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ActiveMQ example source code file (HashPage.java)

This example ActiveMQ source code file (HashPage.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

arraylist, datainput, dataoutput, hashentry, hashentry, hashpage, hashpage, io, ioexception, ioexception, list, list, logger, string, stringbuffer, util

The ActiveMQ HashPage.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.index.hash;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.activemq.kaha.Marshaller;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A Page within a HashPage
 * 
 * 
 */
class HashPage {
    static final int PAGE_HEADER_SIZE = 17;
    private static final transient Logger LOG = LoggerFactory.getLogger(HashPage.class);

    private int maximumEntries;
    private long id;
    private int binId;
    private List<HashEntry> hashIndexEntries;
    private int persistedSize;
    /*
     * for persistence only
     */
    private long nextFreePageId = HashEntry.NOT_SET;
    private boolean active = true;

    
    /**
     * Constructor
     * 
     * @param maximumEntries
     */
    public HashPage(int maximumEntries) {
        this.maximumEntries = maximumEntries;
        this.hashIndexEntries = new ArrayList<HashEntry>(maximumEntries);
    }

    public String toString() {
        return "HashPage[" + getId() + ":" + binId + ":" + id+"] size = " + persistedSize;
    }

    public boolean equals(Object o) {
        boolean result = false;
        if (o instanceof HashPage) {
            HashPage other = (HashPage)o;
            result = other.id == id;
        }
        return result;
    }

    public int hashCode() {
        return (int)id;
    }

    boolean isActive() {
        return this.active;
    }

    void setActive(boolean active) {
        this.active = active;
    }

    
    long getId() {
        return id;
    }

    void setId(long id) {
        this.id = id;
    }

    int getPersistedSize() {
        return persistedSize;
    }

    void write(Marshaller keyMarshaller, DataOutput dataOut) throws IOException {
        persistedSize=hashIndexEntries.size();
        writeHeader(dataOut);
        dataOut.writeInt(persistedSize);
        for (HashEntry entry : hashIndexEntries) {
            entry.write(keyMarshaller, dataOut);
        }
    }

    void read(Marshaller keyMarshaller, DataInput dataIn) throws IOException {
        readHeader(dataIn);
        dataIn.readInt();
        int size = persistedSize;
        hashIndexEntries.clear();
        for (int i = 0; i < size; i++) {
            HashEntry entry = new HashEntry();
            entry.read(keyMarshaller, dataIn);
            hashIndexEntries.add(entry);
        }
    }

    void readHeader(DataInput dataIn) throws IOException {
        active = dataIn.readBoolean();
        nextFreePageId = dataIn.readLong();
        binId = dataIn.readInt();
        persistedSize = dataIn.readInt();
    }

    void writeHeader(DataOutput dataOut) throws IOException {
        dataOut.writeBoolean(isActive());
        dataOut.writeLong(nextFreePageId);
        dataOut.writeInt(binId);
        persistedSize=hashIndexEntries.size();
        dataOut.writeInt(persistedSize);
    }
    

    boolean isEmpty() {
        return hashIndexEntries.isEmpty();
    }

    boolean isFull() {
        return hashIndexEntries.size() >= maximumEntries;
    }

    boolean isUnderflowed() {
        return hashIndexEntries.size() < (maximumEntries / 2);
    }

    boolean isOverflowed() {
        return hashIndexEntries.size() > maximumEntries;
    }

    List<HashEntry> getEntries() {
        return hashIndexEntries;
    }

    void setEntries(List<HashEntry> newEntries) {
        this.hashIndexEntries = newEntries;
    }

    int getMaximumEntries() {
        return this.maximumEntries;
    }

    void setMaximumEntries(int maximumEntries) {
        this.maximumEntries = maximumEntries;
    }

    int size() {
        return hashIndexEntries.size();
    }

    void reset() throws IOException {
        hashIndexEntries.clear();
        persistedSize=0;
    }

    void addHashEntry(int index, HashEntry entry) throws IOException {
        hashIndexEntries.add(index, entry);
    }

    HashEntry getHashEntry(int index) {
        HashEntry result = hashIndexEntries.get(index);
        return result;
    }

    HashEntry removeHashEntry(int index) throws IOException {
        HashEntry result = hashIndexEntries.remove(index);
        return result;
    }

    void removeAllTreeEntries(List<HashEntry> c) {
        hashIndexEntries.removeAll(c);
    }

    List<HashEntry> getSubList(int from, int to) {
        return new ArrayList<HashEntry>(hashIndexEntries.subList(from, to));
    }

    /**
     * @return the binId
     */
    int getBinId() {
        return this.binId;
    }

    /**
     * @param binId the binId to set
     */
    void setBinId(int binId) {
        this.binId = binId;
    }

    String dump() {

        StringBuffer str = new StringBuffer(32);
        str.append(toString());
        str.append(": ");
        for (HashEntry entry : hashIndexEntries) {
            str.append(entry);
            str.append(",");
        }
        return str.toString();
    }
}

Other ActiveMQ examples (source code examples)

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