org.apache.lucene.store.RAMFile.java Source code

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Here is the source code for org.apache.lucene.store.RAMFile.java

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/*
 * 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.lucene.store;

import java.util.ArrayList;
import java.util.Arrays;

import org.apache.lucene.util.Accountable;

/** 
 * Represents a file in RAM as a list of byte[] buffers.
 * 
 * @lucene.internal 
 * @deprecated This class uses inefficient synchronization and is discouraged
 * in favor of {@link MMapDirectory}. It will be removed in future versions 
 * of Lucene.
 */
@Deprecated
public class RAMFile implements Accountable {
    protected final ArrayList<byte[]> buffers = new ArrayList<>();
    long length;
    RAMDirectory directory;
    protected long sizeInBytes;

    // File used as buffer, in no RAMDirectory
    public RAMFile() {
    }

    RAMFile(RAMDirectory directory) {
        this.directory = directory;
    }

    // For non-stream access from thread that might be concurrent with writing
    public synchronized long getLength() {
        return length;
    }

    protected synchronized void setLength(long length) {
        this.length = length;
    }

    protected final byte[] addBuffer(int size) {
        byte[] buffer = newBuffer(size);
        synchronized (this) {
            buffers.add(buffer);
            sizeInBytes += size;
        }

        if (directory != null) {
            directory.sizeInBytes.getAndAdd(size);
        }
        return buffer;
    }

    protected final synchronized byte[] getBuffer(int index) {
        return buffers.get(index);
    }

    protected final synchronized int numBuffers() {
        return buffers.size();
    }

    /**
     * Expert: allocate a new buffer. 
     * Subclasses can allocate differently. 
     * @param size size of allocated buffer.
     * @return allocated buffer.
     */
    protected byte[] newBuffer(int size) {
        return new byte[size];
    }

    @Override
    public synchronized long ramBytesUsed() {
        return sizeInBytes;
    }

    @Override
    public String toString() {
        return getClass().getSimpleName() + "(length=" + length + ")";
    }

    @Override
    public int hashCode() {
        int h = (int) (length ^ (length >>> 32));
        for (byte[] block : buffers) {
            h = 31 * h + Arrays.hashCode(block);
        }
        return h;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        RAMFile other = (RAMFile) obj;
        if (length != other.length)
            return false;
        if (buffers.size() != other.buffers.size()) {
            return false;
        }
        for (int i = 0; i < buffers.size(); i++) {
            if (!Arrays.equals(buffers.get(i), other.buffers.get(i))) {
                return false;
            }
        }
        return true;
    }
}