net.wastl.rdfdot.render.GraphvizSerializerCommand.java Source code

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Here is the source code for net.wastl.rdfdot.render.GraphvizSerializerCommand.java

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/*
 * Copyright 2014 Sebastian Schaffert (wastl@wastl.net)
 *
 * 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 net.wastl.rdfdot.render;

import net.wastl.rdfdot.config.GraphConfiguration;
import net.wastl.rdfdot.base.GraphvizSerializerString;
import org.apache.commons.io.FileUtils;
import org.apache.commons.lang3.RandomStringUtils;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.*;

/**
 * Add file description here!
 *
 * @author Sebastian Schaffert (sschaffert@apache.org)
 */
public class GraphvizSerializerCommand extends GraphvizSerializerString {

    private static Logger log = LoggerFactory.getLogger(GraphvizSerializerCommand.class);

    private String filename;

    public GraphvizSerializerCommand(GraphConfiguration configuration) {
        super(configuration);
        this.filename = FileUtils.getTempDirectoryPath() + File.separator + RandomStringUtils.randomAlphabetic(8)
                + ".png";
    }

    public GraphvizSerializerCommand(GraphConfiguration configuration, String filename) {
        super(configuration);
        this.filename = filename;
    }

    @Override
    protected void finishSerialization() {
        render(getString(), filename);
    }

    private void render(String data, String filename) {
        log.info("rendering graph using external 'dot' command ...");

        long start = System.currentTimeMillis();

        Process p;
        try {
            p = Runtime.getRuntime().exec(String.format("dot -Tpng -o%s", filename));

            try (PrintWriter out = new PrintWriter(new OutputStreamWriter(p.getOutputStream()))) {
                out.print(data);
            }

            p.waitFor();

            log.info("finished ({}ms)!", System.currentTimeMillis() - start);
        } catch (IOException e) {
            log.error("could not execute dot command: {}", e.getMessage());
        } catch (InterruptedException e) {
            log.error("command execution interrupted");
        }

    }

    /**
     * Return the result image as byte array
     */
    @Override
    public byte[] getResult() {
        try {
            return FileUtils.readFileToByteArray(new File(filename));
        } catch (IOException e) {
            return null;
        }
    }
}