ActiveMQ example source code file (IndexRootContainer.java)

This example ActiveMQ source code file (IndexRootContainer.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

containerid, containerid, datamanager, indexitem, indexitem, indexmanager, indexrootcontainer, io, ioexception, ioexception, linkedlist, logger, storeentry, storeentry, storelocation, threading, threads, util

The ActiveMQ IndexRootContainer.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.kaha.impl;

import java.io.IOException;
import java.util.LinkedList;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.activemq.kaha.ContainerId;
import org.apache.activemq.kaha.Marshaller;
import org.apache.activemq.kaha.Store;
import org.apache.activemq.kaha.StoreEntry;
import org.apache.activemq.kaha.StoreLocation;
import org.apache.activemq.kaha.impl.data.Item;
import org.apache.activemq.kaha.impl.index.IndexItem;
import org.apache.activemq.kaha.impl.index.IndexManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A container of roots for other Containers
 * 
 * 
 */

class IndexRootContainer {
    
    protected static final Marshaller ROOT_MARSHALLER = Store.OBJECT_MARSHALLER;
    private static final Logger LOG = LoggerFactory.getLogger(IndexRootContainer.class);

    protected IndexItem root;
    protected IndexManager indexManager;
    protected DataManager dataManager;
    protected Map<Object, StoreEntry> map = new ConcurrentHashMap();
    protected LinkedList<StoreEntry> list = new LinkedList();

    IndexRootContainer(IndexItem root, IndexManager im, DataManager dfm) throws IOException {
        this.root = root;
        this.indexManager = im;
        this.dataManager = dfm;
        long nextItem = root.getNextItem();
        while (nextItem != Item.POSITION_NOT_SET) {
            StoreEntry item = indexManager.getIndex(nextItem);
            StoreLocation data = item.getKeyDataItem();
            Object key = dataManager.readItem(ROOT_MARSHALLER, data);
            map.put(key, item);
            list.add(item);
            nextItem = item.getNextItem();
            dataManager.addInterestInFile(item.getKeyFile());
        }
    }

    Set<Object> getKeys() {
        return map.keySet();
    }

    IndexItem addRoot(IndexManager containerIndexManager, ContainerId key) throws IOException {
        if (map.containsKey(key)) {
            removeRoot(containerIndexManager, key);
        }

        StoreLocation data = dataManager.storeDataItem(ROOT_MARSHALLER, key);
        IndexItem newRoot = indexManager.createNewIndex();
        newRoot.setKeyData(data);
        IndexItem containerRoot = containerIndexManager.createNewIndex();
        containerIndexManager.storeIndex(containerRoot);
        newRoot.setValueOffset(containerRoot.getOffset());

        IndexItem last = list.isEmpty() ? null : (IndexItem)list.getLast();
        last = last == null ? root : last;
        long prev = last.getOffset();
        newRoot.setPreviousItem(prev);
        indexManager.storeIndex(newRoot);
        last.setNextItem(newRoot.getOffset());
        indexManager.storeIndex(last);
        map.put(key, newRoot);
        list.add(newRoot);
        return containerRoot;
    }

    void removeRoot(IndexManager containerIndexManager, ContainerId key) throws IOException {
        StoreEntry oldRoot = map.remove(key);
        if (oldRoot != null) {
            dataManager.removeInterestInFile(oldRoot.getKeyFile());
            // get the container root
            IndexItem containerRoot = containerIndexManager.getIndex(oldRoot.getValueOffset());
            if (containerRoot != null) {
                containerIndexManager.freeIndex(containerRoot);
            }
            int index = list.indexOf(oldRoot);
            IndexItem prev = index > 0 ? (IndexItem)list.get(index - 1) : root;
            prev = prev == null ? root : prev;
            IndexItem next = index < (list.size() - 1) ? (IndexItem)list.get(index + 1) : null;
            if (next != null) {
                prev.setNextItem(next.getOffset());
                next.setPreviousItem(prev.getOffset());
                indexManager.updateIndexes(next);
            } else {
                prev.setNextItem(Item.POSITION_NOT_SET);
            }
            indexManager.updateIndexes(prev);
            list.remove(oldRoot);
            indexManager.freeIndex((IndexItem)oldRoot);
        }
    }

    IndexItem getRoot(IndexManager containerIndexManager, ContainerId key) throws IOException {
        StoreEntry index = map.get(key);
        if (index != null) {
            return containerIndexManager.getIndex(index.getValueOffset());
        }
        return null;
    }

    boolean doesRootExist(Object key) {
        return map.containsKey(key);
    }

}