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ActiveMQ example source code file (SequenceSet.java)
The ActiveMQ SequenceSet.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.kahadb.util; import java.io.DataInput; import java.io.DataOutput; import java.io.IOException; import java.util.ArrayList; import java.util.List; import java.util.NoSuchElementException; /** * Keeps track of a added long values. Collapses ranges of numbers using a * Sequence representation. Use to keep track of received message ids to find * out if a message is duplicate or if there are any missing messages. * * @author chirino */ public class SequenceSet extends LinkedNodeList<Sequence> { public static class Marshaller implements org.apache.kahadb.util.Marshaller<SequenceSet> { public static final Marshaller INSTANCE = new Marshaller(); public SequenceSet readPayload(DataInput in) throws IOException { SequenceSet value = new SequenceSet(); int count = in.readInt(); for (int i = 0; i < count; i++) { if( in.readBoolean() ) { Sequence sequence = new Sequence(in.readLong(), in.readLong()); value.addLast(sequence); } else { Sequence sequence = new Sequence(in.readLong()); value.addLast(sequence); } } return value; } public void writePayload(SequenceSet value, DataOutput out) throws IOException { out.writeInt(value.size()); Sequence sequence = value.getHead(); while (sequence != null ) { if( sequence.range() > 1 ) { out.writeBoolean(true); out.writeLong(sequence.first); out.writeLong(sequence.last); } else { out.writeBoolean(false); out.writeLong(sequence.first); } sequence = sequence.getNext(); } } public int getFixedSize() { return -1; } public SequenceSet deepCopy(SequenceSet value) { SequenceSet rc = new SequenceSet(); Sequence sequence = value.getHead(); while (sequence != null ) { rc.add(new Sequence(sequence.first, sequence.last)); sequence = sequence.getNext(); } return rc; } public boolean isDeepCopySupported() { return true; } } public void add(Sequence value) { // TODO we can probably optimize this a bit for(long i=value.first; i<value.last+1; i++) { add(i); } } /** * * @param value * the value to add to the list * @return false if the value was a duplicate. */ public boolean add(long value) { if (isEmpty()) { addFirst(new Sequence(value)); return true; } Sequence sequence = getHead(); while (sequence != null) { if (sequence.isAdjacentToLast(value)) { // grow the sequence... sequence.last = value; // it might connect us to the next sequence.. if (sequence.getNext() != null) { Sequence next = sequence.getNext(); if (next.isAdjacentToFirst(value)) { // Yep the sequence connected.. so join them. sequence.last = next.last; next.unlink(); } } return true; } if (sequence.isAdjacentToFirst(value)) { // grow the sequence... sequence.first = value; // it might connect us to the previous if (sequence.getPrevious() != null) { Sequence prev = sequence.getPrevious(); if (prev.isAdjacentToLast(value)) { // Yep the sequence connected.. so join them. sequence.first = prev.first; prev.unlink(); } } return true; } // Did that value land before this sequence? if (value < sequence.first) { // Then insert a new entry before this sequence item. sequence.linkBefore(new Sequence(value)); return true; } // Did that value land within the sequence? The it's a duplicate. if (sequence.contains(value)) { return false; } sequence = sequence.getNext(); } // Then the value is getting appended to the tail of the sequence. addLast(new Sequence(value)); return true; } /** * Removes and returns the first element from this list. * * @return the first element from this list. * @throws NoSuchElementException if this list is empty. */ public long removeFirst() { if (isEmpty()) { throw new NoSuchElementException(); } Sequence rc = removeFirstSequence(1); return rc.first; } public Sequence removeLastSequence() { if (isEmpty()) { return null; } Sequence rc = getTail(); rc.unlink(); return rc; } /** * Removes and returns the first sequence that is count range large. * * @return a sequence that is count range large, or null if no sequence is that large in the list. */ public Sequence removeFirstSequence(long count) { if (isEmpty()) { return null; } Sequence sequence = getHead(); while (sequence != null ) { if (sequence.range() == count ) { sequence.unlink(); return sequence; } if (sequence.range() > count ) { Sequence rc = new Sequence(sequence.first, sequence.first+count); sequence.first+=count; return rc; } sequence = sequence.getNext(); } return null; } /** * @return all the id Sequences that are missing from this set that are not * in between the range provided. */ public List<Sequence> getMissing(long first, long last) { ArrayList<Sequence> rc = new ArrayList Other ActiveMQ examples (source code examples)Here is a short list of links related to this ActiveMQ SequenceSet.java source code file: |
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