adams.flow.sink.JsonFileWriter.java Source code

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Here is the source code for adams.flow.sink.JsonFileWriter.java

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/*
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * JsonFileWriter.java
 * Copyright (C) 2013-2016 University of Waikato, Hamilton, New Zealand
 */

package adams.flow.sink;

import adams.core.io.PrettyPrintingSupporter;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonElement;
import com.google.gson.JsonParser;
import net.minidev.json.JSONAware;
import adams.core.io.FileUtils;

/**
 <!-- globalinfo-start -->
 * Writes a JSON object&#47;array to a file.
 * <br><br>
 <!-- globalinfo-end -->
 *
 <!-- flow-summary-start -->
 * Input&#47;output:<br>
 * - accepts:<br>
 * &nbsp;&nbsp;&nbsp;net.minidev.json.JSONAware<br>
 * <br><br>
 <!-- flow-summary-end -->
 *
 <!-- options-start -->
 * <pre>-logging-level &lt;OFF|SEVERE|WARNING|INFO|CONFIG|FINE|FINER|FINEST&gt; (property: loggingLevel)
 * &nbsp;&nbsp;&nbsp;The logging level for outputting errors and debugging output.
 * &nbsp;&nbsp;&nbsp;default: WARNING
 * </pre>
 * 
 * <pre>-name &lt;java.lang.String&gt; (property: name)
 * &nbsp;&nbsp;&nbsp;The name of the actor.
 * &nbsp;&nbsp;&nbsp;default: JsonFileWriter
 * </pre>
 * 
 * <pre>-annotation &lt;adams.core.base.BaseAnnotation&gt; (property: annotations)
 * &nbsp;&nbsp;&nbsp;The annotations to attach to this actor.
 * &nbsp;&nbsp;&nbsp;default: 
 * </pre>
 * 
 * <pre>-skip &lt;boolean&gt; (property: skip)
 * &nbsp;&nbsp;&nbsp;If set to true, transformation is skipped and the input token is just forwarded 
 * &nbsp;&nbsp;&nbsp;as it is.
 * &nbsp;&nbsp;&nbsp;default: false
 * </pre>
 * 
 * <pre>-stop-flow-on-error &lt;boolean&gt; (property: stopFlowOnError)
 * &nbsp;&nbsp;&nbsp;If set to true, the flow gets stopped in case this actor encounters an error;
 * &nbsp;&nbsp;&nbsp; useful for critical actors.
 * &nbsp;&nbsp;&nbsp;default: false
 * </pre>
 * 
 * <pre>-silent &lt;boolean&gt; (property: silent)
 * &nbsp;&nbsp;&nbsp;If enabled, then no errors are output in the console; Note: the enclosing 
 * &nbsp;&nbsp;&nbsp;actor handler must have this enabled as well.
 * &nbsp;&nbsp;&nbsp;default: false
 * </pre>
 * 
 * <pre>-output &lt;adams.core.io.PlaceholderFile&gt; (property: outputFile)
 * &nbsp;&nbsp;&nbsp;The name of the output file.
 * &nbsp;&nbsp;&nbsp;default: ${CWD}
 * </pre>
 * 
 * <pre>-pretty-printing &lt;boolean&gt; (property: prettyPrinting)
 * &nbsp;&nbsp;&nbsp;If enabled, the output is printed in a 'pretty' format.
 * &nbsp;&nbsp;&nbsp;default: false
 * </pre>
 * 
 <!-- options-end -->
 *
 * @author  fracpete (fracpete at waikato dot ac dot nz)
 * @version $Revision$
 */
public class JsonFileWriter extends AbstractFileWriter implements PrettyPrintingSupporter {

    /** for serialization. */
    private static final long serialVersionUID = 3613018887562327088L;

    /** whether to use pretty-printing. */
    protected boolean m_PrettyPrinting;

    /**
     * Returns a string describing the object.
     *
     * @return          a description suitable for displaying in the gui
     */
    @Override
    public String globalInfo() {
        return "Writes a JSON object/array to a file.";
    }

    /**
     * Adds options to the internal list of options.
     */
    public void defineOptions() {
        super.defineOptions();

        m_OptionManager.add("pretty-printing", "prettyPrinting", false);
    }

    /**
     * Returns the tip text for this property.
     *
     * @return       tip text for this property suitable for
     *          displaying in the GUI or for listing the options.
     */
    @Override
    public String outputFileTipText() {
        return "The name of the output file.";
    }

    /**
     * Sets whether to use pretty-printing or not.
     *
     * @param value   true if to use pretty-printing
     */
    public void setPrettyPrinting(boolean value) {
        m_PrettyPrinting = value;
        reset();
    }

    /**
     * Returns whether pretty-printing is used or not.
     *
     * @return      true if to use pretty-printing
     */
    public boolean getPrettyPrinting() {
        return m_PrettyPrinting;
    }

    /**
     * Returns the tip text for this property.
     *
     * @return       tip text for this property suitable for
     *          displaying in the GUI or for listing the options.
     */
    public String prettyPrintingTipText() {
        return "If enabled, the output is printed in a 'pretty' format.";
    }

    /**
     * Returns the class that the consumer accepts.
     *
     * @return      <!-- flow-accepts-start -->net.minidev.json.JSONAware.class<!-- flow-accepts-end -->
     */
    public Class[] accepts() {
        return new Class[] { JSONAware.class };
    }

    /**
     * Executes the flow item.
     *
     * @return      null if everything is fine, otherwise error message
     */
    @Override
    protected String doExecute() {
        String result;
        String content;
        Gson gson;
        JsonParser jp;
        JsonElement je;

        result = null;

        content = ((JSONAware) m_InputToken.getPayload()).toJSONString();

        if (m_PrettyPrinting) {
            gson = new GsonBuilder().setPrettyPrinting().create();
            jp = new JsonParser();
            je = jp.parse(content);
            content = gson.toJson(je);
        }

        if (!FileUtils.writeToFile(m_OutputFile.getAbsolutePath(), content, false))
            result = "Failed to write JSON file: " + m_OutputFile;

        return result;
    }
}