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Lucene example source code file (DocInverterPerField.java)

This example Lucene source code file (DocInverterPerField.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

docfieldconsumerperfield, docinverterperfield, docinverterperfield, fieldable, fieldinfo, inverteddocconsumerperfield, io, ioexception, override, reader, reader, string, string, tokenstream, tokenstream

The Lucene DocInverterPerField.java source code

package org.apache.lucene.index;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

import java.io.IOException;
import java.io.Reader;
import org.apache.lucene.document.Fieldable;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;

/**
 * Holds state for inverting all occurrences of a single
 * field in the document.  This class doesn't do anything
 * itself; instead, it forwards the tokens produced by
 * analysis to its own consumer
 * (InvertedDocConsumerPerField).  It also interacts with an
 * endConsumer (InvertedDocEndConsumerPerField).
 */

final class DocInverterPerField extends DocFieldConsumerPerField {

  final private DocInverterPerThread perThread;
  final private FieldInfo fieldInfo;
  final InvertedDocConsumerPerField consumer;
  final InvertedDocEndConsumerPerField endConsumer;
  final DocumentsWriter.DocState docState;
  final FieldInvertState fieldState;

  public DocInverterPerField(DocInverterPerThread perThread, FieldInfo fieldInfo) {
    this.perThread = perThread;
    this.fieldInfo = fieldInfo;
    docState = perThread.docState;
    fieldState = perThread.fieldState;
    this.consumer = perThread.consumer.addField(this, fieldInfo);
    this.endConsumer = perThread.endConsumer.addField(this, fieldInfo);
  }

  @Override
  void abort() {
    try {
      consumer.abort();
    } finally {
      endConsumer.abort();
    }
  }

  @Override
  public void processFields(final Fieldable[] fields,
                            final int count) throws IOException {

    fieldState.reset(docState.doc.getBoost());

    final int maxFieldLength = docState.maxFieldLength;

    final boolean doInvert = consumer.start(fields, count);

    for(int i=0;i<count;i++) {

      final Fieldable field = fields[i];

      // TODO FI: this should be "genericized" to querying
      // consumer if it wants to see this particular field
      // tokenized.
      if (field.isIndexed() && doInvert) {
        
        if (i > 0)
          fieldState.position += docState.analyzer.getPositionIncrementGap(fieldInfo.name);

        if (!field.isTokenized()) {		  // un-tokenized field
          String stringValue = field.stringValue();
          final int valueLength = stringValue.length();
          perThread.singleToken.reinit(stringValue, 0, valueLength);
          fieldState.attributeSource = perThread.singleToken;
          consumer.start(field);

          boolean success = false;
          try {
            consumer.add();
            success = true;
          } finally {
            if (!success)
              docState.docWriter.setAborting();
          }
          fieldState.offset += valueLength;
          fieldState.length++;
          fieldState.position++;
        } else {                                  // tokenized field
          final TokenStream stream;
          final TokenStream streamValue = field.tokenStreamValue();

          if (streamValue != null) 
            stream = streamValue;
          else {
            // the field does not have a TokenStream,
            // so we have to obtain one from the analyzer
            final Reader reader;			  // find or make Reader
            final Reader readerValue = field.readerValue();

            if (readerValue != null)
              reader = readerValue;
            else {
              String stringValue = field.stringValue();
              if (stringValue == null)
                throw new IllegalArgumentException("field must have either TokenStream, String or Reader value");
              perThread.stringReader.init(stringValue);
              reader = perThread.stringReader;
            }
          
            // Tokenize field and add to postingTable
            stream = docState.analyzer.reusableTokenStream(fieldInfo.name, reader);
          }

          // reset the TokenStream to the first token
          stream.reset();

          final int startLength = fieldState.length;
          
          try {
            boolean hasMoreTokens = stream.incrementToken();

            fieldState.attributeSource = stream;

            OffsetAttribute offsetAttribute = fieldState.attributeSource.addAttribute(OffsetAttribute.class);
            PositionIncrementAttribute posIncrAttribute = fieldState.attributeSource.addAttribute(PositionIncrementAttribute.class);
            
            consumer.start(field);
            
            for(;;) {

              // If we hit an exception in stream.next below
              // (which is fairly common, eg if analyzer
              // chokes on a given document), then it's
              // non-aborting and (above) this one document
              // will be marked as deleted, but still
              // consume a docID
              
              if (!hasMoreTokens) break;
              
              final int posIncr = posIncrAttribute.getPositionIncrement();
              fieldState.position += posIncr;
              if (fieldState.position > 0) {
                fieldState.position--;
              }

              if (posIncr == 0)
                fieldState.numOverlap++;

              boolean success = false;
              try {
                // If we hit an exception in here, we abort
                // all buffered documents since the last
                // flush, on the likelihood that the
                // internal state of the consumer is now
                // corrupt and should not be flushed to a
                // new segment:
                consumer.add();
                success = true;
              } finally {
                if (!success)
                  docState.docWriter.setAborting();
              }
              fieldState.position++;
              if (++fieldState.length >= maxFieldLength) {
                if (docState.infoStream != null)
                  docState.infoStream.println("maxFieldLength " +maxFieldLength+ " reached for field " + fieldInfo.name + ", ignoring following tokens");
                break;
              }

              hasMoreTokens = stream.incrementToken();
            }
            // trigger streams to perform end-of-stream operations
            stream.end();
            
            fieldState.offset += offsetAttribute.endOffset();
          } finally {
            stream.close();
          }
        }

        fieldState.offset += docState.analyzer.getOffsetGap(field);
        fieldState.boost *= field.getBoost();
      }

      // LUCENE-2387: don't hang onto the field, so GC can
      // reclaim
      fields[i] = null;
    }

    consumer.finish();
    endConsumer.finish();
  }
}

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