/* * Copyright 1999-2005 The Apache Software Foundation. *  * 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 org.apache.log4j.chainsaw;import java.awt.event.ActionEvent;import java.io.File;import java.io.IOException;import java.io.StringReader;import javax.swing.AbstractAction;import javax.swing.JFileChooser;import javax.swing.JFrame;import javax.swing.JOptionPane;import javax.xml.parsers.ParserConfigurationException;import javax.xml.parsers.SAXParserFactory;import org.apache.log4j.Logger;import org.xml.sax.InputSource;import org.xml.sax.SAXException;import org.xml.sax.XMLReader;/** * Encapsulates the action to load an XML file. * * @author <a href="mailto:oliver@puppycrawl.com">Oliver Burn</a> * @version 1.0 */class LoadXMLAction    extends AbstractAction{    /** use to log messages **/    private static final Logger LOG = Logger.getLogger(LoadXMLAction.class);    /** the parent frame **/    private final JFrame mParent;    /**     * the file chooser - configured to allow only the selection of a     * single file.     */    private final JFileChooser mChooser = new JFileChooser();    {        mChooser.setMultiSelectionEnabled(false);        mChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);    }    /** parser to read XML files **/    private final XMLReader mParser;    /** the content handler **/    private final XMLFileHandler mHandler;    /**     * Creates a new <code>LoadXMLAction</code> instance.     *     * @param aParent the parent frame     * @param aModel the model to add events to     * @exception SAXException if an error occurs     * @throws ParserConfigurationException if an error occurs     */    LoadXMLAction(JFrame aParent, MyTableModel aModel)        throws SAXException, ParserConfigurationException    {        mParent = aParent;        mHandler = new XMLFileHandler(aModel);        mParser = SAXParserFactory.newInstance().newSAXParser().getXMLReader();        mParser.setContentHandler(mHandler);    }    /**     * Prompts the user for a file to load events from.     * @param aIgnore an <code>ActionEvent</code> value     */    public void actionPerformed(ActionEvent aIgnore) {        LOG.info("load file called");        if (mChooser.showOpenDialog(mParent) == JFileChooser.APPROVE_OPTION) {            LOG.info("Need to load a file");            final File chosen = mChooser.getSelectedFile();            LOG.info("loading the contents of " + chosen.getAbsolutePath());            try {                final int num = loadFile(chosen.getAbsolutePath());                JOptionPane.showMessageDialog(                    mParent,                    "Loaded " + num + " events.",                    "CHAINSAW",                    JOptionPane.INFORMATION_MESSAGE);            } catch (Exception e) {                LOG.warn("caught an exception loading the file", e);                JOptionPane.showMessageDialog(                    mParent,                    "Error parsing file - " + e.getMessage(),                    "CHAINSAW",                    JOptionPane.ERROR_MESSAGE);            }        }    }    /**     * Loads the contents of file into the model     *     * @param aFile the file to extract events from     * @return the number of events loaded     * @throws SAXException if an error occurs     * @throws IOException if an error occurs     */    private int loadFile(String aFile)        throws SAXException, IOException    {        synchronized (mParser) {            // Create a dummy document to parse the file            final StringBuffer buf = new StringBuffer();            buf.append("<?xml version=\"1.0\" standalone=\"yes\"?>\n");            buf.append("<!DOCTYPE log4j:eventSet ");            buf.append("[<!ENTITY data SYSTEM \"file:///");            buf.append(aFile);            buf.append("\">]>\n");            buf.append("<log4j:eventSet xmlns:log4j=\"Claira\">\n");            buf.append("&data;\n");            buf.append("</log4j:eventSet>\n");            final InputSource is =                new InputSource(new StringReader(buf.toString()));            mParser.parse(is);            return mHandler.getNumEvents();        }    }}