org.sdw.mapping.RMLmapper.java Source code

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Here is the source code for org.sdw.mapping.RMLmapper.java

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/*******************************************************************************
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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.sdw.mapping;

import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.apache.commons.configuration2.Configuration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Ritesh Kumar Singh
 *
 */
public class RMLmapper implements RDFmapper {
    public static final Logger LOG = LoggerFactory.getLogger(RMLmapper.class);
    private static String commonRdfFormat;

    /**
     * Parametrized constructor with single input
     * @param cfg : Configuration file for the dataset
     */
    public RMLmapper(String commonRdfFormat) {
        this.commonRdfFormat = commonRdfFormat;
    }

    /**
     * Calls the interface's execute method with params set
     * @param config : Config of the dataset
     */
    public void parallelExecutor(Configuration config, int numThreads) {
        ExecutorService executor = Executors.newCachedThreadPool();
        for (int i = 0; i < numThreads; i++) {
            executor.execute(new Runnable() {
                @Override
                public void run() {
                    execute(config.getString("sourceFile"), config.getString("mappingFile"),
                            config.getString("outputFile"));
                }
            });
        }
    }

    /**
     * Implemented from the interface
     * @param sourceFile : path to source file
     * @param mappingFile : rml mapping file
     * @param outputFile : file to create after conversion
     */
    public void execute(String sourceFile, String mappingFile, String outputFile) {
        deleteOutputIfExists(outputFile);
        String rmlHome = System.getenv("RML_HOME");
        String baseDir = System.getProperty("user.dir");
        rmlHome = baseDir + "/lib/";
        String command = "java -jar " + rmlHome + "RML-Mapper.jar -m " + mappingFile + " -o " + outputFile + " -f "
                + commonRdfFormat;
        String res[] = executeCommandShell(command);
        if (Integer.parseInt(res[0]) != 0) {
            LOG.error("ERROR : Could not convert the file to rdf format");
        } else {
            LOG.info(res[1]);
        }

    }

    /**
     * Execute command on local shell
     * @param command : Command to be executed
     * @return : A string array with exit code and output of execution
     */
    private String[] executeCommandShell(String command) {
        LOG.info("Shell command: $" + command);
        StringBuffer op = new StringBuffer();
        String out[] = new String[2];
        Process process;
        try {
            process = Runtime.getRuntime().exec(command);
            process.waitFor();
            int exitStatus = process.exitValue();
            out[0] = Integer.toString(exitStatus);
            BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
            String line = null;
            while ((line = reader.readLine()) != null) {
                op.append(line + "\n");
            }
            out[1] = op.toString();
        } catch (Exception e) {
            LOG.error(e.getMessage(), e);
        }

        return out;
    }

    /**
     * Deletes the output file if it already exists
     * @param outputFile : delete this file if already exists
     */
    public void deleteOutputIfExists(String outputFile) {
        LOG.info("Deleting old output file to replace with new one");
        File file = new File(outputFile);
        if (file.exists()) {
            String command = "rm " + outputFile;
            String res[] = executeCommandShell(command);
            if (Integer.parseInt(res[0]) != 0) {
                LOG.error("ERROR: Could not delete file: " + outputFile);
            }
        }
    }
}