source: main/trunk/gli/src/org/greenstone/gatherer/metadata/MetadataXMLFileManager.java@ 23410

/**
 *############################################################################
 * A component of the Greenstone Librarian Interface, part of the Greenstone
 * digital library suite from the New Zealand Digital Library Project at the
 * University of Waikato, New Zealand.
 *
 * Author: Michael Dewsnip, NZDL Project, University of Waikato, NZ
 *
 * Copyright (C) 2005 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.metadata;


import java.io.*;
import java.util.*;
import org.greenstone.gatherer.DebugStream;
import org.greenstone.gatherer.Gatherer;
import org.greenstone.gatherer.collection.CollectionManager;
import org.greenstone.gatherer.collection.CollectionTreeNode;
import org.greenstone.gatherer.remote.RemoteGreenstoneServer;
import org.greenstone.gatherer.util.XMLTools;


/** This class is a static class that manages the metadata.xml files */
public class MetadataXMLFileManager
{
    static private ArrayList metadata_xml_files = new ArrayList();
    /** The objects listening for MetadataChanged events. */
    static private ArrayList metadata_changed_listeners = new ArrayList();
    /** Keep track of which metadata.xml files have been modified so we can upload them to the server */
    static private ArrayList modified_metadata_xml_files = new ArrayList();

  /** For non-accumulating metadata (gs.FilenameEncoding), need the metadata.xml files
   * sorted in top-down folder level order, which is achieved through this Comparator. 
   * By declaring a static class member here, we avoid recreating this object for every 
   * comparison, which would otherwise have resulted in a constructor call each time. */
  static private MetadataXMLFileComparator metadataXMLFileComparator = new MetadataXMLFileComparator();


    static public void addMetadata(CollectionTreeNode file_node, ArrayList metadata_values)
    {
    addMetadata(new CollectionTreeNode[] { file_node }, metadata_values);
    }


    static public void addMetadata(CollectionTreeNode[] file_nodes, MetadataValue metadata_value)
    {
    ArrayList metadata_values = new ArrayList();
    metadata_values.add(metadata_value);
    addMetadata(file_nodes, metadata_values);
    }


    static public void addMetadata(CollectionTreeNode[] file_nodes, ArrayList metadata_values)
    {
    // Check the list of metadata values is non-empty
    if (metadata_values.isEmpty()) {
        return;
    }

    // Add the metadata to each file node in turn
    for (int i = 0; i < file_nodes.length; i++) {
        File current_file = file_nodes[i].getFile();
        DebugStream.println("Adding metadata to " + current_file.getAbsolutePath());

        // Find which metadata.xml file needs editing
        boolean applicable_metadata_xml_file_found = false;
        File current_file_directory = (current_file.isDirectory() ? current_file : current_file.getParentFile());
        String current_file_directory_path = current_file_directory.getAbsolutePath();
        for (int j = 0; j < metadata_xml_files.size(); j++) {
        MetadataXMLFile metadata_xml_file = (MetadataXMLFile) metadata_xml_files.get(j);

        // This metadata.xml file is only applicable if it is at the same level as the file
        if (current_file_directory_path.equals(metadata_xml_file.getParentFile().getAbsolutePath())) {
            applicable_metadata_xml_file_found = true;
            metadata_xml_file.addMetadata(current_file, metadata_values);
            if (!modified_metadata_xml_files.contains(metadata_xml_file)) {
            modified_metadata_xml_files.add(metadata_xml_file);
            }
        }
        }

        // If no applicable metadata.xml file exists, we have to create a new one
        if (!applicable_metadata_xml_file_found) {
        // Create a new (empty) metadata.xml file in the file's directory...
        File new_metadata_xml_file_file = new File(current_file_directory, "metadata.xml");
        XMLTools.writeXMLFile(new_metadata_xml_file_file, XMLTools.parseXMLFile("xml/metadata.xml", true));

        // ...load it...
        MetadataXMLFile new_metadata_xml_file = loadMetadataXMLFile(new_metadata_xml_file_file,true);

        // ...and add the metadata
        new_metadata_xml_file.addMetadata(current_file, metadata_values);
        if (!modified_metadata_xml_files.contains(new_metadata_xml_file)) {
            modified_metadata_xml_files.add(new_metadata_xml_file);
        }
        }
    }

    // Let any listeners know that the metadata has changed
    fireMetadataChangedEvent(file_nodes);
    }


    static public void addMetadataChangedListener(MetadataChangedListener metadata_changed_listener)
    {
    metadata_changed_listeners.add(metadata_changed_listener);
    }


    static public void clearMetadataXMLFiles()
    {
    metadata_xml_files.clear();
    }


    static private void fireMetadataChangedEvent(CollectionTreeNode[] file_nodes)
    {
    // Send the event off to all the MetadataChangedListeners
    for (int i = 0; i < metadata_changed_listeners.size(); i++) {
        ((MetadataChangedListener) metadata_changed_listeners.get(i)).metadataChanged(file_nodes);
    }
    }


    /** Returns the metadata assigned to a file outside the collection, excluding folder-level/inherited metadata. */
    static public ArrayList getMetadataAssignedDirectlyToExternalFile(File file)
    {
    DebugStream.println("Getting metadata assigned directly to external file " + file + "...");

    // Build up a list of applicable metadata.xml files
    ArrayList applicable_metadata_xml_files = new ArrayList();

    File directory = (file.isDirectory() ? file : file.getParentFile());
    while (directory != null) {
        File metadata_xml_file = new File(directory, "metadata.xml");
        if (metadata_xml_file.exists() && !metadata_xml_file.isDirectory()) {
        // It is very important that shallower files come before deeper ones
        applicable_metadata_xml_files.add(0, new MetadataXMLFile(metadata_xml_file.getAbsolutePath()));
        }

        directory = directory.getParentFile();
    }

    // Get the metadata assigned to the specified file from the applicable metadata.xml files
    ArrayList assigned_metadata = getMetadataAssignedToFile(file, applicable_metadata_xml_files);

    // Remove any folder-level metadata
    for (int i = assigned_metadata.size() - 1; i >= 0; i--) {
        if (((MetadataValue) assigned_metadata.get(i)).isInheritedMetadata()) {
        assigned_metadata.remove(i);
        }
    }

    return assigned_metadata;
    }


    /** Returns the metadata assigned to a file inside the collection, excluding folder-level/inherited metadata. */
    static public ArrayList getMetadataAssignedDirectlyToFile(File file)
    {
    // Get all the metadata assigned to the specified file...
    ArrayList assigned_metadata = getMetadataAssignedToFile(file);

    // ...then remove any folder-level metadata
    for (int i = assigned_metadata.size() - 1; i >= 0; i--) {
        if (((MetadataValue) assigned_metadata.get(i)).isInheritedMetadata()) {
        assigned_metadata.remove(i);
        }
    }

    return assigned_metadata;
    }


    /** Returns all the metadata assigned to a file inside the collection. */
    static public ArrayList getMetadataAssignedToFile(File file)
    {
    // Build up a list of applicable metadata.xml files
    ArrayList applicable_metadata_xml_files = new ArrayList();

    // Look at each loaded metadata.xml file to see if it is potentially applicable
    String file_directory_path = (file.isDirectory() ? file : file.getParentFile()).getAbsolutePath() + File.separator;
    for (int i = 0; i < metadata_xml_files.size(); i++) {
        MetadataXMLFile metadata_xml_file = (MetadataXMLFile) metadata_xml_files.get(i);

        // This metadata.xml file is only potentially applicable if it is above or at the same level as the file
        if (file_directory_path.startsWith(metadata_xml_file.getParentFile().getAbsolutePath() + File.separator)) {
        applicable_metadata_xml_files.add(metadata_xml_file);
        }
    }

    // sort the metadataxml files in order starting from those in the 
    // topmost folders down to the one in the lowest level folder.
    Collections.sort(applicable_metadata_xml_files, metadataXMLFileComparator);
    // Return the metadata assigned to the specified file from the applicable metadata.xml files
    return getMetadataAssignedToFile(file, applicable_metadata_xml_files);
    }


    static private ArrayList getMetadataAssignedToFile(File file, ArrayList applicable_metadata_xml_files)
    {
    // Build up a list of metadata values assigned to this file
    ArrayList metadata_values_all = new ArrayList();

    // Look at each applicable metadata.xml file to see if it assigns metadata to this file
    for (int i = 0; i < applicable_metadata_xml_files.size(); i++) {
        MetadataXMLFile metadata_xml_file = (MetadataXMLFile) applicable_metadata_xml_files.get(i);
        DebugStream.println("Applicable metadata.xml file: " + metadata_xml_file);

        ArrayList metadata_values = metadata_xml_file.getMetadataAssignedToFile(file);
        for (int j = 0; j < metadata_values.size(); j++) {
        MetadataValue metadata_value = (MetadataValue) metadata_values.get(j);

        // Overriding metadata: remove any values with this metadata element
        if (metadata_value.isAccumulatingMetadata() == false) {
            for (int k = metadata_values_all.size() - 1; k >= 0; k--) {
            if (((MetadataValue) metadata_values_all.get(k)).getMetadataElement().equals(metadata_value.getMetadataElement())) {
                metadata_values_all.remove(k);
            }
            }
        }

        metadata_values_all.add(metadata_value);
        }
    }

    return metadata_values_all;
    }


    static public void loadMetadataXMLFiles(File directory, boolean skimfile)
    {
    // Make sure the directory (import) exists
    if (directory.exists() == false) {
        return;
    }

    // Look recursively at each subfile of the directory for metadata.xml files
    File[] directory_files = directory.listFiles();
    for (int i = 0; i < directory_files.length; i++) {
        File child_file = directory_files[i];
        if (child_file.isDirectory()) {
        loadMetadataXMLFiles(child_file,skimfile);
        }
        else if (child_file.getName().equals("metadata.xml")) {
        loadMetadataXMLFile(child_file,skimfile);
        }
    }
    }


    static private MetadataXMLFile loadMetadataXMLFile(File metadata_xml_file_file, boolean skimfile)
    {
    MetadataXMLFile metadata_xml_file = new MetadataXMLFile(metadata_xml_file_file.getAbsolutePath());
    if (metadata_xml_files.contains(metadata_xml_file)) {
        // This metadata.xml file has already been loaded, so return the loaded object
        return (MetadataXMLFile) metadata_xml_files.get(metadata_xml_files.indexOf(metadata_xml_file));
    }
    if(skimfile){
       metadata_xml_file.skimFile();
    }
    metadata_xml_files.add(metadata_xml_file);
    return metadata_xml_file;
    }


    static public void removeMetadata(CollectionTreeNode file_node, ArrayList metadata_values)
    {
    removeMetadata(new CollectionTreeNode[] { file_node }, metadata_values);
    }


    static public void removeMetadata(CollectionTreeNode[] file_nodes, MetadataValue metadata_value)
    {
    ArrayList metadata_values = new ArrayList();
    metadata_values.add(metadata_value);
    removeMetadata(file_nodes, metadata_values);
    }


    static public void removeMetadata(CollectionTreeNode[] file_nodes, ArrayList metadata_values)
    {
    // Check the list of metadata values is non-empty
    if (metadata_values.isEmpty()) {
        return;
    }

    // Remove the metadata from each file node in turn
    for (int i = 0; i < file_nodes.length; i++) {
        File current_file = file_nodes[i].getFile();
        DebugStream.println("Removing metadata from " + current_file.getAbsolutePath());

        // Find which metadata.xml file needs editing
        File current_file_directory = (current_file.isDirectory() ? current_file : current_file.getParentFile());
        String current_file_directory_path = current_file_directory.getAbsolutePath();
        for (int j = 0; j < metadata_xml_files.size(); j++) {
        MetadataXMLFile metadata_xml_file = (MetadataXMLFile) metadata_xml_files.get(j);

        // This metadata.xml file is only potentially applicable if it is above or at the same level as the file
        if (current_file_directory_path.startsWith(metadata_xml_file.getParentFile().getAbsolutePath())) {
            metadata_xml_file.removeMetadata(current_file, metadata_values);
            if (!modified_metadata_xml_files.contains(metadata_xml_file)) {
            modified_metadata_xml_files.add(metadata_xml_file);
            }
        }
        }
    }

    // Let any listeners know that the metadata has changed
    fireMetadataChangedEvent(file_nodes);
    }


    static public void removeMetadataChangedListener(MetadataChangedListener metadata_changed_listener)
    {
    metadata_changed_listeners.remove(metadata_changed_listener);
    }


    static public void replaceMetadata(CollectionTreeNode[] file_nodes, MetadataValue old_metadata_value, MetadataValue new_metadata_value)
    {
    // Replace the metadata in each file node in turn
    for (int i = 0; i < file_nodes.length; i++) {
        File current_file = file_nodes[i].getFile();
        DebugStream.println("Replacing metadata in " + current_file.getAbsolutePath());

        // Find which metadata.xml file needs editing
        File current_file_directory = (current_file.isDirectory() ? current_file : current_file.getParentFile());
        String current_file_directory_path = current_file_directory.getAbsolutePath();
        for (int j = 0; j < metadata_xml_files.size(); j++) {
        MetadataXMLFile metadata_xml_file = (MetadataXMLFile) metadata_xml_files.get(j);

        // This metadata.xml file is only applicable if it is at the same level as the file
        if (current_file_directory_path.equals(metadata_xml_file.getParentFile().getAbsolutePath())) {
            metadata_xml_file.replaceMetadata(current_file, old_metadata_value, new_metadata_value);
            if (!modified_metadata_xml_files.contains(metadata_xml_file)) {
            modified_metadata_xml_files.add(metadata_xml_file);
            }
        }
        }
    }

    // Let any listeners know that the metadata has changed
    fireMetadataChangedEvent(file_nodes);
    }


    /** Ensures that all the metadata is written to metadata.xml files. */
    static public void saveMetadataXMLFiles()
    {
    // Save the file currently loaded into memory out to disk
    MetadataXMLFile.saveLoadedFile();

    // If the collection is stored on a remote server, upload all the modified files now
    if (Gatherer.isGsdlRemote) {
        if (modified_metadata_xml_files.isEmpty()) {
        DebugStream.println("No modified metadata.xml files to upload.");
        return;
        }

        // Upload the files modified since last time, then reset the list
        Gatherer.remoteGreenstoneServer.uploadCollectionFiles(
                  CollectionManager.getLoadedCollectionName(), (File[]) modified_metadata_xml_files.toArray(new File[0]));
        modified_metadata_xml_files.clear();
    }
    }


    static public void unloadMetadataXMLFile(File metadata_xml_file_file)
    {
    DebugStream.println("Unloading metadata.xml file " + metadata_xml_file_file);

    // Find the metadata.xml file in the list of loaded files, and remove it
    for (int i = 0; i < metadata_xml_files.size(); i++) {
        MetadataXMLFile metadata_xml_file = (MetadataXMLFile) metadata_xml_files.get(i);
        if (metadata_xml_file_file.getAbsolutePath().equals(metadata_xml_file.getAbsolutePath())) {
        metadata_xml_files.remove(i);
        break;
        }
    }
    }

  
  /**
  * Comparator to order MetadataXMLFiles in ascending order from
  * those in a higher level folder to those in a lower level folder
  * It is based on the assumption that all MetadataXMLFiles sent to
  * it to compare will be linear descendants of one toplevel folder
  * E.g. /A/metadata.xml, /A/B/metadata.xml, /A/B/C/D/metadata.xml.
  * In other words, that each is a substring of one other until we
  * get to the toplevel folder.
  */
  private static class MetadataXMLFileComparator implements Comparator {
    
    public int compare(Object o1, Object o2) {
      if(!(o1 instanceof MetadataXMLFile)) {
    return -1;
      } else if (!(o2 instanceof MetadataXMLFile)) {
    return 1;
      } 

      // Both are MetadataXMLFiles objects. Remove the terminating
      // "metadata.xml" from their filenames to get their containing folder
      String filename1 = ((MetadataXMLFile)o1).getParentFile().getAbsolutePath();
      String filename2 = ((MetadataXMLFile)o2).getParentFile().getAbsolutePath();

      // if 1 is a prefix 2, then 1 < 2 in the ordering (1 comes before 2)
      if(filename2.startsWith(filename1)) {
    return -1;
      } else if(filename1.startsWith(filename2)) {
    return 1;
      } else { 
    // unlikely that the metadata.xml files will be the same
    // or that neither is a prefix of the other
    return filename1.compareTo(filename2); // sorts in ascending order
      }      
      
    }

    public boolean equals(Object obj) {
      if(!(obj instanceof MetadataXMLFileComparator)) {
    return false;
      } 
     
      // else it is the same sort of comparator
      return true;
    }

  }

}