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ActiveMQ example source code file (BitArray.java)

This example ActiveMQ source code file (BitArray.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - ActiveMQ tags/keywords

bit_values, bit_values, bitarray, byte_size, classnotfoundexception, int_size, int_size, io, ioexception, ioexception, long_size, serializable, short_size, short_size

The ActiveMQ BitArray.java source code

/**
 * 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.util;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.Serializable;

/**
 * Simple BitArray to enable setting multiple boolean values efficently Used
 * instead of BitSet because BitSet does not allow for efficent serialization.
 * Will store up to 64 boolean values
 * 
 * 
 */
public class BitArray implements Serializable {
    
    private static final long serialVersionUID = 1L;
    
    static final int LONG_SIZE = 64;
    static final int INT_SIZE = 32;
    static final int SHORT_SIZE = 16;
    static final int BYTE_SIZE = 8;
    private static final long[] BIT_VALUES = {0x0000000000000001L, 0x0000000000000002L, 0x0000000000000004L,
                                              0x0000000000000008L, 0x0000000000000010L, 0x0000000000000020L,
                                              0x0000000000000040L, 0x0000000000000080L, 0x0000000000000100L,
                                              0x0000000000000200L, 0x0000000000000400L, 0x0000000000000800L,
                                              0x0000000000001000L, 0x0000000000002000L, 0x0000000000004000L,
                                              0x0000000000008000L, 0x0000000000010000L, 0x0000000000020000L,
                                              0x0000000000040000L, 0x0000000000080000L, 0x0000000000100000L,
                                              0x0000000000200000L, 0x0000000000400000L, 0x0000000000800000L,
                                              0x0000000001000000L, 0x0000000002000000L, 0x0000000004000000L,
                                              0x0000000008000000L, 0x0000000010000000L, 0x0000000020000000L,
                                              0x0000000040000000L, 0x0000000080000000L, 0x0000000100000000L,
                                              0x0000000200000000L, 0x0000000400000000L, 0x0000000800000000L,
                                              0x0000001000000000L, 0x0000002000000000L, 0x0000004000000000L,
                                              0x0000008000000000L, 0x0000010000000000L, 0x0000020000000000L,
                                              0x0000040000000000L, 0x0000080000000000L, 0x0000100000000000L,
                                              0x0000200000000000L, 0x0000400000000000L, 0x0000800000000000L,
                                              0x0001000000000000L, 0x0002000000000000L, 0x0004000000000000L,
                                              0x0008000000000000L, 0x0010000000000000L, 0x0020000000000000L,
                                              0x0040000000000000L, 0x0080000000000000L, 0x0100000000000000L,
                                              0x0200000000000000L, 0x0400000000000000L, 0x0800000000000000L,
                                              0x1000000000000000L, 0x2000000000000000L, 0x4000000000000000L,
                                              0x8000000000000000L};
    private long bits;
    private int length;

    /**
     * @return the length of bits set
     */
    public int length() {
        return length;
    }

    /**
     * @return the long containing the bits
     */
    public long getBits() {
        return bits;
    }

    /**
     * set the boolean value at the index
     * 
     * @param index
     * @param flag
     * @return the old value held at this index
     */
    public boolean set(int index, boolean flag) {
        length = Math.max(length, index + 1);
        boolean oldValue = (bits & BIT_VALUES[index]) != 0;
        if (flag) {
            bits |= BIT_VALUES[index];
        } else if (oldValue) {
            bits &= ~(BIT_VALUES[index]);
        }
        return oldValue;
    }

    /**
     * @param index
     * @return the boolean value at this index
     */
    public boolean get(int index) {
        return (bits & BIT_VALUES[index]) != 0;
    }

    /**
     * reset all the bit values to false
     */
    public void reset() {
        bits = 0;
    }

    /**
     * reset all the bits to the value supplied
     * 
     * @param bits
     */
    public void reset(long bits) {
        this.bits = bits;
    }

    private void writeObject(java.io.ObjectOutputStream out) throws IOException {
        writeToStream(out);
    }
    
    private void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException {
        readFromStream(in);
    }
    
    /**
     * write the bits to an output stream
     * 
     * @param dataOut
     * @throws IOException
     */
    public void writeToStream(DataOutput dataOut) throws IOException {
        dataOut.writeByte(length);
        if (length <= BYTE_SIZE) {
            dataOut.writeByte((int)bits);
        } else if (length <= SHORT_SIZE) {
            dataOut.writeShort((short)bits);
        } else if (length <= INT_SIZE) {
            dataOut.writeInt((int)bits);
        } else {
            dataOut.writeLong(bits);
        }
    }

    /**
     * read the bits from an input stream
     * 
     * @param dataIn
     * @throws IOException
     */
    public void readFromStream(DataInput dataIn) throws IOException {
        length = dataIn.readByte();
        if (length <= BYTE_SIZE) {
            bits = dataIn.readByte();
        } else if (length <= SHORT_SIZE) {
            bits = dataIn.readShort();
        } else if (length <= INT_SIZE) {
            bits = dataIn.readInt();
        } else {
            bits = dataIn.readLong();
        }
    }
}

Other ActiveMQ examples (source code examples)

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