/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.util;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CodingErrorAction;
import java.util.IdentityHashMap;
import java.util.Map;
/**
* A utility class that provides various common operations and constants
* related with {@link Charset} and its relevant classes.
*/
public final class CharsetUtil {
/**
* 16-bit UTF (UCS Transformation Format) whose byte order is identified by
* an optional byte-order mark
*/
public static final Charset UTF_16 = Charset.forName("UTF-16");
/**
* 16-bit UTF (UCS Transformation Format) whose byte order is big-endian
*/
public static final Charset UTF_16BE = Charset.forName("UTF-16BE");
/**
* 16-bit UTF (UCS Transformation Format) whose byte order is little-endian
*/
public static final Charset UTF_16LE = Charset.forName("UTF-16LE");
/**
* 8-bit UTF (UCS Transformation Format)
*/
public static final Charset UTF_8 = Charset.forName("UTF-8");
/**
* ISO Latin Alphabet No. 1, as known as <tt>ISO-LATIN-1</tt>
*/
public static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
/**
* 7-bit ASCII, as known as ISO646-US or the Basic Latin block of the
* Unicode character set
*/
public static final Charset US_ASCII = Charset.forName("US-ASCII");
private static final ThreadLocal<Map<Charset, CharsetEncoder>> encoders =
new ThreadLocal<Map<Charset, CharsetEncoder>>() {
@Override
protected Map<Charset, CharsetEncoder> initialValue() {
return new IdentityHashMap<Charset, CharsetEncoder>();
}
};
private static final ThreadLocal<Map<Charset, CharsetDecoder>> decoders =
new ThreadLocal<Map<Charset, CharsetDecoder>>() {
@Override
protected Map<Charset, CharsetDecoder> initialValue() {
return new IdentityHashMap<Charset, CharsetDecoder>();
}
};
/**
* Returns a cached thread-local {@link CharsetEncoder} for the specified
* <tt>charset</tt>.
*/
public static CharsetEncoder getEncoder(Charset charset) {
if (charset == null) {
throw new NullPointerException("charset");
}
Map<Charset, CharsetEncoder> map = encoders.get();
CharsetEncoder e = map.get(charset);
if (e != null) {
e.reset();
e.onMalformedInput(CodingErrorAction.REPLACE);
e.onUnmappableCharacter(CodingErrorAction.REPLACE);
return e;
}
e = charset.newEncoder();
e.onMalformedInput(CodingErrorAction.REPLACE);
e.onUnmappableCharacter(CodingErrorAction.REPLACE);
map.put(charset, e);
return e;
}
/**
* Returns a cached thread-local {@link CharsetDecoder} for the specified
* <tt>charset</tt>.
*/
public static CharsetDecoder getDecoder(Charset charset) {
if (charset == null) {
throw new NullPointerException("charset");
}
Map<Charset, CharsetDecoder> map = decoders.get();
CharsetDecoder d = map.get(charset);
if (d != null) {
d.reset();
d.onMalformedInput(CodingErrorAction.REPLACE);
d.onUnmappableCharacter(CodingErrorAction.REPLACE);
return d;
}
d = charset.newDecoder();
d.onMalformedInput(CodingErrorAction.REPLACE);
d.onUnmappableCharacter(CodingErrorAction.REPLACE);
map.put(charset, d);
return d;
}
private CharsetUtil() {
// Unused
}
}