ActiveMQ example source code file (JobSchedulerStore.java)

This example ActiveMQ source code file (JobSchedulerStore.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

btreeindex, btreeindex, exception, file, integer, io, ioexception, ioexception, joblocation, jobschedulerimpl, jobschedulerimpl, jobschedulerstore, metadata, metadata, metadatamarshaller, util

The ActiveMQ JobSchedulerStore.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.broker.scheduler;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;
import org.apache.activemq.util.IOHelper;
import org.apache.activemq.util.ServiceStopper;
import org.apache.activemq.util.ServiceSupport;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.kahadb.index.BTreeIndex;
import org.apache.kahadb.journal.Journal;
import org.apache.kahadb.journal.Location;
import org.apache.kahadb.page.Page;
import org.apache.kahadb.page.PageFile;
import org.apache.kahadb.page.Transaction;
import org.apache.kahadb.util.ByteSequence;
import org.apache.kahadb.util.IntegerMarshaller;
import org.apache.kahadb.util.LockFile;
import org.apache.kahadb.util.StringMarshaller;
import org.apache.kahadb.util.VariableMarshaller;

public class JobSchedulerStore extends ServiceSupport {
    static final Logger LOG = LoggerFactory.getLogger(JobSchedulerStore.class);
    private static final int DATABASE_LOCKED_WAIT_DELAY = 10 * 1000;

    public static final int CLOSED_STATE = 1;
    public static final int OPEN_STATE = 2;

    private File directory;
    PageFile pageFile;
    private Journal journal;
    private LockFile lockFile;
    private boolean failIfDatabaseIsLocked;
    private int journalMaxFileLength = Journal.DEFAULT_MAX_FILE_LENGTH;
    private int journalMaxWriteBatchSize = Journal.DEFAULT_MAX_WRITE_BATCH_SIZE;
    private boolean enableIndexWriteAsync = false;
    // private int indexWriteBatchSize = PageFile.DEFAULT_WRITE_BATCH_SIZE;
    MetaData metaData = new MetaData(this);
    final MetaDataMarshaller metaDataMarshaller = new MetaDataMarshaller(this);
    Map<String, JobSchedulerImpl> schedulers = new HashMap();

    protected class MetaData {
        protected MetaData(JobSchedulerStore store) {
            this.store = store;
        }
        private final JobSchedulerStore store;
        Page<MetaData> page;
        BTreeIndex<Integer, Integer> journalRC;
        BTreeIndex<String, JobSchedulerImpl> storedSchedulers;

        void createIndexes(Transaction tx) throws IOException {
            this.storedSchedulers = new BTreeIndex<String, JobSchedulerImpl>(pageFile, tx.allocate().getPageId());
            this.journalRC = new BTreeIndex<Integer, Integer>(pageFile, tx.allocate().getPageId());
        }

        void load(Transaction tx) throws IOException {
            this.storedSchedulers.setKeyMarshaller(StringMarshaller.INSTANCE);
            this.storedSchedulers.setValueMarshaller(new JobSchedulerMarshaller(this.store));
            this.storedSchedulers.load(tx);
            this.journalRC.setKeyMarshaller(IntegerMarshaller.INSTANCE);
            this.journalRC.setValueMarshaller(IntegerMarshaller.INSTANCE);
            this.journalRC.load(tx);
        }

        void loadScheduler(Transaction tx, Map<String, JobSchedulerImpl> schedulers) throws IOException {
            for (Iterator<Entry i = this.storedSchedulers.iterator(tx); i.hasNext();) {
                Entry<String, JobSchedulerImpl> entry = i.next();
                entry.getValue().load(tx);
                schedulers.put(entry.getKey(), entry.getValue());
            }
        }

        public void read(DataInput is) throws IOException {
            this.storedSchedulers = new BTreeIndex<String, JobSchedulerImpl>(pageFile, is.readLong());
            this.storedSchedulers.setKeyMarshaller(StringMarshaller.INSTANCE);
            this.storedSchedulers.setValueMarshaller(new JobSchedulerMarshaller(this.store));
            this.journalRC = new BTreeIndex<Integer, Integer>(pageFile, is.readLong());
            this.journalRC.setKeyMarshaller(IntegerMarshaller.INSTANCE);
            this.journalRC.setValueMarshaller(IntegerMarshaller.INSTANCE);
        }

        public void write(DataOutput os) throws IOException {
            os.writeLong(this.storedSchedulers.getPageId());
            os.writeLong(this.journalRC.getPageId());

        }
    }

    class MetaDataMarshaller extends VariableMarshaller<MetaData> {
        private final JobSchedulerStore store;

        MetaDataMarshaller(JobSchedulerStore store) {
            this.store = store;
        }
        public MetaData readPayload(DataInput dataIn) throws IOException {
            MetaData rc = new MetaData(this.store);
            rc.read(dataIn);
            return rc;
        }

        public void writePayload(MetaData object, DataOutput dataOut) throws IOException {
            object.write(dataOut);
        }
    }

    class ValueMarshaller extends VariableMarshaller<List {
        public List<JobLocation> readPayload(DataInput dataIn) throws IOException {
            List<JobLocation> result = new ArrayList();
            int size = dataIn.readInt();
            for (int i = 0; i < size; i++) {
                JobLocation jobLocation = new JobLocation();
                jobLocation.readExternal(dataIn);
                result.add(jobLocation);
            }
            return result;
        }

        public void writePayload(List<JobLocation> value, DataOutput dataOut) throws IOException {
            dataOut.writeInt(value.size());
            for (JobLocation jobLocation : value) {
                jobLocation.writeExternal(dataOut);
            }
        }
    }

    class JobSchedulerMarshaller extends VariableMarshaller<JobSchedulerImpl> {
        private final JobSchedulerStore store;
        JobSchedulerMarshaller(JobSchedulerStore store) {
            this.store = store;
        }
        public JobSchedulerImpl readPayload(DataInput dataIn) throws IOException {
            JobSchedulerImpl result = new JobSchedulerImpl(this.store);
            result.read(dataIn);
            return result;
        }

        public void writePayload(JobSchedulerImpl js, DataOutput dataOut) throws IOException {
            js.write(dataOut);
        }
    }

    public File getDirectory() {
        return directory;
    }

    public void setDirectory(File directory) {
        this.directory = directory;
    }
    
    public long size() {
        if ( !isStarted() ) {
            return 0;
        }
        try {
            return journal.getDiskSize() + pageFile.getDiskSize();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public JobScheduler getJobScheduler(final String name) throws Exception {
        JobSchedulerImpl result = this.schedulers.get(name);
        if (result == null) {
            final JobSchedulerImpl js = new JobSchedulerImpl(this);
            js.setName(name);
            getPageFile().tx().execute(new Transaction.Closure<IOException>() {
                public void execute(Transaction tx) throws IOException {
                    js.createIndexes(tx);
                    js.load(tx);
                    metaData.storedSchedulers.put(tx, name, js);
                }
            });
            result = js;
            this.schedulers.put(name, js);
            if (isStarted()) {
                result.start();
            }
            this.pageFile.flush();
        }
        return result;
    }

    synchronized public boolean removeJobScheduler(final String name) throws Exception {
        boolean result = false;
        final JobSchedulerImpl js = this.schedulers.remove(name);
        result = js != null;
        if (result) {
            js.stop();
            getPageFile().tx().execute(new Transaction.Closure<IOException>() {
                public void execute(Transaction tx) throws IOException {
                    metaData.storedSchedulers.remove(tx, name);
                    js.destroy(tx);
                }
            });
        }
        return result;
    }

    @Override
    protected synchronized void doStart() throws Exception {
        if (this.directory == null) {
            this.directory = new File(IOHelper.getDefaultDataDirectory() + File.pathSeparator + "delayedDB");
        }
        IOHelper.mkdirs(this.directory);
        lock();
        this.journal = new Journal();
        this.journal.setDirectory(directory);
        this.journal.setMaxFileLength(getJournalMaxFileLength());
        this.journal.setWriteBatchSize(getJournalMaxWriteBatchSize());
        this.journal.start();
        this.pageFile = new PageFile(directory, "scheduleDB");
        this.pageFile.load();

        this.pageFile.tx().execute(new Transaction.Closure<IOException>() {
            public void execute(Transaction tx) throws IOException {
                if (pageFile.getPageCount() == 0) {
                    Page<MetaData> page = tx.allocate();
                    assert page.getPageId() == 0;
                    page.set(metaData);
                    metaData.page = page;
                    metaData.createIndexes(tx);
                    tx.store(metaData.page, metaDataMarshaller, true);

                } else {
                    Page<MetaData> page = tx.load(0, metaDataMarshaller);
                    metaData = page.get();
                    metaData.page = page;
                }
                metaData.load(tx);
                metaData.loadScheduler(tx, schedulers);
                for (JobSchedulerImpl js :schedulers.values()) {
                    try {
                        js.start();
                    } catch (Exception e) {
                        JobSchedulerStore.LOG.error("Failed to load " + js.getName(),e);
                    }
               }
            }
        });

        this.pageFile.flush();
        LOG.info(this + " started");
    }
    
    @Override
    protected synchronized void doStop(ServiceStopper stopper) throws Exception {
        for (JobSchedulerImpl js : this.schedulers.values()) {
            js.stop();
        }
        if (this.pageFile != null) {
            this.pageFile.unload();
        }
        if (this.journal != null) {
            journal.close();
        }
        if (this.lockFile != null) {
            this.lockFile.unlock();
        }
        this.lockFile = null;
        LOG.info(this + " stopped");

    }

    synchronized void incrementJournalCount(Transaction tx, Location location) throws IOException {
        int logId = location.getDataFileId();
        Integer val = this.metaData.journalRC.get(tx, logId);
        int refCount = val != null ? val.intValue() + 1 : 1;
        this.metaData.journalRC.put(tx, logId, refCount);

    }

    synchronized void decrementJournalCount(Transaction tx, Location location) throws IOException {
        int logId = location.getDataFileId();
        int refCount = this.metaData.journalRC.get(tx, logId);
        refCount--;
        if (refCount <= 0) {
            this.metaData.journalRC.remove(tx, logId);
            Set<Integer> set = new HashSet();
            set.add(logId);
            this.journal.removeDataFiles(set);
        } else {
            this.metaData.journalRC.put(tx, logId, refCount);
        }

    }

    synchronized ByteSequence getPayload(Location location) throws IllegalStateException, IOException {
        ByteSequence result = null;
        result = this.journal.read(location);
        return result;
    }

    synchronized Location write(ByteSequence payload, boolean sync) throws IllegalStateException, IOException {
        return this.journal.write(payload, sync);
    }

    private void lock() throws IOException {
        if (lockFile == null) {
            File lockFileName = new File(directory, "lock");
            lockFile = new LockFile(lockFileName, true);
            if (failIfDatabaseIsLocked) {
                lockFile.lock();
            } else {
                while (true) {
                    try {
                        lockFile.lock();
                        break;
                    } catch (IOException e) {
                        LOG.info("Database " + lockFileName + " is locked... waiting "
                                + (DATABASE_LOCKED_WAIT_DELAY / 1000)
                                + " seconds for the database to be unlocked. Reason: " + e);
                        try {
                            Thread.sleep(DATABASE_LOCKED_WAIT_DELAY);
                        } catch (InterruptedException e1) {
                        }
                    }
                }
            }
        }
    }

    PageFile getPageFile() {
        this.pageFile.isLoaded();
        return this.pageFile;
    }

    public boolean isFailIfDatabaseIsLocked() {
        return failIfDatabaseIsLocked;
    }

    public void setFailIfDatabaseIsLocked(boolean failIfDatabaseIsLocked) {
        this.failIfDatabaseIsLocked = failIfDatabaseIsLocked;
    }

    public int getJournalMaxFileLength() {
        return journalMaxFileLength;
    }

    public void setJournalMaxFileLength(int journalMaxFileLength) {
        this.journalMaxFileLength = journalMaxFileLength;
    }

    public int getJournalMaxWriteBatchSize() {
        return journalMaxWriteBatchSize;
    }

    public void setJournalMaxWriteBatchSize(int journalMaxWriteBatchSize) {
        this.journalMaxWriteBatchSize = journalMaxWriteBatchSize;
    }

    public boolean isEnableIndexWriteAsync() {
        return enableIndexWriteAsync;
    }

    public void setEnableIndexWriteAsync(boolean enableIndexWriteAsync) {
        this.enableIndexWriteAsync = enableIndexWriteAsync;
    }

    @Override
    public String toString() {
        return "JobSchedulerStore:" + this.directory;
    }

}