/*
* @(#)$Id: codetemplate_xbird.xml 943 2006-09-13 07:03:37Z yui $
*
* Copyright 2006-2008 Makoto YUI
*
* 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.
*
* Contributors:
* Makoto YUI - initial implementation
*/
package xbird.storage.io;
import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import xbird.util.cache.Cleaner;
import xbird.util.cache.ICacheEntry;
import xbird.util.cache.ILongCache;
import xbird.util.codec.Codec;
import xbird.util.concurrent.cache.ConcurrentLongCache;
/**
*
* <DIV lang="en"></DIV> <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
*/
public final class DiskPagedLongCache<V> implements ILongCache<V>, Cleaner<Long, V>, Closeable {
private static final long serialVersionUID = 4361712313780427720L;
private final VarSegments paged;
private ILongCache<V> internalCache;
private final Codec<V> codec;
@SuppressWarnings("unchecked")
public DiskPagedLongCache(File file, int cacheSize, Codec<V> codec) {
if(!file.exists()) {
throw new IllegalStateException("File does not exists: " + file.getAbsolutePath());
}
this.paged = new VarSegments(file, cacheSize);
this.internalCache = new ConcurrentLongCache(cacheSize, this);
this.codec = codec;
}
public void clear() {
internalCache.clear();
}
public V get(long key) {
final V cached = internalCache.get(key);
if(cached != null) {
return cached;
}
final byte[] b;
try {
b = paged.read(key);
} catch (IOException e) {
throw new IllegalStateException(e);
}
if(b == null) {
return null;
}
final V decoded = codec.decode(b);
internalCache.put(key, decoded);
return decoded;
}
public V put(long key, V value) {
return internalCache.put(key, value);
}
public V putIfAbsent(long key, V value) {
throw new UnsupportedOperationException();
}
public void cleanup(Long key, V value) {
assert (value != null) : key;
final byte[] b = codec.encode(value);
try {
paged.writeIfAbsent(key.longValue(), b);
} catch (IOException e) {
;
}
}
public void close() throws IOException {
this.internalCache = null;
paged.delete();
}
public ICacheEntry<Long, V> fixEntry(long key) {
throw new UnsupportedOperationException();
}
}