/*
* Licensed to Elastic Search and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Elastic Search 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.elasticsearch.common.lucene.search;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermEnum;
import org.apache.lucene.search.MultiPhraseQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.util.ToStringUtils;
import java.io.IOException;
import java.util.*;
public class MultiPhrasePrefixQuery extends Query {
private String field;
private ArrayList<Term[]> termArrays = new ArrayList<Term[]>();
private ArrayList<Integer> positions = new ArrayList<Integer>();
private int maxExpansions = Integer.MAX_VALUE;
private int slop = 0;
/**
* Sets the phrase slop for this query.
*
* @see org.apache.lucene.search.PhraseQuery#setSlop(int)
*/
public void setSlop(int s) {
slop = s;
}
public void setMaxExpansions(int maxExpansions) {
this.maxExpansions = maxExpansions;
}
/**
* Sets the phrase slop for this query.
*
* @see org.apache.lucene.search.PhraseQuery#getSlop()
*/
public int getSlop() {
return slop;
}
/**
* Add a single term at the next position in the phrase.
*
* @see org.apache.lucene.search.PhraseQuery#add(Term)
*/
public void add(Term term) {
add(new Term[]{term});
}
/**
* Add multiple terms at the next position in the phrase. Any of the terms
* may match.
*
* @see org.apache.lucene.search.PhraseQuery#add(Term)
*/
public void add(Term[] terms) {
int position = 0;
if (positions.size() > 0)
position = positions.get(positions.size() - 1).intValue() + 1;
add(terms, position);
}
/**
* Allows to specify the relative position of terms within the phrase.
*
* @param terms
* @param position
* @see org.apache.lucene.search.PhraseQuery#add(Term, int)
*/
public void add(Term[] terms, int position) {
if (termArrays.size() == 0)
field = terms[0].field();
for (int i = 0; i < terms.length; i++) {
if (terms[i].field() != field) {
throw new IllegalArgumentException(
"All phrase terms must be in the same field (" + field + "): "
+ terms[i]);
}
}
termArrays.add(terms);
positions.add(Integer.valueOf(position));
}
/**
* Returns a List of the terms in the multiphrase.
* Do not modify the List or its contents.
*/
public List<Term[]> getTermArrays() {
return Collections.unmodifiableList(termArrays);
}
/**
* Returns the relative positions of terms in this phrase.
*/
public int[] getPositions() {
int[] result = new int[positions.size()];
for (int i = 0; i < positions.size(); i++)
result[i] = positions.get(i).intValue();
return result;
}
@Override public Query rewrite(IndexReader reader) throws IOException {
if (termArrays.isEmpty()) {
return MatchNoDocsQuery.INSTANCE;
}
MultiPhraseQuery query = new MultiPhraseQuery();
query.setSlop(slop);
int sizeMinus1 = termArrays.size() - 1;
for (int i = 0; i < sizeMinus1; i++) {
query.add(termArrays.get(i), positions.get(i));
}
Term[] suffixTerms = termArrays.get(sizeMinus1);
int position = positions.get(sizeMinus1);
List<Term> terms = new ArrayList<Term>();
for (Term term : suffixTerms) {
getPrefixTerms(terms, term, reader);
if (terms.size() > maxExpansions) {
break;
}
}
if (terms.isEmpty()) {
return MatchNoDocsQuery.INSTANCE;
}
query.add(terms.toArray(new Term[terms.size()]), position);
return query.rewrite(reader);
}
private void getPrefixTerms(List<Term> terms, final Term prefix, final IndexReader reader) throws IOException {
TermEnum enumerator = reader.terms(prefix);
try {
do {
Term term = enumerator.term();
if (term != null
&& term.text().startsWith(prefix.text())
&& term.field().equals(field)) {
terms.add(term);
} else {
break;
}
if (terms.size() >= maxExpansions) {
break;
}
} while (enumerator.next());
} finally {
enumerator.close();
}
}
@Override
public final String toString(String f) {
StringBuilder buffer = new StringBuilder();
if (field == null || !field.equals(f)) {
buffer.append(field);
buffer.append(":");
}
buffer.append("\"");
Iterator<Term[]> i = termArrays.iterator();
while (i.hasNext()) {
Term[] terms = i.next();
if (terms.length > 1) {
buffer.append("(");
for (int j = 0; j < terms.length; j++) {
buffer.append(terms[j].text());
if (j < terms.length - 1)
buffer.append(" ");
}
buffer.append(")");
} else {
buffer.append(terms[0].text());
}
if (i.hasNext())
buffer.append(" ");
}
buffer.append("\"");
if (slop != 0) {
buffer.append("~");
buffer.append(slop);
}
buffer.append(ToStringUtils.boost(getBoost()));
return buffer.toString();
}
/**
* Returns true if <code>o</code> is equal to this.
*/
@Override
public boolean equals(Object o) {
if (!(o instanceof MultiPhrasePrefixQuery)) return false;
MultiPhrasePrefixQuery other = (MultiPhrasePrefixQuery) o;
return this.getBoost() == other.getBoost()
&& this.slop == other.slop
&& termArraysEquals(this.termArrays, other.termArrays)
&& this.positions.equals(other.positions);
}
/**
* Returns a hash code value for this object.
*/
@Override
public int hashCode() {
return Float.floatToIntBits(getBoost())
^ slop
^ termArraysHashCode()
^ positions.hashCode()
^ 0x4AC65113;
}
// Breakout calculation of the termArrays hashcode
private int termArraysHashCode() {
int hashCode = 1;
for (final Term[] termArray : termArrays) {
hashCode = 31 * hashCode
+ (termArray == null ? 0 : Arrays.hashCode(termArray));
}
return hashCode;
}
// Breakout calculation of the termArrays equals
private boolean termArraysEquals(List<Term[]> termArrays1, List<Term[]> termArrays2) {
if (termArrays1.size() != termArrays2.size()) {
return false;
}
ListIterator<Term[]> iterator1 = termArrays1.listIterator();
ListIterator<Term[]> iterator2 = termArrays2.listIterator();
while (iterator1.hasNext()) {
Term[] termArray1 = iterator1.next();
Term[] termArray2 = iterator2.next();
if (!(termArray1 == null ? termArray2 == null : Arrays.equals(termArray1,
termArray2))) {
return false;
}
}
return true;
}
}