package org.apache.lucene.index;
/**
* Copyright 2007 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.
*/
/**
* The TermVectorMapper can be used to map Term Vectors into your own
* structure instead of the parallel array structure used by
* {@link org.apache.lucene.index.IndexReader#getTermFreqVector(int,String)}.
* <p/>
* It is up to the implementation to make sure it is thread-safe.
*
*
**/
public abstract class TermVectorMapper {
private boolean ignoringPositions;
private boolean ignoringOffsets;
protected TermVectorMapper() {
}
/**
*
* @param ignoringPositions true if this mapper should tell Lucene to ignore positions even if they are stored
* @param ignoringOffsets similar to ignoringPositions
*/
protected TermVectorMapper(boolean ignoringPositions, boolean ignoringOffsets) {
this.ignoringPositions = ignoringPositions;
this.ignoringOffsets = ignoringOffsets;
}
/**
* Tell the mapper what to expect in regards to field, number of terms, offset and position storage.
* This method will be called once before retrieving the vector for a field.
*
* This method will be called before {@link #map(String,int,TermVectorOffsetInfo[],int[])}.
* @param field The field the vector is for
* @param numTerms The number of terms that need to be mapped
* @param storeOffsets true if the mapper should expect offset information
* @param storePositions true if the mapper should expect positions info
*/
public abstract void setExpectations(String field, int numTerms, boolean storeOffsets, boolean storePositions);
/**
* Map the Term Vector information into your own structure
* @param term The term to add to the vector
* @param frequency The frequency of the term in the document
* @param offsets null if the offset is not specified, otherwise the offset into the field of the term
* @param positions null if the position is not specified, otherwise the position in the field of the term
*/
public abstract void map(String term, int frequency, TermVectorOffsetInfo [] offsets, int [] positions);
/**
* Indicate to Lucene that even if there are positions stored, this mapper is not interested in them and they
* can be skipped over. Derived classes should set this to true if they want to ignore positions. The default
* is false, meaning positions will be loaded if they are stored.
* @return false
*/
public boolean isIgnoringPositions()
{
return ignoringPositions;
}
/**
*
* @see #isIgnoringPositions() Same principal as {@link #isIgnoringPositions()}, but applied to offsets. false by default.
* @return false
*/
public boolean isIgnoringOffsets()
{
return ignoringOffsets;
}
/**
* Passes down the index of the document whose term vector is currently being mapped,
* once for each top level call to a term vector reader.
*<p/>
* Default implementation IGNORES the document number. Override if your implementation needs the document number.
* <p/>
* NOTE: Document numbers are internal to Lucene and subject to change depending on indexing operations.
*
* @param documentNumber index of document currently being mapped
*/
public void setDocumentNumber(int documentNumber) {
}
}