source: trunk/greenstone3-extensions/gs3build/src/org/greenstone/gsdl3/gs3build/extractor/MetaXMLExtractor.java@ 12188

package org.greenstone.gsdl3.gs3build.extractor;

import java.io.FileReader;

import java.net.URL;

import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;
import org.greenstone.gsdl3.gs3build.util.GS2TextFileHandler;

import org.apache.xerces.parsers.SAXParser;
import org.xml.sax.XMLReader;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.Attributes;
import org.xml.sax.helpers.XMLReaderFactory;
import org.xml.sax.helpers.DefaultHandler;

import org.greenstone.gsdl3.gs3build.doctypes.DocumentID;
import org.greenstone.gsdl3.gs3build.doctypes.DocumentInterface;
import org.greenstone.gsdl3.gs3build.doctypes.MetadataDocument;
import org.greenstone.gsdl3.gs3build.doctypes.DocumentLoader;
import org.greenstone.gsdl3.gs3build.doctypes.DocumentList;

import org.greenstone.gsdl3.gs3build.metadata.MetadataLabel;

public class MetaXMLExtractor implements ExtractorInterface
{
  /**
   *  An inner class to handle Metadata files
   */
  class MetadataHandler extends DefaultHandler
  { List         files;
    String       label;
    StringBuffer value;
    URL          url;
    boolean      inElement;
    boolean      accumulate;
    DocumentList documentList;
    List         documentIds;
    List         documents;

    MetadataHandler(DocumentList documentList)
    { super();
    
      this.label = null;
      this.value = null;
      this.documentList = documentList;
    }

    public void startElement(String URI, String localName, String qName, Attributes attributes)
    { if (localName.equals("FileName"))
      { this.value = new StringBuffer();
      }
      else if (localName.equals("FileSet"))
      { this.files = new ArrayList();
      }
      else if (localName.equals("Description"))
      { this.documentIds = this.documentList.findDocumentIdsUsingFiles(this.files, this.url.toString());    

    if (documentIds != null && documentIds.size() > 0) {
      this.documents = new ArrayList();
      
      Iterator idIterator = documentIds.iterator();
      while (idIterator.hasNext()) {
        String docIdString = idIterator.next().toString();
        DocumentID docId   = new DocumentID(docIdString);
        DocumentInterface document = documentList.getDocument(docId);
        if (document != null) {
          documents.add(document);
        }
      }
    }
      }
      else if (localName.equals("Metadata"))
      { this.label = attributes.getValue("name");
        this.value = new StringBuffer();

    String mode = attributes.getValue("mode");
    this.accumulate = mode.equals(ExtractorManager.ACCUMULATE_MODE);    
      }
    }

    public void endElement(String URI, String localName, String qName)
    { if (localName.equals("FileName"))
      { String file = this.value.toString();
        this.value = null;
    this.files.add(file);
      }
      else if (localName.equals("FileSet"))
      { // post the existing files item...
      }
      else if (localName.equals("Description"))
      {
    if (this.documents != null && documents.size() > 0) {
      // write out the modified documents
      // TODO: nicer/more generalised interface for this and related activity in
      //       extractor manager (actually, enricher manager);
      Iterator docIterator = documents.iterator();
      while (docIterator.hasNext()) {
        DocumentInterface document = (DocumentInterface) docIterator.next();

        //  System.out.println("Writing modified document " + document.getID());
        documentList.storeChangedDocument(document);
      }
    }
      }
      else if (localName.equals("Metadata"))
      { MetaXMLExtractor.postMetadata(this.url, this.files, 
                      this.label, this.value.toString(), 
                      this.accumulate);
    /*
    if (documentIds != null) {
      Iterator iterator = documentIds.iterator();
      while (iterator.hasNext()) {
        System.out.println("Matches file " + iterator.next().toString());
      }
    }
    */
    
    if (documentIds != null && documentIds.size() > 0) {
      Iterator docIterator = this.documents.iterator();
      while (docIterator.hasNext()) {
        DocumentInterface document = (DocumentInterface) docIterator.next();
        
        // Post to document
        // TODO: tailor this to posting documents to *sections* as required...
        if (accumulate) {
          document.addDocumentMetadata(new MetadataLabel(this.label), this.value.toString());
        }
        else {
          document.setDocumentMetadata(new MetadataLabel(this.label), this.value.toString());
        }
      } 
    }

    // flatten the metadata items again...
        this.value = null;
    this.label = null;
      }
    }

    public void characters(char c[], int start, int length)
    { if (this.value != null)
      { String string = new String(c, start, length);
        this.value.append(string);
      }
    }

    public void setUrl(URL url)
    { this.url = url;
    }
  }

  private DocumentList documentList;

  /**
   *  Construct of extractor
   */
  public MetaXMLExtractor()
  { // Intentionally left blank
  }

  /**
   *  This extractor doesn't need to do any preparation/completion work,
   *  so this member function is empty.
   */
  public void configure(String outputDir)
  { // Intentionally left blank
  }

  public void configure(DocumentList list)
  { this.documentList = list;
  }

  /**
   *  This extractor doesn't need to do any preparation/completion work,
   *  so this member function is empty.
   */
  public void startPass(int passNo)
  { // Intentionally left blank
  }

  /**
   *  Process the document - for a metadata document, this results in the
   *  decoration of other files, for other documents, it does nothing.
   */
  public void extractDocument(DocumentID docID, DocumentInterface document)
  { if (document.getDocumentType().equals(MetadataDocument.METADATA_DOCUMENT_TYPE))
    { // Extract the content from the metadata file
      URL url;

      try {
    SAXParser parser = new SAXParser();
    MetadataHandler handler = new MetadataHandler(this.documentList);
        /*
    XMLReader reader = XMLReaderFactory.createXMLReader();
    reader.setContentHandler(handler);
    reader.setErrorHandler(handler);*/
    parser.setContentHandler(handler);
      
    // Get path of file; we cheat here by assuming that the url is a file - this
    // really ought to be done better [TODO: fix to handle full paths & URLs]
    url = document.getDocumentFiles().getFile(0).getURL();
    String filePath = url.getPath();
    handler.setUrl(new URL(url, "."));

    // A metadata document consists of one file only - get it from the 'default'
    // file group
    /*
    FileReader fileReader = new FileReader(filePath);
    reader.parse(new InputSource(fileReader));
    */
    parser.parse(filePath);
      }
      catch (SAXException saxException)
      { // TODO: log error
    System.err.println(saxException);
      }
      catch (java.io.FileNotFoundException fileException)
      { System.err.println(fileException);
      }
      catch (java.io.IOException ioException)
      { System.err.println(ioException);
      }
      /*      catch (java.net.MalformedURLException malEx) {
    System.err.println("Unable to get parent of URL "+url.toString()+" in metadata extraction.");
    return;
      }
      */

      // for each document post it to the corresponding document
    }
  }

  protected static void postMetadata(URL url, List files, String label, String value, boolean accumulate)
  { String file;

    Iterator fileIter = files.iterator();
    while (fileIter.hasNext()) {
      file = fileIter.next().toString();

      System.out.println(url.toString() + " " + file + ": " + label + "=" + value);
    }
  }

  /**
   *  This extractor doesn't need to do any preparation/completion work,
   *  so this member function is empty.
   */
  public void endPass(int passNo)
  { // Intentionally left blank
  }

  /**
   *  This extractor is a simple, single-pass extractor
   *
   *  @see: org.greenstone.gsdl3.gs3build.extractor.ExtractorInterface:getNumberOfPasses
   */
  public int getNumberOfPasses()
  { return 1;
  }
}