefix -> Paths.get(prefix, "Application Data", "Local Settings", "Application Data", name, "cache")));
         } else {
-            candidates = JWO.optional2Stream(
+            osSpecificCandidates = optional2Stream(
                     Optional.ofNullable(System.getProperty("user.home"))
-                    .map(prefix -> Paths.get(prefix, "." + appName, "cache")));
+                            .map(prefix -> Paths.get(prefix, "." + name, "cache")));
         }
-        return selectCandidate(candidates,
+        return selectWritableDirectory(streamCat(commonCandidates, osSpecificCandidates),
                 "Using cache directory '{}'",
                 "Unable to find a usable cache directory");
     }
 
-
     @SneakyThrows
-    private static Path computeConfigurationDirectory(String appName, String jvmPropertyKey) {
+    public Path computeDataDirectory() {
-        Stream<Path> candidates;
+        Stream<Path> commonCandidates = optional2Stream(
-        if(OS.isUnix) {
+                Optional.ofNullable(dataDirectoryPropertyKey).map(System::getProperty).map(Paths::get),
-            candidates = JWO.optional2Stream(
+                Optional.ofNullable(dataDirectoryEnvVar).map(System::getProperty).map(Paths::get)
-                    Optional.ofNullable(System.getProperty(jvmPropertyKey)).map(Paths::get),
-                    Optional.ofNullable(System.getenv("XDG_CONFIG_HOME")).map(prefix -> Paths.get(prefix, appName)),
-                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, ".config", appName)),
-                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, "." + appName, "config"))
         );
-        } else if(OS.isMac) {
+        Stream<Path> osSpecificCandidates;
-            candidates = JWO.optional2Stream(
+        if (OS.isMac) {
+            osSpecificCandidates = optional2Stream(
                     Optional.ofNullable(System.getProperty("user.home"))
-                        .map(prefix -> Paths.get(prefix, "Library", "Application support", appName, "config")),
+                            .map(prefix -> Paths.get(prefix, MAC_FOLDER_LIBRARY, MAC_FOLDER_APPLICATION_SUPPORT, name)),
-                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, "." + appName, "config"))
+                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, "." + name))
+            );
+        } else if (OS.isUnix) {
+            osSpecificCandidates = optional2Stream(
+                    Optional.ofNullable(System.getenv("XDG_DATA_HOME")).map(prefix -> Paths.get(prefix, name)),
+                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, ".local", "share", name)),
+                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, "." + name))
             );
         } else if (OS.isWindows) {
-            candidates = JWO.optional2Stream(
+            osSpecificCandidates = optional2Stream(
                     Optional.ofNullable(System.getenv("LOCALAPPDATA"))
-                        .map(prefix -> Paths.get(prefix, appName, "config")),
+                            .map(prefix -> Paths.get(prefix, name)),
                     Optional.ofNullable(System.getProperty("user.home"))
-                        .map(prefix -> Paths.get(prefix, "Application Data", "Local Settings", "Application Data", appName, "config")));
+                            .map(prefix -> Paths.get(prefix, "Application Data", "Local Settings", "Application Data", name)));
         } else {
-            candidates = JWO.optional2Stream(Optional.ofNullable(System.getProperty("user.home"))
+            osSpecificCandidates = optional2Stream(
-                .map(prefix -> Paths.get(prefix, "." + appName, "config")));
+                    Optional.ofNullable(System.getProperty("user.home"))
+                            .map(prefix -> Paths.get(prefix, "." + name)));
         }
-        return selectCandidate(candidates,
+        return selectWritableDirectory(streamCat(commonCandidates, osSpecificCandidates),
+                "Using data directory '{}'",
+                "Unable to find a usable data directory");
+    }
+
+    @SneakyThrows
+    public Path computeConfigurationDirectory() {
+        Stream<Path> commonCandidates = optional2Stream(
+                Optional.ofNullable(configurationDirectoryPropertyKey).map(System::getProperty).map(Paths::get),
+                Optional.ofNullable(configurationDirectoryEnvVar).map(System::getProperty).map(Paths::get)
+        );
+        Stream<Path> osSpecificCandidates;
+        if (OS.isMac) {
+            osSpecificCandidates = optional2Stream(
+                    Optional.ofNullable(System.getProperty("user.home"))
+                            .map(prefix -> Paths.get(prefix, MAC_FOLDER_LIBRARY, MAC_FOLDER_APPLICATION_SUPPORT, name, "config")),
+                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, "." + name, "config"))
+            );
+        } else if (OS.isUnix) {
+            osSpecificCandidates = optional2Stream(
+                    Optional.ofNullable(System.getenv("XDG_CONFIG_HOME")).map(prefix -> Paths.get(prefix, name)),
+                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, ".config", name)),
+                    Optional.ofNullable(System.getProperty("user.home")).map(prefix -> Paths.get(prefix, "." + name, "config"))
+            );
+        } else if (OS.isWindows) {
+            osSpecificCandidates = optional2Stream(
+                    Optional.ofNullable(System.getenv("LOCALAPPDATA"))
+                            .map(prefix -> Paths.get(prefix, name, "config")),
+                    Optional.ofNullable(System.getProperty("user.home"))
+                            .map(prefix -> Paths.get(prefix, "Application Data", "Local Settings", "Application Data", name, "config")));
+        } else {
+            osSpecificCandidates = optional2Stream(
+                    Optional.ofNullable(System.getProperty("user.home")
+                    ).map(prefix -> Paths.get(prefix, "." + name, "config")));
+        }
+        return selectWritableDirectory(streamCat(commonCandidates, osSpecificCandidates),
                 "Using configuration directory '{}'",
                 "Unable to find a usable configuration directory");
     }
-
 }

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

@@ -426,40 +426,6 @@ public class JWO {
         return sb.toString();
     }
 
-    @SneakyThrows
-    public static Path computeCacheDirectory(String appName) {
-        return Stream.of(
-                Optional.ofNullable(System.getProperty("user.home"))
-                        .map(prefix -> Paths.get(prefix, ".cache", appName)),
-                Optional.ofNullable(System.getProperty("java.io.tmpdir")).map(Paths::get).map(p -> p.resolve(appName)),
-                Optional.of(Paths.get("/tmp", appName)))
-                .flatMap(JWO::optional2Stream)
-                .filter(JWO::validateCacheDirectory)
-                .findFirst()
-                .orElseThrow(() -> newThrowable(FileNotFoundException.class, "Unable to find a usable cache directory"));
-    }
-
-    private static boolean validateCacheDirectory(Path candidate) {
-        try {
-            if (!Files.exists(candidate)) {
-                Files.createDirectories(candidate);
-                return true;
-            } else if (!Files.isDirectory(candidate)) {
-                log.debug("Cache directory '{}' discarded because it is not a directory", candidate.toString());
-                return false;
-            } else if (!Files.isWritable(candidate)) {
-                log.debug("Cache directory '{}' discarded because it is not writable", candidate.toString());
-                return false;
-            } else {
-                log.info("Using cache directory '{}'", candidate.toString());
-                return true;
-            }
-        } catch (Exception ioe) {
-            log.debug(String.format("Cache directory '%s' discarded: %s", candidate.toString(), ioe.getMessage()), ioe);
-            return false;
-        }
-    }
-
     public static <T, U extends T> Optional<U> cast(T value, Class<U> cls) {
         if (cls.isInstance(value)) {
             return Optional.of((U) value);