Start cleaning up the Charset implementation.

This was going to be https://issues.apache.org/jira/browse/HARMONY-6461,
but I couldn't resist cleaning up some of the surrounding code, and ended
up cleaning up some of our native code too. In the course of the afternoon
I spent on this, I lost my conviction that the upstream change makes
sense, so I reverted that, leaving this change just pure cleanup.

(Note that the cleanup work is incomplete. This is an improvement, but
there's plenty left to do. I just don't want to get too distracted until
all the Java 6 changes are done.)

Change-Id: I56841db5f6c038bbf7942e83a148dca546519269

3 files changed, 36 insertions, 131 deletions

diff --git a/icu/src/main/java/com/ibm/icu4jni/charset/CharsetICU.java b/icu/src/main/java/com/ibm/icu4jni/charset/CharsetICU.java
index df6f7dc..48deb00 100644
--- a/icu/src/main/java/com/ibm/icu4jni/charset/CharsetICU.java
+++ b/icu/src/main/java/com/ibm/icu4jni/charset/CharsetICU.java
@@ -22,7 +22,7 @@ import java.util.Map;
 
 
 public final class CharsetICU extends Charset{
-    private String icuCanonicalName;
+    private final String icuCanonicalName;
     /**
      * Constructor to create a the CharsetICU object
      * @param canonicalName the canonical name as a string
@@ -30,23 +30,18 @@ public final class CharsetICU extends Charset{
      * @stable ICU 2.4
      */
     protected CharsetICU(String canonicalName, String icuCanonName, String[] aliases) {
-         super(canonicalName,aliases);
+         super(canonicalName, aliases);
          icuCanonicalName = icuCanonName;
-        
     }
     /**
      * Returns a new decoder instance of this charset object
      * @return a new decoder object
      * @stable ICU 2.4
      */
-    public CharsetDecoder newDecoder(){
-        // the arrays are locals and not
-        // instance variables since the
-        // methods on this class need to 
-        // be thread safe
+    public CharsetDecoder newDecoder() {
         long converterHandle = NativeConverter.openConverter(icuCanonicalName);
-        return new CharsetDecoderICU(this,converterHandle);
-    };
+        return new CharsetDecoderICU(this, converterHandle);
+    }
     
     // hardCoded list of replacement bytes
     private static final Map subByteMap = new HashMap();
@@ -125,5 +120,3 @@ public final class CharsetICU extends Charset{
         }
     }
 }
-
-
diff --git a/icu/src/main/java/com/ibm/icu4jni/charset/CharsetProviderICU.java b/icu/src/main/java/com/ibm/icu4jni/charset/CharsetProviderICU.java
index 6f63479..0479223 100644
--- a/icu/src/main/java/com/ibm/icu4jni/charset/CharsetProviderICU.java
+++ b/icu/src/main/java/com/ibm/icu4jni/charset/CharsetProviderICU.java
@@ -11,108 +11,40 @@ package com.ibm.icu4jni.charset;
 
 import java.nio.charset.Charset;
 import java.nio.charset.spi.CharsetProvider;
-import java.util.*;
+import java.util.ArrayList;
 import java.util.Iterator;
-// BEGIN android-removed
-// import com.ibm.icu4jni.converters.NativeConverter;
-// END android-removed
+import java.util.SortedMap;
+import java.util.TreeMap;
 
-public final class CharsetProviderICU extends CharsetProvider{
-    
-    /**
-     * Constructs a CharsetProviderICU object 
-     * @stable ICU 2.4
-     */
-    public CharsetProviderICU(){
+public final class CharsetProviderICU extends CharsetProvider {
+    public CharsetProviderICU() {
     }
-    
-    /**
-     * Constructs a charset for the given charset name
-     * @param charsetName charset name
-     * @return charset objet for the given charset name
-     * @stable ICU 2.4
-     */
-    public final Charset charsetForName(String charsetName) {
-        // get the canonical name    
-        String icuCanonicalName = NativeConverter.getICUCanonicalName(charsetName);      
 
-        // create the converter object and return it
-        if(icuCanonicalName==null || icuCanonicalName.length()==0){
-            // this would make the Charset API to throw 
-            // unsupported encoding exception
-            return null;
-        }
-        
-        // BEGIN android-added
-        try{
-            long cn = NativeConverter.openConverter(icuCanonicalName);
-            NativeConverter.closeConverter(cn);
-        }catch (RuntimeException re) {
-            // unsupported encoding. let the charset api throw an 
-            // UnsupportedEncodingException
-            return null;
-        }
-        // END android-added
-        
-        return getCharset(icuCanonicalName);
-    }
-    private final Charset getCharset(String icuCanonicalName){
-       String[] aliases = (String[])NativeConverter.getAliases(icuCanonicalName);    
-       String canonicalName = NativeConverter.getJavaCanonicalName(icuCanonicalName);
-       return (new CharsetICU(canonicalName,icuCanonicalName, aliases));  
+    @Override
+    public Charset charsetForName(String charsetName) {
+        return NativeConverter.charsetForName(charsetName);
     }
-    /**
-     * Adds an entry to the given map whose key is the charset's 
-     * canonical name and whose value is the charset itself. 
-     * @param map a map to receive charset objects and names
-     * @stable ICU 2.4
-     */
-    public final void putCharsets(Map map) {
-        // Get the available converter canonical names and aliases    
-        String[] charsets = NativeConverter.getAvailable();        
-        for(int i=0; i<charsets.length;i++){           
-            // store the charsets and aliases in a Map    
-            if (!map.containsKey(charsets[i])){
-                map.put(charsets[i], charsetForName(charsets[i]));
-            }
-        }
-    }
-    /**
-     * Class that implements the iterator for charsets
-     * @stable ICU 2.4
-     */
-    protected final class CharsetIterator implements Iterator{
-      private String[] names;
-      private int currentIndex;
-      protected CharsetIterator(String[] strs){
-        names = strs;
-        currentIndex=0;
-      }
-      public boolean hasNext(){
-        return (currentIndex< names.length);
-      }
-      public Object next(){
-        if(currentIndex<names.length){
-              return charsetForName(names[currentIndex++]);
-        }else{
-              throw new NoSuchElementException();
+
+    @Override
+    public Iterator<Charset> charsets() {
+        ArrayList<Charset> result = new ArrayList<Charset>();
+        for (String charsetName : NativeConverter.getAvailable()) {
+            result.add(charsetForName(charsetName));
         }
-      }
-      public void remove() {
-            throw new UnsupportedOperationException();
-      }
+        return result.iterator();
     }
-      
 
     /**
-     * Returns an iterator for the available charsets
-     * @return Iterator the charset name iterator
-     * @stable ICU 2.4
+     * Implements Charset.availableCharsets.
      */
-    public final Iterator charsets(){
-          String[] charsets = NativeConverter.getAvailable();
-          Iterator iter = new CharsetIterator(charsets);
-          return iter;
+    public SortedMap<String, Charset> initAvailableCharsets() {
+        SortedMap<String, Charset> result =
+                new TreeMap<String, Charset>(String.CASE_INSENSITIVE_ORDER);
+        for (String charset : NativeConverter.getAvailable()) {
+            if (!result.containsKey(charset)) {
+                result.put(charset, charsetForName(charset));
+            }
+        }
+        return result;
     }
-     
 }
diff --git a/icu/src/main/java/com/ibm/icu4jni/charset/NativeConverter.java b/icu/src/main/java/com/ibm/icu4jni/charset/NativeConverter.java
index 9af63ee..eefe3d5 100644
--- a/icu/src/main/java/com/ibm/icu4jni/charset/NativeConverter.java
+++ b/icu/src/main/java/com/ibm/icu4jni/charset/NativeConverter.java
@@ -9,11 +9,13 @@
 
 package com.ibm.icu4jni.charset;
 
+import java.nio.charset.Charset;
+
 /**
  * Class for accessing the underlying JNI methods
  * @internal ICU 2.4
  */
-final class NativeConverter{
+final class NativeConverter {
   
     //Native methods
     
@@ -335,7 +337,9 @@ final class NativeConverter{
      * @internal ICU 2.4
      */
     public static final native String[] getAvailable();
-    
+
+    public static final native Charset charsetForName(String charsetName);
+
     /**
      * Gets the number of aliases for a converter name
      * @param enc encoding name
@@ -353,30 +357,6 @@ final class NativeConverter{
     public static final native String[] getAliases(String enc);
     
     /**
-     * Gets the canonical name of the converter
-     * @param enc converter name
-     * @return canonical name of the converter
-     * @internal ICU 2.4
-     */
-    public static final native String getCanonicalName(String enc);
-    
-    /**
-     * Gets the canonical name of the converter as defined by Java
-     * @param enc converter name
-     * @return canonical name of the converter
-     * @internal ICU 3.4
-     */
-    public static final native String getICUCanonicalName(String enc);
-      
-    /**
-     * Gets the canonical name of the converter as defined by Java
-     * @param icuCanonicalName converter name
-     * @return canonical name of the converter
-     * @internal ICU 3.4
-     */
-    public static final native String getJavaCanonicalName(String icuCanonicalName);
-    
-    /**
      * Sets the callback to Unicode for ICU conveter. The default behaviour of ICU callback
      * is to call the specified callback function for both illegal and unmapped sequences.
      * @param converterHandle Adress of the converter object created by native code