Add 'asset' URLConnection; IOUtil uses URLConnection / incr. effeciency; Android ClassLoaderUtil cleanup;

- Add 'asset' URLConnection
  - Please read API doc 'PiggybackURLConnection' and 'AssetURLConnection'

  - Solves generic resource handling where platform locations may differ,
    ie ClassLoader lookup on Android in the 'assets/' subfolder.

  - New Android 'AssetDexClassLoader' uses 'assets/' folder for findResource(..)

  - aapt.signed (our APK ant task)
    - uses 'assets/' folder

    - adds the 'assetsdir' attribute allowing to copy other assets into the APK

- IOUtil uses URLConnection / incr. effeciency
  - using URLConnection on all getResource(..) since URL
    is connected anyways for validation and URLConnection can be used by caller right away

  - String getRelativeOf(URL, String) -> URL getRelativeOf(URL, String)
    - preserves scheme, authority, etc
    - simple parentOf handling, more efficient

  - reusing new 'asset' protocol impl.

- Android ClassLoaderUtil cleanup;
  - Use createClassLoader(..) impl for build-in static jogamp and user APKs,
    which removes code redundancy

Tests: New code path, especially 'assets' are covered by new unit tests, no regressions on Linux.

1 files changed, 66 insertions, 0 deletions

diff --git a/src/java/com/jogamp/common/net/GenericURLStreamHandlerFactory.java b/src/java/com/jogamp/common/net/GenericURLStreamHandlerFactory.java
new file mode 100644
index 0000000..79d7f71
--- /dev/null
+++ b/src/java/com/jogamp/common/net/GenericURLStreamHandlerFactory.java
@@ -0,0 +1,66 @@
+package com.jogamp.common.net;
+
+import java.net.URL;
+import java.net.URLStreamHandler;
+import java.net.URLStreamHandlerFactory;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.util.HashMap;
+import java.util.Map;
+
+public class GenericURLStreamHandlerFactory implements URLStreamHandlerFactory {
+    private static GenericURLStreamHandlerFactory factory = null;
+    
+    private final Map<String, URLStreamHandler> protocolHandlers;
+
+    private GenericURLStreamHandlerFactory() {
+        protocolHandlers = new HashMap<String, URLStreamHandler>();
+    }
+    
+    /**
+     * Sets the <code>handler</code> for <code>protocol</code>.
+     * 
+     * @return the previous set <code>handler</code>, or null if none was set.
+     */
+    public synchronized final URLStreamHandler setHandler(String protocol, URLStreamHandler handler) {
+        return protocolHandlers.put(protocol, handler);
+    }
+    
+    /**
+     * Returns the <code>protocol</code> handler previously set via {@link #setHandler(String, URLStreamHandler)}, 
+     * or null if none was set.
+     */
+    public synchronized final URLStreamHandler getHandler(String protocol) {
+        return protocolHandlers.get(protocol);
+    }
+    
+    @Override
+    public synchronized final URLStreamHandler createURLStreamHandler(String protocol) {
+        return getHandler(protocol);
+    }
+
+    /**
+     * Returns the singleton instance of the registered GenericURLStreamHandlerFactory
+     * or null if registration was not successful.
+     * <p>
+     * Registration is only performed once.
+     * </p>
+     */
+    public synchronized static GenericURLStreamHandlerFactory register() {
+        if(null == factory) {
+            factory = AccessController.doPrivileged(new PrivilegedAction<GenericURLStreamHandlerFactory>() {
+                public GenericURLStreamHandlerFactory run() {
+                    boolean ok = false;
+                    GenericURLStreamHandlerFactory f = new GenericURLStreamHandlerFactory();
+                    try {
+                        URL.setURLStreamHandlerFactory(f);
+                        ok = true;
+                    } catch (Throwable e) {
+                        System.err.println("GenericURLStreamHandlerFactory: Setting URLStreamHandlerFactory failed: "+e.getMessage());
+                    }
+                    return ok ? f : null;
+                } } );
+        }
+        return factory;
+    }
+}