Add CharsetUtil.encoder/decoder() methods

Motivation:

See #3321

Modifications:

1. Add CharsetUtil.encoder/decoder() methods
2. Deprecate CharsetUtil.getEncoder/getDecoder() methods

Result:

Users can use new CharsetUtil.encoder/decoder() to specify error actions

buffer/src/main/java/io/netty/buffer/ByteBufUtil.java

@@ -61,7 +61,7 @@ public final class ByteBufUtil {
     private static final int MAX_CHAR_BUFFER_SIZE;
     private static final int THREAD_LOCAL_BUFFER_SIZE;
     private static final int MAX_BYTES_PER_CHAR_UTF8 =
-            (int) CharsetUtil.getEncoder(CharsetUtil.UTF_8).maxBytesPerChar();
+            (int) CharsetUtil.encoder(CharsetUtil.UTF_8).maxBytesPerChar();
 
     static final ByteBufAllocator DEFAULT_ALLOCATOR;
 
@@ -511,7 +511,7 @@ public final class ByteBufUtil {
     }
 
     static ByteBuf encodeString0(ByteBufAllocator alloc, boolean enforceHeap, CharBuffer src, Charset charset) {
-        final CharsetEncoder encoder = CharsetUtil.getEncoder(charset);
+        final CharsetEncoder encoder = CharsetUtil.encoder(charset);
         int length = (int) ((double) src.remaining() * encoder.maxBytesPerChar());
         boolean release = true;
         final ByteBuf dst;
@@ -547,7 +547,7 @@ public final class ByteBufUtil {
         if (len == 0) {
             return StringUtil.EMPTY_STRING;
         }
-        final CharsetDecoder decoder = CharsetUtil.getDecoder(charset);
+        final CharsetDecoder decoder = CharsetUtil.decoder(charset);
         final int maxLength = (int) ((double) len * decoder.maxCharsPerByte());
         CharBuffer dst = CHAR_BUFFERS.get();
         if (dst.length() < maxLength) {

codec-socks/src/main/java/io/netty/handler/codec/socks/SocksAuthRequest.java

@@ -27,7 +27,7 @@ import java.nio.charset.CharsetEncoder;
  * @see SocksAuthRequestDecoder
  */
 public final class SocksAuthRequest extends SocksRequest {
-    private static final CharsetEncoder asciiEncoder = CharsetUtil.getEncoder(CharsetUtil.US_ASCII);
+    private static final CharsetEncoder asciiEncoder = CharsetUtil.encoder(CharsetUtil.US_ASCII);
     private static final SocksSubnegotiationVersion SUBNEGOTIATION_VERSION = SocksSubnegotiationVersion.AUTH_PASSWORD;
     private final String username;
     private final String password;

common/src/main/java/io/netty/util/AsciiString.java

@@ -194,7 +194,7 @@ public final class AsciiString implements CharSequence, Comparable<CharSequence>
      */
     public AsciiString(char[] value, Charset charset, int start, int length) {
         CharBuffer cbuf = CharBuffer.wrap(value, start, length);
-        CharsetEncoder encoder = CharsetUtil.getEncoder(charset);
+        CharsetEncoder encoder = CharsetUtil.encoder(charset);
         ByteBuffer nativeBuffer = ByteBuffer.allocate((int) (encoder.maxBytesPerChar() * length));
         encoder.encode(cbuf, nativeBuffer, true);
         final int bufferOffset = nativeBuffer.arrayOffset();
@@ -241,7 +241,7 @@ public final class AsciiString implements CharSequence, Comparable<CharSequence>
      */
     public AsciiString(CharSequence value, Charset charset, int start, int length) {
         CharBuffer cbuf = CharBuffer.wrap(value, start, start + length);
-        CharsetEncoder encoder = CharsetUtil.getEncoder(charset);
+        CharsetEncoder encoder = CharsetUtil.encoder(charset);
         ByteBuffer nativeBuffer = ByteBuffer.allocate((int) (encoder.maxBytesPerChar() * length));
         encoder.encode(cbuf, nativeBuffer, true);
         final int offset = nativeBuffer.arrayOffset();

common/src/main/java/io/netty/util/CharsetUtil.java

@@ -16,6 +16,7 @@
 package io.netty.util;
 
 import io.netty.util.internal.InternalThreadLocalMap;
+import static io.netty.util.internal.ObjectUtil.checkNotNull;
 
 import java.nio.charset.Charset;
 import java.nio.charset.CharsetDecoder;
@@ -67,51 +68,113 @@ public final class CharsetUtil {
     public static Charset[] values() { return CHARSETS; }
 
     /**
-     * Returns a cached thread-local {@link CharsetEncoder} for the specified
+     * @deprecated Use {@link #encoder(Charset)}.
-     * <tt>charset</tt>.
      */
+    @Deprecated
     public static CharsetEncoder getEncoder(Charset charset) {
-        if (charset == null) {
+        return encoder(charset);
-            throw new NullPointerException("charset");
     }
 
+    /**
+     * Returns a new {@link CharsetEncoder} for the {@link Charset} with specified error actions.
+     *
+     * @param charset The specified charset
+     * @param malformedInputAction The encoder's action for malformed-input errors
+     * @param unmappableCharacterAction The encoder's action for unmappable-character errors
+     * @return The encoder for the specified <code>charset</code>
+     */
+    public static CharsetEncoder encoder(Charset charset, CodingErrorAction malformedInputAction,
+                                         CodingErrorAction unmappableCharacterAction) {
+        checkNotNull(charset, "charset");
+        CharsetEncoder e = charset.newEncoder();
+        e.onMalformedInput(malformedInputAction).onUnmappableCharacter(unmappableCharacterAction);
+        return e;
+    }
+
+    /**
+     * Returns a new {@link CharsetEncoder} for the {@link Charset} with the specified error action.
+     *
+     * @param charset The specified charset
+     * @param codingErrorAction The encoder's action for malformed-input and unmappable-character errors
+     * @return The encoder for the specified <code>charset</code>
+     */
+    public static CharsetEncoder encoder(Charset charset, CodingErrorAction codingErrorAction) {
+        return encoder(charset, codingErrorAction, codingErrorAction);
+    }
+
+    /**
+     * Returns a cached thread-local {@link CharsetEncoder} for the specified {@link Charset}.
+     *
+     * @param charset The specified charset
+     * @return The encoder for the specified <code>charset</code>
+     */
+    public static CharsetEncoder encoder(Charset charset) {
+        checkNotNull(charset, "charset");
+
         Map<Charset, CharsetEncoder> map = InternalThreadLocalMap.get().charsetEncoderCache();
         CharsetEncoder e = map.get(charset);
         if (e != null) {
-            e.reset();
+            e.reset().onMalformedInput(CodingErrorAction.REPLACE).onUnmappableCharacter(CodingErrorAction.REPLACE);
-            e.onMalformedInput(CodingErrorAction.REPLACE);
-            e.onUnmappableCharacter(CodingErrorAction.REPLACE);
             return e;
         }
 
-        e = charset.newEncoder();
+        e = encoder(charset, CodingErrorAction.REPLACE, CodingErrorAction.REPLACE);
-        e.onMalformedInput(CodingErrorAction.REPLACE);
-        e.onUnmappableCharacter(CodingErrorAction.REPLACE);
         map.put(charset, e);
         return e;
     }
 
     /**
-     * Returns a cached thread-local {@link CharsetDecoder} for the specified
+     * @deprecated Use {@link #decoder(Charset)}.
-     * <tt>charset</tt>.
      */
+    @Deprecated
     public static CharsetDecoder getDecoder(Charset charset) {
-        if (charset == null) {
+        return decoder(charset);
-            throw new NullPointerException("charset");
     }
 
+    /**
+     * Returns a new {@link CharsetDecoder} for the {@link Charset} with specified error actions.
+     *
+     * @param charset The specified charset
+     * @param malformedInputAction The decoder's action for malformed-input errors
+     * @param unmappableCharacterAction The decoder's action for unmappable-character errors
+     * @return The decoder for the specified <code>charset</code>
+     */
+    public static CharsetDecoder decoder(Charset charset, CodingErrorAction malformedInputAction,
+                                         CodingErrorAction unmappableCharacterAction) {
+        checkNotNull(charset, "charset");
+        CharsetDecoder d = charset.newDecoder();
+        d.onMalformedInput(malformedInputAction).onUnmappableCharacter(unmappableCharacterAction);
+        return d;
+    }
+
+    /**
+     * Returns a new {@link CharsetDecoder} for the {@link Charset} with the specified error action.
+     *
+     * @param charset The specified charset
+     * @param codingErrorAction The decoder's action for malformed-input and unmappable-character errors
+     * @return The decoder for the specified <code>charset</code>
+     */
+    public static CharsetDecoder decoder(Charset charset, CodingErrorAction codingErrorAction) {
+        return decoder(charset, codingErrorAction, codingErrorAction);
+    }
+
+    /**
+     * Returns a cached thread-local {@link CharsetDecoder} for the specified {@link Charset}.
+     *
+     * @param charset The specified charset
+     * @return The decoder for the specified <code>charset</code>
+     */
+    public static CharsetDecoder decoder(Charset charset) {
+        checkNotNull(charset, "charset");
+
         Map<Charset, CharsetDecoder> map = InternalThreadLocalMap.get().charsetDecoderCache();
         CharsetDecoder d = map.get(charset);
         if (d != null) {
-            d.reset();
+            d.reset().onMalformedInput(CodingErrorAction.REPLACE).onUnmappableCharacter(CodingErrorAction.REPLACE);
-            d.onMalformedInput(CodingErrorAction.REPLACE);
-            d.onUnmappableCharacter(CodingErrorAction.REPLACE);
             return d;
         }
 
-        d = charset.newDecoder();
+        d = decoder(charset, CodingErrorAction.REPLACE, CodingErrorAction.REPLACE);
-        d.onMalformedInput(CodingErrorAction.REPLACE);
-        d.onUnmappableCharacter(CodingErrorAction.REPLACE);
         map.put(charset, d);
         return d;
     }