FileDocCategorySizeDatePackage
FieldsWriter.javaAPI DocApache Lucene 1.94740Mon Feb 20 09:20:14 GMT 2006org.apache.lucene.index

FieldsWriter

public final class FieldsWriter extends Object
Copyright 2004 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.

Fields Summary
static final byte
FIELD_IS_TOKENIZED
static final byte
FIELD_IS_BINARY
static final byte
FIELD_IS_COMPRESSED
private FieldInfos
fieldInfos
private IndexOutput
fieldsStream
private IndexOutput
indexStream
Constructors Summary
FieldsWriter(Directory d, String segment, FieldInfos fn)


            
        fieldInfos = fn;
        fieldsStream = d.createOutput(segment + ".fdt");
        indexStream = d.createOutput(segment + ".fdx");
Methods Summary
final voidaddDocument(org.apache.lucene.document.Document doc)

        indexStream.writeLong(fieldsStream.getFilePointer());

        int storedCount = 0;
        Enumeration fields = doc.fields();
        while (fields.hasMoreElements()) {
            Field field = (Field) fields.nextElement();
            if (field.isStored())
                storedCount++;
        }
        fieldsStream.writeVInt(storedCount);

        fields = doc.fields();
        while (fields.hasMoreElements()) {
            Field field = (Field) fields.nextElement();
            if (field.isStored()) {
                fieldsStream.writeVInt(fieldInfos.fieldNumber(field.name()));

                byte bits = 0;
                if (field.isTokenized())
                    bits |= FieldsWriter.FIELD_IS_TOKENIZED;
                if (field.isBinary())
                    bits |= FieldsWriter.FIELD_IS_BINARY;
                if (field.isCompressed())
                    bits |= FieldsWriter.FIELD_IS_COMPRESSED;
                
                fieldsStream.writeByte(bits);
                
                if (field.isCompressed()) {
                  // compression is enabled for the current field
                  byte[] data = null;
                  // check if it is a binary field
                  if (field.isBinary()) {
                    data = compress(field.binaryValue());
                  }
                  else {
                    data = compress(field.stringValue().getBytes("UTF-8"));
                  }
                  final int len = data.length;
                  fieldsStream.writeVInt(len);
                  fieldsStream.writeBytes(data, len);
                }
                else {
                  // compression is disabled for the current field
                  if (field.isBinary()) {
                    byte[] data = field.binaryValue();
                    final int len = data.length;
                    fieldsStream.writeVInt(len);
                    fieldsStream.writeBytes(data, len);
                  }
                  else {
                    fieldsStream.writeString(field.stringValue());
                  }
                }
            }
        }
final voidclose()

        fieldsStream.close();
        indexStream.close();
private final byte[]compress(byte[] input)


      // Create the compressor with highest level of compression
      Deflater compressor = new Deflater();
      compressor.setLevel(Deflater.BEST_COMPRESSION);

      // Give the compressor the data to compress
      compressor.setInput(input);
      compressor.finish();

      /*
       * Create an expandable byte array to hold the compressed data.
       * You cannot use an array that's the same size as the orginal because
       * there is no guarantee that the compressed data will be smaller than
       * the uncompressed data.
       */
      ByteArrayOutputStream bos = new ByteArrayOutputStream(input.length);

      // Compress the data
      byte[] buf = new byte[1024];
      while (!compressor.finished()) {
        int count = compressor.deflate(buf);
        bos.write(buf, 0, count);
      }
      
      compressor.end();

      // Get the compressed data
      return bos.toByteArray();