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Camel JCIFS (SMB) component
There is a newer version: 2.25.2
/**************************************************************************************
 https://camel-extra.github.io

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public License
 as published by the Free Software Foundation; either version 3
 of the License, or (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Lesser General Public License for more details.


 You should have received a copy of the GNU Lesser General Public
 License along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 02110-1301, USA.

 http://www.gnu.org/licenses/lgpl-3.0-standalone.html
 ***************************************************************************************/
package org.apacheextras.camel.component.jcifs.strategy;

import java.util.Date;
import java.util.List;

import jcifs.smb.SmbFile;
import org.apache.camel.Exchange;
import org.apache.camel.LoggingLevel;
import org.apache.camel.component.file.GenericFile;
import org.apache.camel.component.file.GenericFileEndpoint;
import org.apache.camel.component.file.GenericFileExclusiveReadLockStrategy;
import org.apache.camel.component.file.GenericFileOperations;
import org.apache.camel.util.CamelLogger;
import org.apache.camel.util.StopWatch;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @see org.apache.camel.component.file.remote.strategy.SftpChangedExclusiveReadLockStrategy
 */
public class SmbChangedExclusiveReadLockStrategy implements GenericFileExclusiveReadLockStrategy {
    private static final Logger LOG = LoggerFactory.getLogger(SmbChangedExclusiveReadLockStrategy.class);
    private long timeout;
    private long checkInterval = 5000;
    private LoggingLevel readLockLoggingLevel = LoggingLevel.WARN;
    private long minLength = 1;
    private long minAge;

    @Override
    public void prepareOnStartup(GenericFileOperations tGenericFileOperations, GenericFileEndpoint tGenericFileEndpoint) throws Exception {
        // noop
    }

    public boolean acquireExclusiveReadLock(GenericFileOperations operations, GenericFile file, Exchange exchange) throws Exception {
        boolean exclusive = false;

        LOG.trace("Waiting for exclusive read lock to file: " + file);

        long lastModified = Long.MIN_VALUE;
        long length = Long.MIN_VALUE;
        StopWatch watch = new StopWatch();
        long startTime = (new Date()).getTime();

        while (!exclusive) {
            // timeout check
            if (timeout > 0) {
                long delta = watch.taken();
                if (delta > timeout) {
                    CamelLogger.log(LOG, readLockLoggingLevel,
                            "Cannot acquire read lock within " + timeout + " millis. Will skip the file: " + file);
                    // we could not get the lock within the timeout period, so return false
                    return false;
                }
            }

            long newLastModified = 0;
            long newLength = 0;

            LOG.trace("Using full directory listing to update file information for {}.", file);
            // fast option not available (smb listFiles only handles directories), so list the directory and filter the file name
            List files = operations.listFiles(file.getParent());

            LOG.trace("List files {} found {} files", file.getAbsoluteFilePath(), files.size());
            for (SmbFile f : files) {
                // use same attribute sources as org.apacheextras.camel.component.jcifs.SmbConsumer#asGenericFile()
                if (f.getName().equals(file.getFileNameOnly())) {
                    newLastModified = f.getLastModified();
                    newLength = f.getContentLength();
                }
            }

            LOG.trace("Previous last modified: " + lastModified + ", new last modified: " + newLastModified);
            LOG.trace("Previous length: " + length + ", new length: " + newLength);
            long newOlderThan = startTime + watch.taken() - minAge;
            LOG.trace("New older than threshold: {}", newOlderThan);

            if (newLength >= minLength && ((minAge == 0 && newLastModified == lastModified && newLength == length) || (minAge != 0 && newLastModified < newOlderThan))) {
                LOG.trace("Read lock acquired.");
                exclusive = true;
            } else {
                // set new base file change information
                lastModified = newLastModified;
                length = newLength;

                boolean interrupted = sleep();
                if (interrupted) {
                    // we were interrupted while sleeping, we are likely being shutdown so return false
                    return false;
                }
            }
        }

        return exclusive;
    }

    private boolean sleep() {
        LOG.trace("Exclusive read lock not granted. Sleeping for " + checkInterval + " millis.");
        try {
            Thread.sleep(checkInterval);
            return false;
        } catch (InterruptedException e) {
            LOG.debug("Sleep interrupted while waiting for exclusive read lock, so breaking out");
            return true;
        }
    }

    @Override
    public void releaseExclusiveReadLockOnAbort(GenericFileOperations operations, GenericFile file, Exchange exchange) throws Exception {
        // noop
    }

    @Override
    public void releaseExclusiveReadLockOnRollback(GenericFileOperations operations, GenericFile file, Exchange exchange) throws Exception {
        // noop
    }

    @Override
    public void releaseExclusiveReadLockOnCommit(GenericFileOperations operations, GenericFile file, Exchange exchange) throws Exception {
        // noop
    }

    public long getTimeout() {
        return timeout;
    }

    @Override
    public void setTimeout(long timeout) {
        this.timeout = timeout;
    }

    public long getCheckInterval() {
        return checkInterval;
    }

    @Override
    public void setCheckInterval(long checkInterval) {
        this.checkInterval = checkInterval;
    }

    @Override
    public void setReadLockLoggingLevel(LoggingLevel readLockLoggingLevel) {
        this.readLockLoggingLevel = readLockLoggingLevel;
    }

    public long getMinLength() {
        return minLength;
    }

    public void setMinLength(long minLength) {
        this.minLength = minLength;
    }

    public long getMinAge() {
        return minAge;
    }

    public void setMinAge(long minAge) {
        this.minAge = minAge;
    }

    @Override
    public void setMarkerFiler(boolean markerFiler) {
        // noop - not supported by smb
    }

    @Override
    public void setDeleteOrphanLockFiles(boolean deleteOrphanLockFiles) {
        // noop - not supported by smb
    }
}