Example usage for java.util.concurrent ExecutorCompletionService take

Introduction

In this page you can find the example usage for java.util.concurrent ExecutorCompletionService take.

Prototype

public Future<V> take() throws InterruptedException

Source Link

Usage

From source file:org.geoserver.bkprst.RestoreTask.java

@Override
public void run() {

    // If previous' backup info cannot be read, aborts the restore
    // Writes info about backup in a file
    BackupTask backupInfo = this.readBackupInfo(this.path);
    if (backupInfo == null) {
        LOGGER.severe("Backup data info were not written properly, the restore will not start");
        this.state = BrTaskState.FAILED;
        return;/*from www . j  ava  2s.co  m*/
    }

    // Sets up the filter to exclude some directories according to the previous backup info
    IOFileFilter excludeFilter = this.getExcludeFilter(backupInfo.includeData, backupInfo.includeGwc,
            backupInfo.includeLog);

    // Sets up source and destination
    File srcMount = new File(this.path);
    File trgMount = this.dataRoot.root();

    // Sets transaction
    this.trans = new RestoreTransaction(this, srcMount, trgMount, excludeFilter);

    try {
        // Start transanction
        this.trans.start();
        if (checkForHalt()) {
            return;
        }

        // Sets up the copy task
        ExecutorService ex = Executors.newFixedThreadPool(2);
        if (ex == null || ex.isTerminated()) {
            throw new IllegalArgumentException(
                    "Unable to run asynchronously using a terminated or null ThreadPoolExecutor");
        }
        ExecutorCompletionService<File> cs = new ExecutorCompletionService<File>(ex);

        this.act = new CopyTree(excludeFilter, cs, srcMount, trgMount);
        this.act.addCopyListener(new DefaultProgress(this.id.toString()) {
            public void onUpdateProgress(float percent) {
                super.onUpdateProgress(percent);
                progress = percent;
            }
        });

        // Starts restore
        int workSize = this.act.copy();
        LOGGER.info("Restore " + this.id + " has started");
        this.startTime = new Date();
        this.state = BrTaskState.RUNNING;

        // This is to keep track af restore advancement
        while (workSize-- > 0) {
            Future<File> future = cs.take();
            try {
                LOGGER.info("copied file: " + future.get());
            } catch (ExecutionException e) {

                LOGGER.log(Level.INFO, e.getLocalizedMessage(), e);
            }
            if (checkForHalt()) {
                ex.shutdown();
                if (!ex.awaitTermination(5, TimeUnit.SECONDS)) {
                    throw new RuntimeException("Unable to stop backup task");
                }
                return;
            }
        }

        // Restore completed
        this.trans.commit();

        // reload the config from disk
        getGeoServer().reload();
    } catch (Exception e) {
        LOGGER.log(Level.SEVERE, e.getLocalizedMessage(), e);

        // In case of errors, rollback
        this.trans.rollback();
    } finally {
        haltSemaphore.release();
    }
}