/**
* 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.broker.region.cursors;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.apache.activemq.broker.region.MessageReference;
import org.apache.activemq.command.MessageId;
import org.apache.activemq.management.SizeStatisticImpl;
public class OrderedPendingList implements PendingList {
private PendingNode root = null;
private PendingNode tail = null;
private final Map<MessageId, PendingNode> map = new HashMap<MessageId, PendingNode>();
private final SizeStatisticImpl messageSize;
private final PendingMessageHelper pendingMessageHelper;
public OrderedPendingList() {
messageSize = new SizeStatisticImpl("messageSize", "The size in bytes of the pending messages");
messageSize.setEnabled(true);
pendingMessageHelper = new PendingMessageHelper(map, messageSize);
}
@Override
public PendingNode addMessageFirst(MessageReference message) {
PendingNode node = new PendingNode(this, message);
if (root == null) {
root = node;
tail = node;
} else {
root.linkBefore(node);
root = node;
}
pendingMessageHelper.addToMap(message, node);
return node;
}
@Override
public PendingNode addMessageLast(MessageReference message) {
PendingNode node = new PendingNode(this, message);
if (root == null) {
root = node;
} else {
tail.linkAfter(node);
}
tail = node;
pendingMessageHelper.addToMap(message, node);
return node;
}
@Override
public void clear() {
this.root = null;
this.tail = null;
this.map.clear();
this.messageSize.reset();
}
@Override
public boolean isEmpty() {
return this.map.isEmpty();
}
@Override
public Iterator<MessageReference> iterator() {
return new Iterator<MessageReference>() {
private PendingNode current = null;
private PendingNode next = root;
@Override
public boolean hasNext() {
return next != null;
}
@Override
public MessageReference next() {
MessageReference result = null;
this.current = this.next;
result = this.current.getMessage();
this.next = (PendingNode) this.next.getNext();
return result;
}
@Override
public void remove() {
if (this.current != null && this.current.getMessage() != null) {
pendingMessageHelper.removeFromMap(this.current.getMessage());
}
removeNode(this.current);
}
};
}
@Override
public PendingNode remove(MessageReference message) {
PendingNode node = null;
if (message != null) {
node = pendingMessageHelper.removeFromMap(message);
removeNode(node);
}
return node;
}
@Override
public int size() {
return this.map.size();
}
@Override
public long messageSize() {
return this.messageSize.getTotalSize();
}
void removeNode(PendingNode node) {
if (node != null) {
pendingMessageHelper.removeFromMap(node.getMessage());
if (root == node) {
root = (PendingNode) node.getNext();
}
if (tail == node) {
tail = (PendingNode) node.getPrevious();
}
node.unlink();
}
}
List<PendingNode> getAsList() {
List<PendingNode> result = new ArrayList<PendingNode>(size());
PendingNode node = root;
while (node != null) {
result.add(node);
node = (PendingNode) node.getNext();
}
return result;
}
@Override
public String toString() {
return "OrderedPendingList(" + System.identityHashCode(this) + ")";
}
@Override
public boolean contains(MessageReference message) {
if (message != null) {
return this.map.containsKey(message.getMessageId());
}
return false;
}
@Override
public Collection<MessageReference> values() {
return getValues(this);
}
public static Collection<MessageReference> getValues(final PendingList pendingList) {
List<MessageReference> messageReferences = new ArrayList<MessageReference>();
Iterator<MessageReference> iterator = pendingList.iterator();
while (iterator.hasNext()) {
messageReferences.add(iterator.next());
}
return messageReferences;
}
@Override
public void addAll(PendingList pendingList) {
if (pendingList != null) {
for(MessageReference messageReference : pendingList) {
addMessageLast(messageReference);
}
}
}
@Override
public MessageReference get(MessageId messageId) {
PendingNode node = map.get(messageId);
if (node != null) {
return node.getMessage();
}
return null;
}
public void insertAtHead(List<MessageReference> list) {
if (list != null && !list.isEmpty()) {
PendingNode newHead = null;
PendingNode appendNode = null;
for (MessageReference ref : list) {
PendingNode node = new PendingNode(this, ref);
pendingMessageHelper.addToMap(ref, node);
if (newHead == null) {
newHead = node;
appendNode = node;
continue;
}
appendNode.linkAfter(node);
appendNode = node;
}
// insert this new list at root
if (root == null) {
root = newHead;
tail = appendNode;
} else {
appendNode.linkAfter(root);
root = newHead;
}
}
}
}