org.apache.lucene.index.FieldInvertState Maven / Gradle / Ivy
/*
* 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.
*/
package org.apache.lucene.index;
import org.apache.lucene.analysis.TokenStream; // javadocs
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PayloadAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.analysis.tokenattributes.TermToBytesRefAttribute;
import org.apache.lucene.util.AttributeSource;
/**
* This class tracks the number and position / offset parameters of terms
* being added to the index. The information collected in this class is
* also used to calculate the normalization factor for a field.
*
* @lucene.experimental
*/
public final class FieldInvertState {
String name;
int position;
int length;
int numOverlap;
int offset;
int maxTermFrequency;
int uniqueTermCount;
float boost;
// we must track these across field instances (multi-valued case)
int lastStartOffset = 0;
int lastPosition = 0;
AttributeSource attributeSource;
OffsetAttribute offsetAttribute;
PositionIncrementAttribute posIncrAttribute;
PayloadAttribute payloadAttribute;
TermToBytesRefAttribute termAttribute;
/** Creates {code FieldInvertState} for the specified
* field name. */
public FieldInvertState(String name) {
this.name = name;
}
/** Creates {code FieldInvertState} for the specified
* field name and values for all fields. */
public FieldInvertState(String name, int position, int length, int numOverlap, int offset, float boost) {
this.name = name;
this.position = position;
this.length = length;
this.numOverlap = numOverlap;
this.offset = offset;
this.boost = boost;
}
/**
* Re-initialize the state
*/
void reset() {
position = -1;
length = 0;
numOverlap = 0;
offset = 0;
maxTermFrequency = 0;
uniqueTermCount = 0;
boost = 1.0f;
lastStartOffset = 0;
lastPosition = 0;
}
// TODO: better name?
/**
* Sets attributeSource to a new instance.
*/
void setAttributeSource(AttributeSource attributeSource) {
if (this.attributeSource != attributeSource) {
this.attributeSource = attributeSource;
termAttribute = attributeSource.getAttribute(TermToBytesRefAttribute.class);
posIncrAttribute = attributeSource.addAttribute(PositionIncrementAttribute.class);
offsetAttribute = attributeSource.addAttribute(OffsetAttribute.class);
payloadAttribute = attributeSource.getAttribute(PayloadAttribute.class);
}
}
/**
* Get the last processed term position.
* @return the position
*/
public int getPosition() {
return position;
}
/**
* Get total number of terms in this field.
* @return the length
*/
public int getLength() {
return length;
}
/** Set length value. */
public void setLength(int length) {
this.length = length;
}
/**
* Get the number of terms with positionIncrement == 0.
* @return the numOverlap
*/
public int getNumOverlap() {
return numOverlap;
}
/** Set number of terms with {@code positionIncrement ==
* 0}. */
public void setNumOverlap(int numOverlap) {
this.numOverlap = numOverlap;
}
/**
* Get end offset of the last processed term.
* @return the offset
*/
public int getOffset() {
return offset;
}
/**
* Get boost value. This is the cumulative product of
* document boost and field boost for all field instances
* sharing the same field name.
* @return the boost
*/
public float getBoost() {
return boost;
}
/** Set boost value. */
public void setBoost(float boost) {
this.boost = boost;
}
/**
* Get the maximum term-frequency encountered for any term in the field. A
* field containing "the quick brown fox jumps over the lazy dog" would have
* a value of 2, because "the" appears twice.
*/
public int getMaxTermFrequency() {
return maxTermFrequency;
}
/**
* Return the number of unique terms encountered in this field.
*/
public int getUniqueTermCount() {
return uniqueTermCount;
}
/** Returns the {@link AttributeSource} from the {@link
* TokenStream} that provided the indexed tokens for this
* field. */
public AttributeSource getAttributeSource() {
return attributeSource;
}
/**
* Return the field's name
*/
public String getName() {
return name;
}
}