source: trunk/gli/src/org/greenstone/gatherer/file/FileAssociationManager.java@ 4670

/**
 *#########################################################################
 *
 * A component of the Gatherer application, part of the Greenstone digital
 * library suite from the New Zealand Digital Library Project at the
 * University of Waikato, New Zealand.
 *
 * Author: John Thompson, Greenstone Digital Library, University of Waikato
 *
 * Copyright (C) 1999 New Zealand Digital Library Project
 *
 * 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.
 *########################################################################
 */
package org.greenstone.gatherer.file;

import java.io.*;
import org.greenstone.gatherer.Gatherer;
import org.greenstone.gatherer.gui.FileAssociationDialog;
import org.greenstone.gatherer.msm.MSMUtils;
import org.greenstone.gatherer.util.Utility;
import org.greenstone.gatherer.util.WinRegistry;
import org.w3c.dom.*;

public class FileAssociationManager {
    static final public String FILENAME_ARG = "%1";
    static final private String DATA_FILENAME = "associations.xml";
    static final private String ENTRY_ELEMENT = "Entry";
    static final private String ESCAPE = "\\\\"; // '\'
    static final private String ESCAPED_ESCAPE = "\\\\\\\\"; // '\\'
    static final private String EXTENSION_ATTRIBUTE = "extension";
    private Document document;
    private File data_file;   

    public FileAssociationManager() {
    // If a associations.xml is available in the GLI install directory load it.
    data_file = new File(Utility.BASE_DIR + DATA_FILENAME);
    if(data_file.exists()) {
        document = Utility.parse(data_file, true);
    }
    // Load the default associations xml data file. This can be done using the classloader.
    else {
        document = Utility.parse(Utility.XML_DIRECTORY + DATA_FILENAME, true);
    }
    // Initialize the associations. This involves looking through all current associations searching for those with a command of "".
    if(document != null) {
        NodeList entries = (document.getDocumentElement()).getElementsByTagName(ENTRY_ELEMENT);
        for(int i = 0; i < entries.getLength(); i++) {
        Element entry = (Element) entries.item(i);
        String extension = entry.getAttribute(EXTENSION_ATTRIBUTE);
        String command = MSMUtils.getValue(entry);
        // If we encounter a command of "", and we are on windows, we try to automatically set this command.
        if(command.length() == 0 && Utility.isWindows()) {
            // Create a dummy filename with the appropriate extension
            String dummy_file = "dummy." + extension;
            command = WinRegistry.openCommand(dummy_file);
            // If this succeeded add the association.
            if(command != null) {
            // Remember to replace the dummy filename with %1
            command = command.replaceAll(dummy_file, FILENAME_ARG);
            // Replace the text in this node.
            MSMUtils.setValue(entry, command);
            }
            dummy_file = null;
        }
        command = null;
        extension = null;
        entry = null;
        }
        entries = null;
    }
    else {
        Gatherer.println("Didn't parse anything. About to crash.");
    }
    }
    
    public void edit() {
    FileAssociationDialog dialog = new FileAssociationDialog(this);
    dialog.display(null);
    dialog = null;        
    }

    public String getCommand(File file) {
    String command = null;
    if(file.isFile()) {
        // Determine extension
        String filename = file.getAbsolutePath();
        String extension = filename.substring(filename.lastIndexOf(".") + 1);
        // Try to retrieve a value from cache
        Element entry = getCommand(extension);
        if(entry != null) {
        command = MSMUtils.getValue(entry); 
        if(command == null || command.length() == 0) {
            // If command is null, and we are on windows try searching the registry.
            if(Utility.isWindows()) {
            command = WinRegistry.openCommand(filename);
            }
            // Otherwise display the dialog and ask the user to enter launching command.
            if(command == null || command.length() == 0) {
            // Show the dialog which forces a user to select the launch command for a certain file.
            FileAssociationDialog dialog = new FileAssociationDialog(this);
            command = dialog.display(extension);
            dialog = null;
            }
            // Hopefully by now we have a command, or else we're never going to get one. Add the association.
            if(command != null) {
            // If no previous entry existed create one.
            if(entry == null) {
                entry = document.createElement(ENTRY_ELEMENT);
                entry.setAttribute(EXTENSION_ATTRIBUTE, extension);
                document.getDocumentElement().appendChild(entry);
            }
            // Replace the text in this node. Remember to replace the dummy filename with %1
            MSMUtils.setValue(entry, command.replaceAll(filename, FILENAME_ARG));
            }
        }
        if(command != null) {
            // We have to fix filename under windows to escape the backslashes.
            filename = filename.replaceAll(ESCAPE, ESCAPED_ESCAPE);
            // Replace %1 with the appropriate filename
            command = command.replaceAll(FILENAME_ARG, filename);
        }
        }
        entry = null;
        extension = null;
        filename = null;
    }
    return command;
    }

    public Element getCommand(String target_extension) {
    NodeList entries = document.getDocumentElement().getElementsByTagName(ENTRY_ELEMENT);
    for(int i = 0; i < entries.getLength(); i++) { 
        Element entry = (Element) entries.item(i);
        String extension = entry.getAttribute(EXTENSION_ATTRIBUTE);
        if(extension.equalsIgnoreCase(target_extension)) {
        entries = null;
        extension = null;
        return entry;
        }
    }
    entries = null;
    return null;
    }

    public String getCommandString(String target_extension) {
    Element entry = getCommand(target_extension);
    if(entry != null) {
        return MSMUtils.getValue(entry);
    }
    else {
        return "";
    }
    }

    public String getExtension(int index) {
    NodeList entries = document.getDocumentElement().getElementsByTagName(ENTRY_ELEMENT);
    if(0 <= index && index < entries.getLength()) {
        Element entry = (Element) entries.item(index);
        return entry.getAttribute(EXTENSION_ATTRIBUTE);
    }
    return "";
    }

    public void save() {
    Utility.export(document, data_file);
    }

    public void setCommand(String extension, String command) {
    Gatherer.println("Set Launch: " + extension + " with " + command);
    // Retrieve any existing entry for this extension
    Element entry = getCommand(extension);
    // If no previous entry existed create one.
    if(entry == null) {
        entry = document.createElement(ENTRY_ELEMENT);
        entry.setAttribute(EXTENSION_ATTRIBUTE, extension);
        document.getDocumentElement().appendChild(entry);
    }
    // Replace the text in this node. If the user has used filename instead of %1 then too bad.
    MSMUtils.setValue(entry, command);
    entry = null;
    }

    public int size() {
    NodeList entries = document.getDocumentElement().getElementsByTagName(ENTRY_ELEMENT);
    return entries.getLength();
    }
}