001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.activemq.util; 018 019import java.io.DataInput; 020import java.io.DataOutput; 021import java.io.IOException; 022import java.io.Serializable; 023 024/** 025 * Simple BitArray to enable setting multiple boolean values efficently Used 026 * instead of BitSet because BitSet does not allow for efficent serialization. 027 * Will store up to 64 boolean values 028 * 029 * 030 */ 031public class BitArray implements Serializable { 032 033 private static final long serialVersionUID = 1L; 034 035 static final int LONG_SIZE = 64; 036 static final int INT_SIZE = 32; 037 static final int SHORT_SIZE = 16; 038 static final int BYTE_SIZE = 8; 039 private static final long[] BIT_VALUES = {0x0000000000000001L, 0x0000000000000002L, 0x0000000000000004L, 040 0x0000000000000008L, 0x0000000000000010L, 0x0000000000000020L, 041 0x0000000000000040L, 0x0000000000000080L, 0x0000000000000100L, 042 0x0000000000000200L, 0x0000000000000400L, 0x0000000000000800L, 043 0x0000000000001000L, 0x0000000000002000L, 0x0000000000004000L, 044 0x0000000000008000L, 0x0000000000010000L, 0x0000000000020000L, 045 0x0000000000040000L, 0x0000000000080000L, 0x0000000000100000L, 046 0x0000000000200000L, 0x0000000000400000L, 0x0000000000800000L, 047 0x0000000001000000L, 0x0000000002000000L, 0x0000000004000000L, 048 0x0000000008000000L, 0x0000000010000000L, 0x0000000020000000L, 049 0x0000000040000000L, 0x0000000080000000L, 0x0000000100000000L, 050 0x0000000200000000L, 0x0000000400000000L, 0x0000000800000000L, 051 0x0000001000000000L, 0x0000002000000000L, 0x0000004000000000L, 052 0x0000008000000000L, 0x0000010000000000L, 0x0000020000000000L, 053 0x0000040000000000L, 0x0000080000000000L, 0x0000100000000000L, 054 0x0000200000000000L, 0x0000400000000000L, 0x0000800000000000L, 055 0x0001000000000000L, 0x0002000000000000L, 0x0004000000000000L, 056 0x0008000000000000L, 0x0010000000000000L, 0x0020000000000000L, 057 0x0040000000000000L, 0x0080000000000000L, 0x0100000000000000L, 058 0x0200000000000000L, 0x0400000000000000L, 0x0800000000000000L, 059 0x1000000000000000L, 0x2000000000000000L, 0x4000000000000000L, 060 0x8000000000000000L}; 061 private long bits; 062 private int length; 063 064 /** 065 * @return the length of bits set 066 */ 067 public int length() { 068 return length; 069 } 070 071 /** 072 * @return the long containing the bits 073 */ 074 public long getBits() { 075 return bits; 076 } 077 078 /** 079 * set the boolean value at the index 080 * 081 * @param index 082 * @param flag 083 * @return the old value held at this index 084 */ 085 public boolean set(int index, boolean flag) { 086 length = Math.max(length, index + 1); 087 boolean oldValue = (bits & BIT_VALUES[index]) != 0; 088 if (flag) { 089 bits |= BIT_VALUES[index]; 090 } else if (oldValue) { 091 bits &= ~(BIT_VALUES[index]); 092 } 093 return oldValue; 094 } 095 096 /** 097 * @param index 098 * @return the boolean value at this index 099 */ 100 public boolean get(int index) { 101 return (bits & BIT_VALUES[index]) != 0; 102 } 103 104 /** 105 * reset all the bit values to false 106 */ 107 public void reset() { 108 bits = 0; 109 } 110 111 /** 112 * reset all the bits to the value supplied 113 * 114 * @param bits 115 */ 116 public void reset(long bits) { 117 this.bits = bits; 118 } 119 120 private void writeObject(java.io.ObjectOutputStream out) throws IOException { 121 writeToStream(out); 122 } 123 124 private void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException { 125 readFromStream(in); 126 } 127 128 /** 129 * write the bits to an output stream 130 * 131 * @param dataOut 132 * @throws IOException 133 */ 134 public void writeToStream(DataOutput dataOut) throws IOException { 135 dataOut.writeByte(length); 136 if (length <= BYTE_SIZE) { 137 dataOut.writeByte((byte)bits); 138 } else if (length <= SHORT_SIZE) { 139 dataOut.writeShort((short)bits); 140 } else if (length <= INT_SIZE) { 141 dataOut.writeInt((int)bits); 142 } else { 143 dataOut.writeLong(bits); 144 } 145 } 146 147 /** 148 * read the bits from an input stream 149 * 150 * @param dataIn 151 * @throws IOException 152 */ 153 public void readFromStream(DataInput dataIn) throws IOException { 154 length = dataIn.readByte(); 155 if (length <= BYTE_SIZE) { 156 bits = dataIn.readByte(); 157 } else if (length <= SHORT_SIZE) { 158 bits = dataIn.readShort(); 159 } else if (length <= INT_SIZE) { 160 bits = dataIn.readInt(); 161 } else { 162 bits = dataIn.readLong(); 163 } 164 } 165}