org.apache.activemq.util.BitArrayBin Maven / Gradle / Ivy
/**
* 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.Serializable;
import java.util.LinkedList;
/**
* Holder for many bitArrays - used for message audit
*
*
*/
public class BitArrayBin implements Serializable {
private static final long serialVersionUID = 1L;
private final LinkedList list;
private int maxNumberOfArrays;
private int firstIndex = -1; // leave 'int' for old serialization compatibility and introduce new 'long' field
private long lastInOrderBit=-1;
private long longFirstIndex=-1;
/**
* Create a BitArrayBin to a certain window size (number of messages to
* keep)
*
* @param windowSize
*/
public BitArrayBin(int windowSize) {
maxNumberOfArrays = ((windowSize + 1) / BitArray.LONG_SIZE) + 1;
maxNumberOfArrays = Math.max(maxNumberOfArrays, 1);
list = new LinkedList();
for (int i = 0; i < maxNumberOfArrays; i++) {
list.add(null);
}
}
/**
* Set a bit
*
* @param index
* @param value
* @return true if set
*/
public boolean setBit(long index, boolean value) {
boolean answer = false;
BitArray ba = getBitArray(index);
if (ba != null) {
int offset = getOffset(index);
if (offset >= 0) {
answer = ba.set(offset, value);
}
}
return answer;
}
/**
* Test if in order
* @param index
* @return true if next message is in order
*/
public boolean isInOrder(long index) {
boolean result = false;
if (lastInOrderBit == -1) {
result = true;
} else {
result = lastInOrderBit + 1 == index;
}
lastInOrderBit = index;
return result;
}
/**
* Get the boolean value at the index
*
* @param index
* @return true/false
*/
public boolean getBit(long index) {
boolean answer = index >= longFirstIndex;
BitArray ba = getBitArray(index);
if (ba != null) {
int offset = getOffset(index);
if (offset >= 0) {
answer = ba.get(offset);
return answer;
}
} else {
// gone passed range for previous bins so assume set
answer = true;
}
return answer;
}
/**
* Get the BitArray for the index
*
* @param index
* @return BitArray
*/
private BitArray getBitArray(long index) {
int bin = getBin(index);
BitArray answer = null;
if (bin >= 0) {
if (bin >= maxNumberOfArrays) {
int overShoot = bin - maxNumberOfArrays + 1;
while (overShoot > 0) {
list.removeFirst();
longFirstIndex += BitArray.LONG_SIZE;
list.add(new BitArray());
overShoot--;
}
bin = maxNumberOfArrays - 1;
}
answer = list.get(bin);
if (answer == null) {
answer = new BitArray();
list.set(bin, answer);
}
}
return answer;
}
/**
* Get the index of the bin from the total index
*
* @param index
* @return the index of the bin
*/
private int getBin(long index) {
int answer = 0;
if (longFirstIndex < 0) {
longFirstIndex = (index - (index % BitArray.LONG_SIZE));
} else if (longFirstIndex >= 0) {
answer = (int)((index - longFirstIndex) / BitArray.LONG_SIZE);
}
return answer;
}
/**
* Get the offset into a bin from the total index
*
* @param index
* @return the relative offset into a bin
*/
private int getOffset(long index) {
int answer = 0;
if (longFirstIndex >= 0) {
answer = (int)((index - longFirstIndex) - (BitArray.LONG_SIZE * getBin(index)));
}
return answer;
}
public long getLastSetIndex() {
long result = -1;
if (longFirstIndex >=0) {
result = longFirstIndex;
BitArray last = null;
for (int lastBitArrayIndex = maxNumberOfArrays -1; lastBitArrayIndex >= 0; lastBitArrayIndex--) {
last = list.get(lastBitArrayIndex);
if (last != null) {
result += last.length() -1;
result += lastBitArrayIndex * BitArray.LONG_SIZE;
break;
}
}
}
return result;
}
}