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/*
* Copyright 2000-2013 JetBrains s.r.o.
*
* 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.intellij.util;
import com.intellij.util.containers.IntObjectLinkedMap;
import org.jetbrains.annotations.Nullable;
/**
* @author peter
*/
public class IntSLRUCache<Entry extends IntObjectLinkedMap.MapEntry> {
private static final boolean ourPrintDebugStatistics = false;
private final IntObjectLinkedMap<Entry> myProtectedQueue;
private final IntObjectLinkedMap<Entry> myProbationalQueue;
private int probationalHits = 0;
private int protectedHits = 0;
private int misses = 0;
public IntSLRUCache(int protectedQueueSize, int probationalQueueSize) {
myProtectedQueue = new IntObjectLinkedMap<Entry>(protectedQueueSize);
myProbationalQueue = new IntObjectLinkedMap<Entry>(probationalQueueSize);
}
public Entry cacheEntry(final Entry entry) {
Entry cached = myProtectedQueue.getEntry(entry.key);
if (cached == null) {
cached = myProbationalQueue.getEntry(entry.key);
}
if (cached != null) {
return cached;
}
myProbationalQueue.putEntry(entry);
return entry;
}
@Nullable
public Entry getCachedEntry(int id) {
return getCachedEntry(id, true);
}
@Nullable
public Entry getCachedEntry(int id, boolean allowMutation) {
Entry entry = myProtectedQueue.getEntry(id);
if (entry != null) {
protectedHits++;
return entry;
}
entry = myProbationalQueue.getEntry(id);
if (entry != null) {
printStatistics(++probationalHits);
if (allowMutation) {
myProbationalQueue.removeEntry(entry.key);
Entry demoted = myProtectedQueue.putEntry(entry);
if (demoted != null) {
myProbationalQueue.putEntry(demoted);
}
}
return entry;
}
printStatistics(++misses);
return null;
}
private void printStatistics(int hits) {
//noinspection ConstantConditions
if (ourPrintDebugStatistics && hits % 1000 == 0) {
//noinspection UseOfSystemOutOrSystemErr
System.out.println("IntSLRUCache.getCachedEntry time " + System.currentTimeMillis() +
", prot=" + protectedHits + ", prob=" + probationalHits + ", misses=" + misses);
}
}
}
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