FileServerConnectorCallback.java

/*
 * Copyright (c) 2017, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 * WSO2 Inc. 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.wso2.carbon.transport.file.connector.server;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.wso2.carbon.messaging.CarbonCallback;
import org.wso2.carbon.messaging.CarbonMessage;
import org.wso2.carbon.transport.file.connector.server.exception.FileServerConnectorException;
import org.wso2.carbon.transport.file.connector.server.util.FileTransportUtils;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

/**
 * This {@link CarbonCallback} will be called by a message processsor to acknowledge that
 * it has finished processing the file input stream, so it may be closed from the transport end.
 */
public class FileServerConnectorCallback implements CarbonCallback {

    private static final Logger log = LoggerFactory.getLogger(FileServerConnectorCallback.class);
    /**
     * Countdown latch to wait for the acknowledgement from the application layer.
     */
    private CountDownLatch latch = new CountDownLatch(1);

    @Override
    public void done(CarbonMessage carbonMessage) {
        if (log.isDebugEnabled()) {
            log.debug("Message processor acknowledgement received.");
        }
        latch.countDown();
    }

    /**
     * This makes the relevant process to wait till there is a acknowledgement from the application layer.
     *
     * @param timeOutInterval Time-out interval in milliseconds for waiting for the acknowledgement
     * @param deleteIfNotAck  If the message processor did not acknowledge, whether to delete the file or not.
     * @param fileURI         The URI of the file which is being processed.
     * @throws InterruptedException If this thread was interrupted while waiting for the acknowledgement.
     * @throws FileServerConnectorException If deleteIfNotAcknowledged parameter is set to false,
     *  and acknowledgement was not received.
     */
    protected void waitTillDone(long timeOutInterval, boolean deleteIfNotAck, String fileURI)
            throws InterruptedException, FileServerConnectorException {
        boolean isCallbackReceived = latch.await(timeOutInterval, TimeUnit.MILLISECONDS);

        if (!isCallbackReceived) {
            if (deleteIfNotAck) {
                log.warn("The time for waiting for the acknowledgement exceeded " + timeOutInterval + "ms. Proceeding "
                        + "to deleting the file: " + FileTransportUtils.maskURLPassword(fileURI));
            } else {
                throw new FileServerConnectorException("Message processor did not acknowledge. " +
                        "Wait timed out  after  " + timeOutInterval + "ms. Aborting processing of file: " +
                        FileTransportUtils.maskURLPassword(fileURI));
            }
        }
    }
}