initial commit

src/main/java/com/google/code/yanf4j/util/SystemUtils.java

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+/**
+ * Copyright [2009-2010] [dennis zhuang(killme2008@gmail.com)] Licensed under the Apache License,
+ * Version 2.0 (the "License"); you may not use this file except in compliance with the License. You
+ * may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by
+ * applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License
+ */
+/**
+ * Copyright [2009-2010] [dennis zhuang(killme2008@gmail.com)] Licensed under the Apache License,
+ * Version 2.0 (the "License"); you may not use this file except in compliance with the License. You
+ * may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by
+ * applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License
+ */
+package com.google.code.yanf4j.util;
+
+import java.io.IOException;
+import java.lang.reflect.Method;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.nio.channels.Selector;
+import java.nio.channels.spi.SelectorProvider;
+import java.util.Queue;
+import java.util.Random;
+
+/**
+ * System utils
+ * 
+ * @author dennis
+ * 
+ */
+public final class SystemUtils {
+
+  private SystemUtils() {
+
+  }
+
+  public static final String OS_NAME = System.getProperty("os.name");
+
+  private static boolean isLinuxPlatform = false;
+
+  static {
+    if (OS_NAME != null && OS_NAME.toLowerCase().indexOf("linux") >= 0) {
+      isLinuxPlatform = true;
+    }
+  }
+  public static final String JAVA_VERSION = System.getProperty("java.version");
+  private static boolean isAfterJava6u4Version = false;
+  static {
+    if (JAVA_VERSION != null) {
+      // java4 or java5
+      if (JAVA_VERSION.indexOf("1.4.") >= 0 || JAVA_VERSION.indexOf("1.5.") >= 0) {
+        isAfterJava6u4Version = false;
+      } else if (JAVA_VERSION.indexOf("1.6.") >= 0) {
+        int index = JAVA_VERSION.indexOf("_");
+        if (index > 0) {
+          String subVersionStr = JAVA_VERSION.substring(index + 1);
+          if (subVersionStr != null && subVersionStr.length() > 0) {
+            try {
+              int subVersion = Integer.parseInt(subVersionStr);
+              if (subVersion >= 4) {
+                isAfterJava6u4Version = true;
+              }
+            } catch (NumberFormatException e) {
+
+            }
+          }
+        }
+        // after java6
+      } else {
+        isAfterJava6u4Version = true;
+      }
+    }
+  }
+
+  public static final boolean isLinuxPlatform() {
+    return isLinuxPlatform;
+  }
+
+  public static final boolean isAfterJava6u4Version() {
+    return isAfterJava6u4Version;
+  }
+
+  public static void main(String[] args) {
+    System.out.println(isAfterJava6u4Version());
+  }
+
+  public static final int getSystemThreadCount() {
+    int cpus = getCpuProcessorCount();
+    if (cpus <= 8) {
+      return cpus;
+    } else {
+      return 8 + (cpus - 8) * 5 / 8;
+    }
+  }
+
+  public static final int getCpuProcessorCount() {
+    return Runtime.getRuntime().availableProcessors();
+  }
+
+  public static final Selector openSelector() throws IOException {
+    Selector result = null;
+    // check if it is linux os
+    if (SystemUtils.isLinuxPlatform()) {
+      try {
+        Class<?> providerClazz = Class.forName("sun.nio.ch.EPollSelectorProvider");
+        if (providerClazz != null) {
+          try {
+            Method method = providerClazz.getMethod("provider");
+            if (method != null) {
+              SelectorProvider selectorProvider = (SelectorProvider) method.invoke(null);
+              if (selectorProvider != null) {
+                result = selectorProvider.openSelector();
+              }
+            }
+          } catch (Exception e) {
+            // ignore
+          }
+        }
+      } catch (Exception e) {
+        // ignore
+      }
+    }
+    if (result == null) {
+      result = Selector.open();
+    }
+    return result;
+
+  }
+
+  public static final String getRawAddress(InetSocketAddress inetSocketAddress) {
+    InetAddress address = inetSocketAddress.getAddress();
+    return address != null ? address.getHostAddress() : inetSocketAddress.getHostName();
+  }
+
+  public static final Queue<?> createTransferQueue() {
+    try {
+      return (Queue<?>) Class.forName("java.util.concurrent.LinkedTransferQueue").newInstance();
+    } catch (Exception e) {
+      return new LinkedTransferQueue<Object>();
+    }
+  }
+
+  public static Random createRandom() {
+    return new Random();
+  }
+}