71 lines
2.7 KiB
Java
71 lines
2.7 KiB
Java
/*
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* Copyright (C) 2011 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy of
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* the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations under
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* the License.
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*/
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package com.android.inputmethod.latin;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.List;
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/**
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* A pool of string builders to be used from anywhere.
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*/
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public class StringBuilderPool {
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// Singleton
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private static final StringBuilderPool sInstance = new StringBuilderPool();
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private static final boolean DEBUG = false;
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private StringBuilderPool() {}
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// TODO: Make this a normal array with a size of 20, or a ConcurrentQueue
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private final List<StringBuilder> mPool =
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Collections.synchronizedList(new ArrayList<StringBuilder>());
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public static StringBuilder getStringBuilder(final int initialSize) {
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// TODO: although the pool is synchronized, the following is not thread-safe.
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// Two threads entering this at the same time could take the same size of the pool and the
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// second to attempt removing this index from the pool would crash with an
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// IndexOutOfBoundsException.
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// At the moment this pool is only used in Suggest.java and only in one thread so it's
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// okay. The simplest thing to do here is probably to replace the ArrayList with a
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// ConcurrentQueue.
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final int poolSize = sInstance.mPool.size();
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final StringBuilder sb = poolSize > 0 ? (StringBuilder) sInstance.mPool.remove(poolSize - 1)
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: new StringBuilder(initialSize);
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sb.setLength(0);
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return sb;
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}
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public static void recycle(final StringBuilder garbage) {
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if (DEBUG) {
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final int gid = garbage.hashCode();
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for (final StringBuilder q : sInstance.mPool) {
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if (gid == q.hashCode()) throw new RuntimeException("Duplicate id " + gid);
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}
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}
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sInstance.mPool.add(garbage);
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}
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public static void ensureCapacity(final int capacity, final int initialSize) {
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for (int i = sInstance.mPool.size(); i < capacity; ++i) {
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final StringBuilder sb = new StringBuilder(initialSize);
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sInstance.mPool.add(sb);
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}
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}
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public static int getSize() {
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return sInstance.mPool.size();
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}
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}
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