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package org.apache.lucene.analysis.tokenattributes;
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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import java.io.Serializable;
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import org.apache.lucene.analysis.TokenStream;
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import org.apache.lucene.util.AttributeImpl;
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/** The positionIncrement determines the position of this token
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* relative to the previous Token in a {@link TokenStream}, used in phrase
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* <p>The default value is one.
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* <p>Some common uses for this are:<ul>
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* <li>Set it to zero to put multiple terms in the same position. This is
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* useful if, e.g., a word has multiple stems. Searches for phrases
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* including either stem will match. In this case, all but the first stem's
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* increment should be set to zero: the increment of the first instance
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* should be one. Repeating a token with an increment of zero can also be
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* used to boost the scores of matches on that token.
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* <li>Set it to values greater than one to inhibit exact phrase matches.
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* If, for example, one does not want phrases to match across removed stop
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* words, then one could build a stop word filter that removes stop words and
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* also sets the increment to the number of stop words removed before each
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* non-stop word. Then exact phrase queries will only match when the terms
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* occur with no intervening stop words.
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public class PositionIncrementAttributeImpl extends AttributeImpl implements PositionIncrementAttribute, Cloneable, Serializable {
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private int positionIncrement = 1;
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/** Set the position increment. The default value is one.
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* @param positionIncrement the distance from the prior term
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public void setPositionIncrement(int positionIncrement) {
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if (positionIncrement < 0)
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throw new IllegalArgumentException
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("Increment must be zero or greater: " + positionIncrement);
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this.positionIncrement = positionIncrement;
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/** Returns the position increment of this Token.
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* @see #setPositionIncrement
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public int getPositionIncrement() {
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return positionIncrement;
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this.positionIncrement = 1;
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public boolean equals(Object other) {
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if (other instanceof PositionIncrementAttributeImpl) {
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return positionIncrement == ((PositionIncrementAttributeImpl) other).positionIncrement;
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public int hashCode() {
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return positionIncrement;
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public void copyTo(AttributeImpl target) {
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PositionIncrementAttribute t = (PositionIncrementAttribute) target;
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t.setPositionIncrement(positionIncrement);