org.springframework.xd.integration.hadoop.outbound.HdfsPartitionDataStoreMessageHandler.java Source code

Introduction

Here is the source code for org.springframework.xd.integration.hadoop.outbound.HdfsPartitionDataStoreMessageHandler.java

Source

/*
 * Copyright 2014 the original author or authors.
 *
 * Licensed 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.springframework.xd.integration.hadoop.outbound;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.data.hadoop.store.PartitionDataStoreWriter;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHandlingException;
import org.springframework.util.Assert;

/**
 * Spring Integration {@code MessageHandler} handling {@code Message} writing into hdfs using {@code PartitionDataStoreWriter}.
 *
 * @author Janne Valkealahti
 */
public class HdfsPartitionDataStoreMessageHandler extends HdfsStoreMessageHandler {

    private static final Log logger = LogFactory.getLog(HdfsPartitionDataStoreMessageHandler.class);

    private PartitionDataStoreWriter<String, Message<?>> storePartitionWriter;

    /**
     * Instantiates a new hdfs partition data store message handler.
     *
     * @param storePartitionWriter the store partition writer
     */
    public HdfsPartitionDataStoreMessageHandler(PartitionDataStoreWriter<String, Message<?>> storePartitionWriter) {
        Assert.notNull(storePartitionWriter, "Writer must be set");
        this.storePartitionWriter = storePartitionWriter;
    }

    @Override
    protected void onInit() throws Exception {
        super.onInit();
        Assert.notNull(storePartitionWriter, "Data Writer must be set");
    }

    @Override
    protected void doStop() {
        try {
            if (storePartitionWriter != null) {
                storePartitionWriter.close();
                storePartitionWriter = null;
            }
        } catch (Exception e) {
            logger.error("Error closing writer", e);
        }
    };

    @Override
    protected void doWrite(Message<?> message) throws Exception {
        Assert.notNull(storePartitionWriter, "Writer already closed");
        Object payload = message.getPayload();
        if (payload instanceof String) {
            storePartitionWriter.write((String) payload, message);
        } else {
            throw new MessageHandlingException(message, "message not a String");
        }
    }

}