/**
* 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.activemq.kaha.impl.data;
import java.io.IOException;
import java.io.RandomAccessFile;
import org.apache.activemq.kaha.Marshaller;
import org.apache.activemq.kaha.StoreLocation;
import org.apache.activemq.util.DataByteArrayInputStream;
/**
* Optimized Store reader
*
* @version $Revision: 1.1.1.1 $
*/
public final class SyncDataFileReader {
private DataManagerImpl dataManager;
private DataByteArrayInputStream dataIn;
/**
* Construct a Store reader
*
* @param fileId
*/
SyncDataFileReader(DataManagerImpl fileManager) {
this.dataManager = fileManager;
this.dataIn = new DataByteArrayInputStream();
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.kaha.impl.data.DataFileReader#readDataItemSize(org.apache.activemq.kaha.impl.data.DataItem)
*/
public synchronized byte readDataItemSize(DataItem item) throws IOException {
RandomAccessFile file = dataManager.getDataFile(item).getRandomAccessFile();
file.seek(item.getOffset()); // jump to the size field
byte rc = file.readByte();
item.setSize(file.readInt());
return rc;
}
/*
* (non-Javadoc)
*
* @see org.apache.activemq.kaha.impl.data.DataFileReader#readItem(org.apache.activemq.kaha.Marshaller,
* org.apache.activemq.kaha.StoreLocation)
*/
public synchronized Object readItem(Marshaller marshaller, StoreLocation item) throws IOException {
RandomAccessFile file = dataManager.getDataFile(item).getRandomAccessFile();
// TODO: we could reuse the buffer in dataIn if it's big enough to avoid
// allocating byte[] arrays on every readItem.
byte[] data = new byte[item.getSize()];
file.seek(item.getOffset() + DataManagerImpl.ITEM_HEAD_SIZE);
file.readFully(data);
dataIn.restart(data);
return marshaller.readPayload(dataIn);
}
}