Importing upstream Jetty jetty-9.2.1.v20140609

[gigi.git] / lib / jetty / org / eclipse / jetty / util / Loader.java

diff --git a/lib/jetty/org/eclipse/jetty/util/Loader.java b/lib/jetty/org/eclipse/jetty/util/Loader.java
new file mode 100644 (file)
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+++ b/lib/jetty/org/eclipse/jetty/util/Loader.java
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+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.util;
+
+import java.io.File;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.Locale;
+import java.util.MissingResourceException;
+import java.util.ResourceBundle;
+
+import org.eclipse.jetty.util.resource.Resource;
+
+/* ------------------------------------------------------------ */
+/** ClassLoader Helper.
+ * This helper class allows classes to be loaded either from the
+ * Thread's ContextClassLoader, the classloader of the derived class
+ * or the system ClassLoader.
+ *
+ * <B>Usage:</B><PRE>
+ * public class MyClass {
+ *     void myMethod() {
+ *          ...
+ *          Class c=Loader.loadClass(this.getClass(),classname);
+ *          ...
+ *     }
+ * </PRE>          
+ * 
+ */
+public class Loader
+{
+    /* ------------------------------------------------------------ */
+    public static URL getResource(Class<?> loadClass,String name)
+    {
+        URL url =null;
+        ClassLoader context_loader=Thread.currentThread().getContextClassLoader();
+        if (context_loader!=null)
+            url=context_loader.getResource(name); 
+        
+        if (url==null && loadClass!=null)
+        {
+            ClassLoader load_loader=loadClass.getClassLoader();
+            if (load_loader!=null && load_loader!=context_loader)
+                url=load_loader.getResource(name);
+        }
+
+        if (url==null)
+            url=ClassLoader.getSystemResource(name);
+
+        return url;
+    }
+
+    /* ------------------------------------------------------------ */
+    /** Load a class.
+     * 
+     * @param loadClass
+     * @param name
+     * @return Class
+     * @throws ClassNotFoundException
+     */
+    @SuppressWarnings("rawtypes")
+    public static Class loadClass(Class loadClass,String name)
+        throws ClassNotFoundException
+    {
+        ClassNotFoundException ex=null;
+        Class<?> c =null;
+        ClassLoader context_loader=Thread.currentThread().getContextClassLoader();
+        if (context_loader!=null )
+        {
+            try { c=context_loader.loadClass(name); }
+            catch (ClassNotFoundException e) {ex=e;}
+        }    
+        
+        if (c==null && loadClass!=null)
+        {
+            ClassLoader load_loader=loadClass.getClassLoader();
+            if (load_loader!=null && load_loader!=context_loader)
+            {
+                try { c=load_loader.loadClass(name); }
+                catch (ClassNotFoundException e) {if(ex==null)ex=e;}
+            }
+        }
+
+        if (c==null)
+        {
+            try { c=Class.forName(name); }
+            catch (ClassNotFoundException e) 
+            {
+                if(ex!=null)
+                    throw ex;
+                throw e;
+            }
+        }   
+
+        return c;
+    }
+    
+    
+    
+    /* ------------------------------------------------------------ */
+    public static ResourceBundle getResourceBundle(Class<?> loadClass,String name,boolean checkParents, Locale locale)
+        throws MissingResourceException
+    {
+        MissingResourceException ex=null;
+        ResourceBundle bundle =null;
+        ClassLoader loader=Thread.currentThread().getContextClassLoader();
+        while (bundle==null && loader!=null )
+        {
+            try { bundle=ResourceBundle.getBundle(name, locale, loader); }
+            catch (MissingResourceException e) {if(ex==null)ex=e;}
+            loader=(bundle==null&&checkParents)?loader.getParent():null;
+        }      
+        
+        loader=loadClass==null?null:loadClass.getClassLoader();
+        while (bundle==null && loader!=null )
+        {
+            try { bundle=ResourceBundle.getBundle(name, locale, loader); }
+            catch (MissingResourceException e) {if(ex==null)ex=e;}
+            loader=(bundle==null&&checkParents)?loader.getParent():null;
+        }       
+
+        if (bundle==null)
+        {
+            try { bundle=ResourceBundle.getBundle(name, locale); }
+            catch (MissingResourceException e) {if(ex==null)ex=e;}
+        }   
+
+        if (bundle!=null)
+            return bundle;
+        throw ex;
+    }
+    
+    
+    /* ------------------------------------------------------------ */
+    /**
+     * Generate the classpath (as a string) of all classloaders
+     * above the given classloader.
+     * 
+     * This is primarily used for jasper.
+     * @return the system class path
+     */
+    public static String getClassPath(ClassLoader loader) throws Exception
+    {
+        StringBuilder classpath=new StringBuilder();
+        while (loader != null && (loader instanceof URLClassLoader))
+        {
+            URL[] urls = ((URLClassLoader)loader).getURLs();
+            if (urls != null)
+            {     
+                for (int i=0;i<urls.length;i++)
+                {
+                    Resource resource = Resource.newResource(urls[i]);
+                    File file=resource.getFile();
+                    if (file!=null && file.exists())
+                    {
+                        if (classpath.length()>0)
+                            classpath.append(File.pathSeparatorChar);
+                        classpath.append(file.getAbsolutePath());
+                    }
+                }
+            }
+            loader = loader.getParent();
+        }
+        return classpath.toString();
+    }
+}
+