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.

2 files changed, 14 insertions, 5 deletions

diff --git a/src/java/jogamp/common/os/android/GluegenVersionActivity.java b/src/java/jogamp/common/os/android/GluegenVersionActivity.java
index 8ea10e2..5923e66 100644
--- a/src/java/jogamp/common/os/android/GluegenVersionActivity.java
+++ b/src/java/jogamp/common/os/android/GluegenVersionActivity.java
@@ -27,6 +27,7 @@
  */
 package jogamp.common.os.android;
 
+
 import com.jogamp.common.GlueGenVersion;
 import com.jogamp.common.os.Platform;
 import com.jogamp.common.util.VersionUtil;
@@ -43,7 +44,7 @@ public class GluegenVersionActivity extends Activity {
    public void onCreate(Bundle savedInstanceState) {
        Log.d(MD.TAG, "onCreate - S");
        super.onCreate(savedInstanceState);
-       StaticContext.setContext(this.getApplicationContext());
+       StaticContext.init(this.getApplicationContext());
        tv = new TextView(this);
        tv.setText(VersionUtil.getPlatformInfo()+Platform.NEWLINE+GlueGenVersion.getInstance()+Platform.NEWLINE+Platform.NEWLINE);               
        setContentView(tv);
@@ -109,7 +110,7 @@ public class GluegenVersionActivity extends Activity {
          tv.append("> destroyed"+Platform.NEWLINE);
      }
      Log.d(MD.TAG, "onDestroy - x");
-     StaticContext.setContext(null);
+     StaticContext.clear();
      super.onDestroy();  
      Log.d(MD.TAG, "onDestroy - X");
    }   
diff --git a/src/java/jogamp/common/os/android/StaticContext.java b/src/java/jogamp/common/os/android/StaticContext.java
index 56f8f13..cb55e65 100644
--- a/src/java/jogamp/common/os/android/StaticContext.java
+++ b/src/java/jogamp/common/os/android/StaticContext.java
@@ -32,13 +32,21 @@ import android.util.Log;
 
 public class StaticContext {
    private static Context context = null;
+   
    private static boolean DEBUG = false;
    
-   public static final synchronized void setContext(Context ctx) {
-       if(DEBUG) Log.d(MD.TAG, "setContext("+ctx+")");
+   public static final synchronized void init(Context ctx) {
+       if(null != context) {
+           throw new RuntimeException("Context already set");
+       }
+       if(DEBUG) { Log.d(MD.TAG, "init("+ctx+")"); }
        context = ctx;
    }
+   public static final synchronized void clear() {
+       if(DEBUG) { Log.d(MD.TAG, "clear()"); }
+       context = null;       
+   }
    public static final synchronized Context getContext() {
        return context;
-   }
+   }   
 }