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package sun.nio.cs;

import java.nio.charset.*;


Utility class for caching per-thread decoders and encoders.
/** * Utility class for caching per-thread decoders and encoders. */
public class ThreadLocalCoders { private static final int CACHE_SIZE = 3; private static abstract class Cache { // Thread-local reference to array of cached objects, in LRU order private ThreadLocal<Object[]> cache = new ThreadLocal<>(); private final int size; Cache(int size) { this.size = size; } abstract Object create(Object name); private void moveToFront(Object[] oa, int i) { Object ob = oa[i]; for (int j = i; j > 0; j--) oa[j] = oa[j - 1]; oa[0] = ob; } abstract boolean hasName(Object ob, Object name); Object forName(Object name) { Object[] oa = cache.get(); if (oa == null) { oa = new Object[size]; cache.set(oa); } else { for (int i = 0; i < oa.length; i++) { Object ob = oa[i]; if (ob == null) continue; if (hasName(ob, name)) { if (i > 0) moveToFront(oa, i); return ob; } } } // Create a new object Object ob = create(name); oa[oa.length - 1] = ob; moveToFront(oa, oa.length - 1); return ob; } } private static Cache decoderCache = new Cache(CACHE_SIZE) { boolean hasName(Object ob, Object name) { if (name instanceof String) return (((CharsetDecoder)ob).charset().name().equals(name)); if (name instanceof Charset) return ((CharsetDecoder)ob).charset().equals(name); return false; } Object create(Object name) { if (name instanceof String) return Charset.forName((String)name).newDecoder(); if (name instanceof Charset) return ((Charset)name).newDecoder(); assert false; return null; } }; public static CharsetDecoder decoderFor(Object name) { CharsetDecoder cd = (CharsetDecoder)decoderCache.forName(name); cd.reset(); return cd; } private static Cache encoderCache = new Cache(CACHE_SIZE) { boolean hasName(Object ob, Object name) { if (name instanceof String) return (((CharsetEncoder)ob).charset().name().equals(name)); if (name instanceof Charset) return ((CharsetEncoder)ob).charset().equals(name); return false; } Object create(Object name) { if (name instanceof String) return Charset.forName((String)name).newEncoder(); if (name instanceof Charset) return ((Charset)name).newEncoder(); assert false; return null; } }; public static CharsetEncoder encoderFor(Object name) { CharsetEncoder ce = (CharsetEncoder)encoderCache.forName(name); ce.reset(); return ce; } }