gate.DocumentExporter.java Source code

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Here is the source code for gate.DocumentExporter.java

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/*
 *  Copyright (c) 1995-2014, The University of Sheffield. See the file
 *  COPYRIGHT.txt in the software or at http://gate.ac.uk/gate/COPYRIGHT.txt
 *
 *  This file is part of GATE (see http://gate.ac.uk/), and is free
 *  software, licenced under the GNU Library General Public License,
 *  Version 2, June 1991 (in the distribution as file licence.html,
 *  and also available at http://gate.ac.uk/gate/licence.html).
 *
 *  Mark A. Greenwood 11/07/2014
 *
 */

package gate;

import gate.creole.AbstractResource;
import gate.util.ExtensionFileFilter;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import javax.swing.filechooser.FileFilter;

import org.apache.commons.io.IOUtils;

/**
 * Adds support for exporting documents from GATE. Subclasses of
 * DocumentExporter now how to export in a given format. These exporters
 * are loaded as Creole resources and made easily available within the
 * GUI, but can also be easily accessed from within the API.
 */
public abstract class DocumentExporter extends AbstractResource {

    private static final long serialVersionUID = -4810523902750051704L;

    protected String fileType, defaultExtension, mimeType;

    protected FileFilter filter;

    /**
     * Creates a new exporter instance for a given file type with default
     * extension.
     * 
     * @param fileType this is the human readable file type name that will
     *          appear on the menu
     * @param defaultExtension the default file extension for this type
     */
    public DocumentExporter(String fileType, String defaultExtension, String mimeType) {
        this.fileType = fileType;
        this.defaultExtension = defaultExtension;
        this.mimeType = mimeType;
    }

    /**
     * The name of the file type exported
     * 
     * @return the name of the file type exported
     */
    public String getFileType() {
        return fileType;
    }

    /**
     * The default extension added to files saved in this format
     * 
     * @return the default extension added to files saved in this format
     */
    public String getDefaultExtension() {
        return defaultExtension;
    }

    @Override
    public String getName() {
        return fileType;
    }

    public String getMimeType() {
        return mimeType;
    }

    /**
     * A filter used in the file chooser to restrict the view to files of
     * this type. The default implementation just uses the default
     * extension as the filter constraint
     */
    public FileFilter getFileFilter() {
        if (filter == null)
            filter = new ExtensionFileFilter(fileType + " Files (*." + defaultExtension + ")", defaultExtension);
        return filter;
    }

    /**
     * Equivalent to {@link #export(Document,File,FeatureMap)} with an empty map
     * of options.
     */
    public void export(Document doc, File file) throws IOException {
        export(doc, file, Factory.newFeatureMap());
    }

    /**
     * Equivalent to {@link #export(Document,OutputStream,FeatureMap)} using a
     * FileOutputStream instance constructed from the File param.
     */
    public void export(Document doc, File file, FeatureMap options) throws IOException {
        FileOutputStream out = null;
        try {
            out = new FileOutputStream(file);
            export(doc, new FileOutputStream(file), options);
            out.flush();
        } finally {
            IOUtils.closeQuietly(out);
        }
    }

    /**
     * Equivalent to {@link #export(Document,OutputStream)} with an empty
     * map of options.
     */
    public void export(Document doc, OutputStream out) throws IOException {
        export(doc, out, Factory.newFeatureMap());
    }

    /**
     * Exports the provided {@link Document} instance to the specified
     * {@link OutputStream} using the specified options.
     * 
     * @param doc the document to export
     * @param out the OutputStream to export the document to
     * @param options DocumentExporter specific options
     */
    public abstract void export(Document doc, OutputStream out, FeatureMap options) throws IOException;

    public static DocumentExporter getInstance(String className) {
        return (DocumentExporter) Gate.getCreoleRegister().get(className).getInstantiations().iterator().next();
    }
}