Fix Bug 583: Remove Android compile-time dependencies and exclude Android specific classes for non Android platforms.

Android specifics are delegated via class AndroidUtils,
which uses reflection to call AndroidUtilsImpl if platform is Android.

Android code is confined to the packages:
  jogamp.common.os.android.*
  jogamp.android.launcher.*

and only included when compiled for the Android platform.

7 files changed, 231 insertions, 63 deletions

diff --git a/make/build.xml b/make/build.xml
index 61e7c86..ded1154 100644
--- a/make/build.xml
+++ b/make/build.xml
@@ -26,14 +26,31 @@
     <property name="gluegen.excludes.nsig" value="com/jogamp/gluegen/runtime/BufferFactoryInternal.java com/jogamp/gluegen/nativesig/**" />
   </target>
 
-  <target name="set.debug">
-    <property name="c.compiler.debug" value="true" /> 
-    <property name="javacdebug"       value="true" /> 
-    <property name="javacdebuglevel"  value="source,lines,vars" /> 
+  <target name="init.base" depends="jogamp.env.init,gluegen.properties.load.user,gluegen.cpptasks.detect.os,setup.excludes.nsig"/>
+
+  <target name="init.std" unless="isAndroid" >
+    <!-- Create the classpath for compiling GlueGen. 
+         This requires the user-defined "antlr.jar" property. -->
+    <path id="gluegencompile.classpath">
+      <pathelement location="${antlr.jar}" />
+    </path>
+  </target>
+
+  <target name="init.android" if="isAndroid" >
+    <!-- Create the classpath for compiling Android only stuff. -->
+    <path id="android.classpath">
+      <pathelement location="${android-min.jar}"/>
+    </path>
+
+    <!-- Create the classpath for compiling GlueGen. 
+         This requires the user-defined "antlr.jar" property. -->
+    <path id="gluegencompile.classpath">
+      <pathelement location="${antlr.jar}" />
+      <pathelement location="${android-min.jar}"/>
+    </path>
   </target>
-  <target name="init.debug" depends="set.debug, init"/>
 
-  <target name="init" depends="jogamp.env.init,gluegen.properties.load.user,gluegen.cpptasks.detect.os,setup.excludes.nsig">
+  <target name="init" depends="init.base,init.std,init.android">
     <!-- Declare all paths and user defined variables. -->
 
     <!-- property name="javadoc.link" value="http://java.sun.com/j2se/1.4.2/docs/api/" /-->
@@ -103,18 +120,6 @@
       <pathelement location="${antlr.jar}" />
     </path>
     
-    <!-- Create the classpath for compiling Android only stuff. -->
-    <path id="android.classpath">
-      <pathelement location="${android-min.jar}"/>
-    </path>
-    
-    <!-- Create the classpath for compiling GlueGen. 
-         This requires the user-defined "antlr.jar" property. -->
-    <path id="gluegencompile.classpath">
-      <pathelement location="${antlr.jar}" />
-      <pathelement location="${android-min.jar}"/>
-    </path>
-    
     <!-- Create the classpath for using GlueGen. -->
     <path id="gluegen.classpath" >
       <pathelement location="${classes}" />
@@ -137,12 +142,30 @@
     <property name="archive.name"     value="gluegen-${gluegen.version}-${os.and.arch}" />
     <property name="archive"          value="${build}/${archive.name}" />
 
+    <!-- the launcher is compiled and packaged explicit - if android -->
     <property name="jogamp.android-launcher.classes" value="jogamp/android/launcher/**"/>
+
+    <!-- optional android classes - if android -->
+    <property name="java.part.android" value="jogamp/common/os/android/**"/>
+
     <property name="jogamp.awt.classes" value="jogamp/common/awt/**"/>
-    <property name="gluegen.excludes.all" value="${gluegen.excludes.nsig} ${jogamp.android-launcher.classes}" />
     <property name="gluegen-rt.classes" value="com/jogamp/gluegen/runtime/**"/>
     <property name="jogamp.common.classes" value="com/jogamp/common/** jogamp/common/**"/>
+
+    <condition property="java.excludes.android" value="${java.part.android}">
+       <not> <isset property="isAndroid"/> </not>
+    </condition>
+
+    <property name="gluegen.excludes.all" value="${gluegen.excludes.nsig} ${jogamp.android-launcher.classes} ${java.excludes.android}" />
+
+  </target>
+
+  <target name="set.debug">
+    <property name="c.compiler.debug" value="true" /> 
+    <property name="javacdebug"       value="true" /> 
+    <property name="javacdebuglevel"  value="source,lines,vars" /> 
   </target>
+  <target name="init.debug" depends="set.debug, init"/>
 
   <!--
     - Using ANTLR generate the specified Java files.
@@ -694,8 +717,8 @@
     <jar destfile="${build}/gluegen.jar" manifest="${build}/Manifest.temp">
       <fileset dir="${classes}">
         <include name="**/*.class" />
-        <exclude name="jogamp/common/os/android/**" />
         <exclude name="${jogamp.android-launcher.classes}" />
+        <exclude name="${java.part.android}" />
       </fileset>
       <fileset dir="resources/assets">
         <include name="**" />
@@ -720,6 +743,7 @@
         <include name="com/jogamp/common/**" />
         <include name="jogamp/common/**" />
         <exclude name="${jogamp.android-launcher.classes}" />
+        <exclude name="${java.excludes.android}" />
       </fileset>
       <fileset dir="resources/assets">
         <include name="**" />
diff --git a/src/java/com/jogamp/common/os/AndroidVersion.java b/src/java/com/jogamp/common/os/AndroidVersion.java
index 8886273..cb6c3e5 100644
--- a/src/java/com/jogamp/common/os/AndroidVersion.java
+++ b/src/java/com/jogamp/common/os/AndroidVersion.java
@@ -1,3 +1,30 @@
+/**
+ * Copyright 2011 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
 package com.jogamp.common.os;
 
 import java.lang.reflect.Field;
@@ -9,9 +36,6 @@ import com.jogamp.common.util.ReflectionUtil;
 public class AndroidVersion {
     public static final boolean isAvailable;
     
-    /** All SDK version map, where SDK_INT is the key to the current running version */
-    public static final Map<Integer, String> VERSION_CODES; 
-    
     /** Development codename, or the string "REL" for official release */    
     public static final String CODENAME;
     
@@ -27,8 +51,8 @@ public class AndroidVersion {
     /** SDK Version string */
     public static final String SDK_NAME;
     
-    static final String androidBuildVersion = "android.os.Build$VERSION";
-    static final String androidBuildVersionCodes = "android.os.Build$VERSION_CODES";
+    private static final String androidBuildVersion = "android.os.Build$VERSION";
+    private static final String androidBuildVersionCodes = "android.os.Build$VERSION_CODES";
     
     static {
         final ClassLoader cl = AndroidVersion.class.getClassLoader();
@@ -41,22 +65,21 @@ public class AndroidVersion {
             abvObject = abvClass.newInstance();
             abvcClass = ReflectionUtil.getClass(androidBuildVersionCodes, true, cl);
             abvcObject = abvcClass.newInstance();
-        } catch (Exception e) { /* n/a */ } 
-        isAvailable = null != abvObject ;
+        } catch (Exception e) { /* n/a */ }
+        isAvailable = null != abvObject; 
         if(isAvailable) {
             CODENAME = getString(abvClass, abvObject, "CODENAME");
             INCREMENTAL = getString(abvClass, abvObject, "INCREMENTAL");
             RELEASE = getString(abvClass, abvObject, "RELEASE");
             SDK_INT = getInt(abvClass, abvObject, "SDK_INT");
-            VERSION_CODES = getVersionCodes(abvcClass, abvcObject);
-            String sdk_name = VERSION_CODES.get(new Integer(SDK_INT));
-            SDK_NAME = ( null != sdk_name ) ? sdk_name : "SDK_"+SDK_INT ;
+            final Map<Integer, String> version_codes = getVersionCodes(abvcClass, abvcObject);
+            String sdk_name = version_codes.get(new Integer(SDK_INT));
+            SDK_NAME = ( null != sdk_name ) ? sdk_name : "SDK_"+SDK_INT ;            
         } else {
             CODENAME = null;
             INCREMENTAL = null;
             RELEASE = null;
             SDK_INT = -1;  
-            VERSION_CODES = new HashMap<Integer, String>();
             SDK_NAME = null;
         }
     }
diff --git a/src/java/com/jogamp/common/util/IOUtil.java b/src/java/com/jogamp/common/util/IOUtil.java
index 5f26c53..ed74fa2 100644
--- a/src/java/com/jogamp/common/util/IOUtil.java
+++ b/src/java/com/jogamp/common/util/IOUtil.java
@@ -44,13 +44,10 @@ import java.net.URLConnection;
 import java.nio.ByteBuffer;
 
 import jogamp.common.Debug;
-import jogamp.common.os.android.StaticContext;
-
-import android.content.Context;
+import jogamp.common.os.AndroidUtils;
 
 import com.jogamp.common.net.AssetURLContext;
 import com.jogamp.common.nio.Buffers;
-import com.jogamp.common.os.AndroidVersion;
 import com.jogamp.common.os.MachineDescription;
 import com.jogamp.common.os.Platform;
 
@@ -632,7 +629,7 @@ public class IOUtil {
      * On Android a <code>temp</code> folder relative to the applications local folder 
      * (see {@link Context#getDir(String, int)}) is returned, if
      * the Android application/activity has registered it's Application Context
-     * via {@link StaticContext#init(Context, ClassLoader)}.
+     * via {@link jogamp.common.os.android.StaticContext.StaticContext#init(Context, ClassLoader) StaticContext.init(..)}.
      * This allows using the temp folder w/o the need for <code>sdcard</code>
      * access, which would be the <code>java.io.tempdir</code> location on Android!
      * </p>
@@ -642,22 +639,14 @@ public class IOUtil {
      * @throws RuntimeException is the property <code>java.io.tmpdir</code> or the resulting temp directory is invalid
      *  
      * @see PropertyAccess#getProperty(String, boolean, java.security.AccessControlContext)
-     * @see StaticContext#init(Context, ClassLoader)
      * @see Context#getDir(String, int)
      */
     public static File getTempRoot(AccessControlContext acc)
         throws SecurityException, RuntimeException
     {
-        if(AndroidVersion.isAvailable) {
-            final Context ctx = StaticContext.getContext();
-            if(null != ctx) {
-                final File tmpRoot = ctx.getDir("temp", Context.MODE_WORLD_READABLE);
-                if(null==tmpRoot|| !tmpRoot.isDirectory() || !tmpRoot.canWrite()) {
-                    throw new RuntimeException("Not a writable directory: '"+tmpRoot+"', retrieved Android static context");
-                }
-                if(DEBUG) {
-                    System.err.println("IOUtil.getTempRoot(Android): temp dir: "+tmpRoot.getAbsolutePath());
-                }
+        {
+            final File tmpRoot = AndroidUtils.getTempRoot(acc); // null if ( !Android || no android-ctx )
+            if(null != tmpRoot) {
                 return tmpRoot;
             }
         }
@@ -670,7 +659,7 @@ public class IOUtil {
             throw new RuntimeException("Not a writable directory: '"+tmpRoot+"', retrieved by propery '"+java_io_tmpdir_propkey+"'");
         }
         if(DEBUG) {
-            System.err.println("IOUtil.getTempRoot(isAndroid: "+AndroidVersion.isAvailable+"): temp dir: "+tmpRoot.getAbsolutePath());
+            System.err.println("IOUtil.getTempRoot(): temp dir: "+tmpRoot.getAbsolutePath());
         }
         return tmpRoot;
     }
diff --git a/src/java/com/jogamp/common/util/JogampVersion.java b/src/java/com/jogamp/common/util/JogampVersion.java
index 2461c3e..de65f90 100644
--- a/src/java/com/jogamp/common/util/JogampVersion.java
+++ b/src/java/com/jogamp/common/util/JogampVersion.java
@@ -29,7 +29,6 @@
 package com.jogamp.common.util;
 
 import com.jogamp.common.GlueGenVersion;
-import com.jogamp.common.os.AndroidVersion;
 import com.jogamp.common.os.Platform;
 
 import java.util.Iterator;
@@ -37,7 +36,7 @@ import java.util.Set;
 import java.util.jar.Attributes;
 import java.util.jar.Manifest;
 
-import jogamp.common.os.android.PackageInfoUtil;
+import jogamp.common.os.AndroidUtils;
 
 public class JogampVersion {
 
@@ -48,7 +47,7 @@ public class JogampVersion {
     private Manifest mf;
     private int hash;
     private Attributes mainAttributes;
-    private Set/*<Attributes.Name>*/ mainAttributeNames;
+    private Set<?>/*<Attributes.Name>*/ mainAttributeNames;
     
     private final String androidPackageVersionName;
     
@@ -58,11 +57,7 @@ public class JogampVersion {
         this.hash = this.mf.hashCode();
         mainAttributes = this.mf.getMainAttributes();
         mainAttributeNames = mainAttributes.keySet();
-        if(AndroidVersion.isAvailable) {
-            androidPackageVersionName = PackageInfoUtil.getPackageInfoVersionName(packageName);
-        } else {
-            androidPackageVersionName = null;
-        }
+        androidPackageVersionName = AndroidUtils.getPackageInfoVersionName(packageName); // null if !Android
     }
 
     @Override
@@ -95,7 +90,7 @@ public class JogampVersion {
     }
 
     public final Attributes.Name getAttributeName(String attributeName) {
-        for (Iterator iter = mainAttributeNames.iterator(); iter.hasNext();) {
+        for (Iterator<?> iter = mainAttributeNames.iterator(); iter.hasNext();) {
             Attributes.Name an = (Attributes.Name) iter.next();
             if (an.toString().equals(attributeName)) {
                 return an;
@@ -104,7 +99,10 @@ public class JogampVersion {
         return null;
     }
 
-    public final Set getAttributeNames() {
+    /**
+     * @return set of type {@link Attributes.Name}, disguised as anonymous   
+     */
+    public final Set<?>/*<Attributes.Name>*/ getAttributeNames() {
         return mainAttributeNames;
     }
 
diff --git a/src/java/jogamp/common/os/AndroidUtils.java b/src/java/jogamp/common/os/AndroidUtils.java
new file mode 100644
index 0000000..743a736
--- /dev/null
+++ b/src/java/jogamp/common/os/AndroidUtils.java
@@ -0,0 +1,94 @@
+/**
+ * Copyright 2012 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+package jogamp.common.os;
+
+import java.io.File;
+import java.lang.reflect.Method;
+import java.security.AccessControlContext;
+
+import com.jogamp.common.os.AndroidVersion;
+import com.jogamp.common.util.ReflectionUtil;
+
+public class AndroidUtils {
+
+    private static final Method androidGetPackageInfoVersionNameMethod;
+    private static final Method androidGetPackageInfoVersionCodeMethod;
+    private static final Method androidGetTempRootMethod;
+    
+    static {
+        if(AndroidVersion.isAvailable) {
+            final ClassLoader cl = AndroidUtils.class.getClassLoader();
+            final Class<?> androidAndroidUtilsImplClz = ReflectionUtil.getClass("jogamp.common.os.android.AndroidUtilsImpl", true, cl);
+            androidGetPackageInfoVersionCodeMethod = ReflectionUtil.getMethod(androidAndroidUtilsImplClz, "getPackageInfoVersionCode", String.class);
+            androidGetPackageInfoVersionNameMethod = ReflectionUtil.getMethod(androidAndroidUtilsImplClz, "getPackageInfoVersionName", String.class);
+            androidGetTempRootMethod = ReflectionUtil.getMethod(androidAndroidUtilsImplClz, "getTempRoot", AccessControlContext.class);
+        } else {
+            androidGetPackageInfoVersionCodeMethod = null;
+            androidGetPackageInfoVersionNameMethod = null;
+            androidGetTempRootMethod = null;
+        }
+    }
+    
+    /**
+     * @return null if platform is not Android or no Android Context is registered 
+     *         via {@link jogamp.common.os.android.StaticContext#init(android.content.Context) StaticContext.init(..)}, 
+     *         otherwise the found package version code of <code>packageName</code> is returned.
+     */
+    public static final int getPackageInfoVersionCode(String packageName) {
+        if(null != androidGetPackageInfoVersionCodeMethod) {
+            return ((Integer) ReflectionUtil.callMethod(null, androidGetPackageInfoVersionCodeMethod, packageName)).intValue();
+        }
+        return -1;
+    }
+    
+    /**
+     * @return null if platform is not Android or no Android Context is registered 
+     *         via {@link jogamp.common.os.android.StaticContext#init(android.content.Context) StaticContext.init(..)}, 
+     *         otherwise the found package version name of <code>packageName</code> is returned.
+     */
+    public static final String getPackageInfoVersionName(String packageName) {
+        if(null != androidGetPackageInfoVersionNameMethod) {
+            return (String) ReflectionUtil.callMethod(null, androidGetPackageInfoVersionNameMethod, packageName);
+        }
+        return null;
+    }
+    
+    /**
+     * @return null if platform is not Android or no Android Context is registered 
+     *         via {@link jogamp.common.os.android.StaticContext#init(android.content.Context) StaticContext.init(..)}, 
+     *         otherwise the context relative world readable <code>temp</code> directory returned. 
+     */
+    public static File getTempRoot(AccessControlContext acc)
+        throws RuntimeException {
+        if(null != androidGetTempRootMethod) {
+            return (File) ReflectionUtil.callMethod(null, androidGetTempRootMethod, acc);
+        }
+        return null;       
+    }    
+        
+}
diff --git a/src/java/jogamp/common/os/android/PackageInfoUtil.java b/src/java/jogamp/common/os/android/AndroidUtilsImpl.java
index 28795a1..f6a1444 100644
--- a/src/java/jogamp/common/os/android/PackageInfoUtil.java
+++ b/src/java/jogamp/common/os/android/AndroidUtilsImpl.java
@@ -27,11 +27,15 @@
  */
 package jogamp.common.os.android;
 
-import android.content.*;
-import android.content.pm.*;
+import java.io.File;
+import java.security.AccessControlContext;
+
+import android.content.Context;
+import android.content.pm.PackageInfo;
+import android.content.pm.PackageManager;
 import android.util.Log;
 
-public class PackageInfoUtil {
+public class AndroidUtilsImpl {
    private static boolean DEBUG = false;
    
    public static final PackageInfo getPackageInfo(String packageName) {
@@ -53,11 +57,35 @@ public class PackageInfoUtil {
    public static final int getPackageInfoVersionCode(String packageName) {
        final PackageInfo pInfo = getPackageInfo(packageName);
        return ( null != pInfo ) ? pInfo.versionCode : -1 ;
-   }   
+   }
+   
    public static final String getPackageInfoVersionName(String packageName) {
        final PackageInfo pInfo = getPackageInfo(packageName);
        final String s = ( null != pInfo ) ? pInfo.versionName : null ;
        if(DEBUG) Log.d(MD.TAG, "getPackageInfoVersionName("+packageName+"): "+s);
        return s;
-   }   
+   }
+   
+   /**
+    * @return null if no Android Context is registered 
+    *         via {@link jogamp.common.os.android.StaticContext#init(android.content.Context) StaticContext.init(..)}, 
+    *         otherwise the context relative world readable <code>temp</code> directory returned. 
+    */
+   public static File getTempRoot(AccessControlContext acc)
+        throws SecurityException, RuntimeException
+   {
+       final Context ctx = StaticContext.getContext();
+       if(null != ctx) {
+           final File tmpRoot = ctx.getDir("temp", Context.MODE_WORLD_READABLE);
+           if(null==tmpRoot|| !tmpRoot.isDirectory() || !tmpRoot.canWrite()) {
+               throw new RuntimeException("Not a writable directory: '"+tmpRoot+"', retrieved Android static context");
+           }
+           if(DEBUG) {
+               System.err.println("IOUtil.getTempRoot(Android): temp dir: "+tmpRoot.getAbsolutePath());
+           }
+           return tmpRoot;
+       }
+       return null;
+   }
+   
 }
diff --git a/src/java/jogamp/common/os/android/StaticContext.java b/src/java/jogamp/common/os/android/StaticContext.java
index 055fa2f..d7f134a 100644
--- a/src/java/jogamp/common/os/android/StaticContext.java
+++ b/src/java/jogamp/common/os/android/StaticContext.java
@@ -36,7 +36,10 @@ public class StaticContext {
    private static boolean DEBUG = false;
    
    /**
+    * Register Android application context for static usage.
+    * 
     * @param appContext mandatory application Context
+    * @throws RuntimeException if the context is already registered.
     */
    public static final synchronized void init(Context appContext) {
        if(null != StaticContext.appContext) {
@@ -45,10 +48,19 @@ public class StaticContext {
        if(DEBUG) { Log.d(MD.TAG, "init(appCtx "+appContext+")"); }
        StaticContext.appContext = appContext;
    }
+   
+   /**
+    * Unregister the Android application Context
+    */
    public static final synchronized void clear() {
        if(DEBUG) { Log.d(MD.TAG, "clear()"); }
        appContext = null;
    }
+   
+   /**
+    * Return the registered Android application Context
+    * @return
+    */
    public static final synchronized Context getContext() {
        return appContext;
    }