/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.blur.store.blockcache_v2.cachevalue;
import static org.apache.blur.metrics.MetricsConstants.CACHE;
import static org.apache.blur.metrics.MetricsConstants.DETACHES;
import static org.apache.blur.metrics.MetricsConstants.ORG_APACHE_BLUR;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.blur.store.blockcache_v2.CacheValue;
import com.yammer.metrics.Metrics;
import com.yammer.metrics.core.Meter;
import com.yammer.metrics.core.MetricName;
@SuppressWarnings("serial")
public class DetachableCacheValue extends AtomicInteger implements CacheValue {
private static final Meter _detaches;
static {
_detaches = Metrics.newMeter(new MetricName(ORG_APACHE_BLUR, CACHE, DETACHES), DETACHES, TimeUnit.SECONDS);
}
private volatile CacheValue _baseCacheValue;
public DetachableCacheValue(CacheValue cacheValue) {
_baseCacheValue = cacheValue;
}
@Override
public CacheValue detachFromCache() {
if (_baseCacheValue instanceof ByteArrayCacheValue) {
// already detached
return null;
} else if (_baseCacheValue instanceof UnsafeCacheValue) {
final CacheValue result = _baseCacheValue;
if (get() == 0) {
// No one is using this so don't copy
// NULL out reference so just in case there can't be a seg fault.
_baseCacheValue = null;
} else {
// Copy data, because someone might access at some point
_detaches.mark();
int length = _baseCacheValue.length();
ByteArrayCacheValue byteArrayCacheValue = new ByteArrayCacheValue(length);
_baseCacheValue.read(0, byteArrayCacheValue._buffer, 0, length);
_baseCacheValue = byteArrayCacheValue;
}
return result;
} else {
throw new RuntimeException("Unsupported type of [" + _baseCacheValue + "]");
}
}
@Override
public int length() {
return _baseCacheValue.length();
}
@Override
public void write(int position, byte[] buf, int offset, int length) {
_baseCacheValue.write(position, buf, offset, length);
}
@Override
public void read(int position, byte[] buf, int offset, int length) {
_baseCacheValue.read(position, buf, offset, length);
}
@Override
public byte read(int position) {
return _baseCacheValue.read(position);
}
@Override
public void release() {
_baseCacheValue.release();
}
@Override
public short readShort(int position) {
return _baseCacheValue.readShort(position);
}
@Override
public int readInt(int position) {
return _baseCacheValue.readInt(position);
}
@Override
public long readLong(int position) {
return _baseCacheValue.readLong(position);
}
@Override
public CacheValue trim(int length) {
return this;
}
@Override
public void decRef() {
decrementAndGet();
}
@Override
public void incRef() {
incrementAndGet();
}
}