com.datatorrent.stram.util.FSJsonLineFile.java Source code

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Here is the source code for com.datatorrent.stram.util.FSJsonLineFile.java

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/**
 * Copyright (C) 2015 DataTorrent, Inc.
 *
 * 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 com.datatorrent.stram.util;

import java.io.Closeable;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.*;
import org.apache.hadoop.fs.permission.FsPermission;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jettison.json.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * <p>FSJsonLineFile class.</p>
 *
 * @since 1.0.2
 */
public class FSJsonLineFile implements Closeable {
    private final FileSystem fs;
    private final ObjectMapper objectMapper;
    private final FSDataOutputStream os;
    private static final Logger LOG = LoggerFactory.getLogger(FSJsonLineFile.class);

    public FSJsonLineFile(Path path, FsPermission permission) throws IOException {
        fs = FileSystem.newInstance(path.toUri(), new Configuration());
        FSDataOutputStream myos;
        if (fs.exists(path)) {
            try {
                // happens if not the first application attempt
                myos = fs.append(path);
            } catch (IOException ex) {
                LOG.warn("Caught exception (OK during unit test): {}", ex.getMessage());
                myos = FileSystem.create(fs, path, permission);
            }
        } else {
            myos = FileSystem.create(fs, path, permission);
        }
        os = myos;
        this.objectMapper = (new JSONSerializationProvider()).getContext(null);
    }

    public synchronized void append(JSONObject json) throws IOException {
        os.writeBytes(json.toString() + "\n");
        os.hflush();
    }

    public synchronized void append(Object obj) throws IOException {
        os.writeBytes(objectMapper.writeValueAsString(obj) + "\n");
        os.hflush();
    }

    @Override
    public void close() throws IOException {
        os.close();
        fs.close();
    }

}