/*
* 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 2 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, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* JSONSaver.java
* Copyright (C) 2009 University of Waikato, Hamilton, New Zealand
*
*/
package weka.core.converters;
import weka.core.Capabilities;
import weka.core.Instances;
import weka.core.Option;
import weka.core.RevisionUtils;
import weka.core.SingleIndex;
import weka.core.Utils;
import weka.core.Capabilities.Capability;
import weka.core.json.JSONInstances;
import weka.core.json.JSONNode;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Enumeration;
import java.util.Vector;
import java.util.zip.GZIPOutputStream;
/**
<!-- globalinfo-start -->
* Writes to a destination that is in JSON format.<br/>
* The data can be compressed with gzip, in order to save space.<br/>
* <br/>
* For more information, see JSON homepage:<br/>
* http://www.json.org/
* <p/>
<!-- globalinfo-end -->
*
<!-- options-start -->
* Valid options are: <p/>
*
* <pre> -i <the input file>
* The input file</pre>
*
* <pre> -o <the output file>
* The output file</pre>
*
* <pre> -C <class index>
* The class index (first and last are valid as well).
* (default: last)</pre>
*
* <pre> -compress
* Compresses the data (uses '.json.gz' as extension instead of '.json')
* (default: off)</pre>
*
<!-- options-end -->
*
* @author FracPete (fracpete at waikato dot ac dot nz)
* @version $Revision: 5953 $
* @see Saver
*/
public class JSONSaver
extends AbstractFileSaver
implements BatchConverter {
/** for serialization. */
private static final long serialVersionUID = -1047134047244534557L;
/** the class index. */
protected SingleIndex m_ClassIndex = new SingleIndex();
/** whether to compress the output. */
protected boolean m_CompressOutput = false;
/**
* Constructor.
*/
public JSONSaver(){
resetOptions();
}
/**
* Returns a string describing this Saver.
*
* @return a description of the Saver suitable for
* displaying in the explorer/experimenter gui
*/
public String globalInfo() {
return
"Writes to a destination that is in JSON format.\n"
+ "The data can be compressed with gzip, in order to save space.\n\n"
+ "For more information, see JSON homepage:\n"
+ "http://www.json.org/";
}
/**
* Returns an enumeration describing the available options.
*
* @return an enumeration of all the available options.
*/
public Enumeration listOptions() {
Vector<Option> result;
result = new Vector<Option>();
Enumeration en = super.listOptions();
while (en.hasMoreElements())
result.addElement((Option)en.nextElement());
result.addElement(
new Option(
"\tThe class index (first and last are valid as well).\n"
+ "\t(default: last)",
"C", 1, "-C <class index>"));
result.addElement(
new Option(
"\tCompresses the data (uses '"
+ JSONLoader.FILE_EXTENSION_COMPRESSED
+ "' as extension instead of '"
+ JSONLoader.FILE_EXTENSION + "')\n"
+ "\t(default: off)",
"compress", 0, "-compress"));
return result.elements();
}
/**
* returns the options of the current setup.
*
* @return the current options
*/
public String[] getOptions(){
int i;
Vector<String> result;
String[] options;
result = new Vector<String>();
if (getClassIndex().length() != 0) {
result.add("-C");
result.add(getClassIndex());
}
if (getCompressOutput())
result.add("-compress");
options = super.getOptions();
for (i = 0; i < options.length; i++)
result.add(options[i]);
return (String[]) result.toArray(new String[result.size()]);
}
/**
* Parses the options for this object. <p/>
*
<!-- options-start -->
* Valid options are: <p/>
*
* <pre> -i <the input file>
* The input file</pre>
*
* <pre> -o <the output file>
* The output file</pre>
*
* <pre> -C <class index>
* The class index (first and last are valid as well).
* (default: last)</pre>
*
* <pre> -compress
* Compresses the data (uses '.json.gz' as extension instead of '.json')
* (default: off)</pre>
*
<!-- options-end -->
*
* @param options the options to use
* @throws Exception if setting of options fails
*/
public void setOptions(String[] options) throws Exception {
String tmpStr;
tmpStr = Utils.getOption('C', options);
if (tmpStr.length() != 0)
setClassIndex(tmpStr);
else
setClassIndex("last");
setCompressOutput(Utils.getFlag("compress", options));
super.setOptions(options);
}
/**
* Returns a description of the file type.
*
* @return a short file description
*/
public String getFileDescription() {
return "JSON data files";
}
/**
* Gets all the file extensions used for this type of file.
*
* @return the file extensions
*/
public String[] getFileExtensions() {
return new String[]{JSONLoader.FILE_EXTENSION, JSONLoader.FILE_EXTENSION_COMPRESSED};
}
/**
* Sets the destination file.
*
* @param outputFile the destination file.
* @throws IOException throws an IOException if file cannot be set
*/
public void setFile(File outputFile) throws IOException {
if (outputFile.getAbsolutePath().endsWith(JSONLoader.FILE_EXTENSION_COMPRESSED))
setCompressOutput(true);
super.setFile(outputFile);
}
/**
* Resets the Saver.
*/
public void resetOptions() {
super.resetOptions();
if (getCompressOutput())
setFileExtension(JSONLoader.FILE_EXTENSION_COMPRESSED);
else
setFileExtension(JSONLoader.FILE_EXTENSION);
}
/**
* Returns the tip text for this property.
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String classIndexTipText() {
return "Sets the class index (\"first\" and \"last\" are valid values)";
}
/**
* Get the index of the class attribute.
*
* @return the index of the class attribute
*/
public String getClassIndex() {
return m_ClassIndex.getSingleIndex();
}
/**
* Sets index of the class attribute.
*
* @param value the index of the class attribute
*/
public void setClassIndex(String value) {
m_ClassIndex.setSingleIndex(value);
}
/**
* Returns the tip text for this property.
*
* @return tip text for this property suitable for
* displaying in the explorer/experimenter gui
*/
public String compressOutputTipText() {
return "Optional compression of the output data";
}
/**
* Gets whether the output data is compressed.
*
* @return true if the output data is compressed
*/
public boolean getCompressOutput() {
return m_CompressOutput;
}
/**
* Sets whether to compress the output.
*
* @param value if truee the output will be compressed
*/
public void setCompressOutput(boolean value) {
m_CompressOutput = value;
}
/**
* Returns the Capabilities of this saver.
*
* @return the capabilities of this object
* @see Capabilities
*/
public Capabilities getCapabilities() {
Capabilities result = super.getCapabilities();
// attributes
result.enable(Capability.NOMINAL_ATTRIBUTES);
result.enable(Capability.NUMERIC_ATTRIBUTES);
result.enable(Capability.DATE_ATTRIBUTES);
result.enable(Capability.STRING_ATTRIBUTES);
result.enable(Capability.MISSING_VALUES);
// class
result.enable(Capability.NOMINAL_CLASS);
result.enable(Capability.NUMERIC_CLASS);
result.enable(Capability.DATE_CLASS);
result.enable(Capability.STRING_CLASS);
result.enable(Capability.MISSING_CLASS_VALUES);
result.enable(Capability.NO_CLASS);
return result;
}
/**
* Sets instances that should be stored.
*
* @param instances the instances
*/
public void setInstances(Instances instances) {
if (m_ClassIndex.getSingleIndex().length() != 0) {
m_ClassIndex.setUpper(instances.numAttributes() - 1);
instances.setClassIndex(m_ClassIndex.getIndex());
}
super.setInstances(instances);
}
/**
* Sets the destination output stream.
*
* @param output the output stream.
* @throws IOException throws an IOException if destination cannot be set
*/
public void setDestination(OutputStream output) throws IOException {
if (getCompressOutput())
super.setDestination(new GZIPOutputStream(output));
else
super.setDestination(output);
}
/**
* Writes a Batch of instances.
*
* @throws IOException throws IOException if saving in batch mode
* is not possible
*/
public void writeBatch() throws IOException {
if (getInstances() == null)
throw new IOException("No instances to save");
if (getRetrieval() == INCREMENTAL)
throw new IOException("Batch and incremental saving cannot be mixed.");
setRetrieval(BATCH);
setWriteMode(WRITE);
PrintWriter outW;
if ((retrieveFile() == null) && (getWriter() == null))
outW = new PrintWriter(System.out);
else
outW = new PrintWriter(getWriter());
JSONNode json = JSONInstances.toJSON(getInstances());
StringBuffer buffer = new StringBuffer();
json.toString(buffer);
outW.println(buffer.toString());
outW.flush();
if (getWriter() != null)
outW.close();
setWriteMode(WAIT);
outW = null;
resetWriter();
setWriteMode(CANCEL);
}
/**
* Returns the revision string.
*
* @return the revision
*/
public String getRevision() {
return RevisionUtils.extract("$Revision: 5953 $");
}
/**
* Main method.
*
* @param args should contain the options of a Saver.
*/
public static void main(String[] args) {
runFileSaver(new JSONSaver(), args);
}
}