LatinIME/java/src/com/android/inputmethod/latin/StringBuilderPool.java
Jean Chalard a6e912cf98 Fix a bug with the string pool.
This also adds some optional debug code to detect more easily possible
future occurrences of the same problem.

Bug: 5195017
Change-Id: I2558b468e46f7090de868f1ec2dc9e24895d670f
2011-08-23 14:55:34 +09:00

70 lines
2.7 KiB
Java

/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed 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 com.android.inputmethod.latin;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/**
* A pool of string builders to be used from anywhere.
*/
public class StringBuilderPool {
// Singleton
private static final StringBuilderPool sInstance = new StringBuilderPool();
private static final boolean DEBUG = false;
private StringBuilderPool() {}
// TODO: Make this a normal array with a size of 20, or a ConcurrentQueue
private final List<StringBuilder> mPool =
Collections.synchronizedList(new ArrayList<StringBuilder>());
public static StringBuilder getStringBuilder(final int initialSize) {
// TODO: although the pool is synchronized, the following is not thread-safe.
// Two threads entering this at the same time could take the same size of the pool and the
// second to attempt removing this index from the pool would crash with an
// IndexOutOfBoundsException.
// At the moment this pool is only used in Suggest.java and only in one thread so it's
// okay. The simplest thing to do here is probably to replace the ArrayList with a
// ConcurrentQueue.
final int poolSize = sInstance.mPool.size();
final StringBuilder sb = poolSize > 0 ? (StringBuilder) sInstance.mPool.remove(poolSize - 1)
: new StringBuilder(initialSize);
sb.setLength(0);
return sb;
}
public static void recycle(final StringBuilder garbage) {
if (DEBUG) {
final int gid = garbage.hashCode();
for (final StringBuilder q : sInstance.mPool) {
if (gid == q.hashCode()) throw new RuntimeException("Duplicate id " + gid);
}
}
sInstance.mPool.add(garbage);
}
public static void ensureCapacity(final int capacity, final int initialSize) {
for (int i = sInstance.mPool.size(); i < capacity; ++i) {
final StringBuilder sb = new StringBuilder(initialSize);
sInstance.mPool.add(sb);
}
}
public static int getSize() {
return sInstance.mPool.size();
}
}