package org.apache.lucene.search.spans;
/**
* 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.util.List;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Set;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.Query;
import org.apache.lucene.util.ToStringUtils;
/** Matches spans which are near one another. One can specify <i>slop</i>, the
* maximum number of intervening unmatched positions, as well as whether
* matches are required to be in-order. */
public class SpanNearQuery extends SpanQuery implements Cloneable {
protected List<SpanQuery> clauses;
protected int slop;
protected boolean inOrder;
protected String field;
private boolean collectPayloads;
/** Construct a SpanNearQuery. Matches spans matching a span from each
* clause, with up to <code>slop</code> total unmatched positions between
* them. * When <code>inOrder</code> is true, the spans from each clause
* must be * ordered as in <code>clauses</code>. */
public SpanNearQuery(SpanQuery[] clauses, int slop, boolean inOrder) {
this(clauses, slop, inOrder, true);
}
public SpanNearQuery(SpanQuery[] clauses, int slop, boolean inOrder, boolean collectPayloads) {
// copy clauses array into an ArrayList
this.clauses = new ArrayList<SpanQuery>(clauses.length);
for (int i = 0; i < clauses.length; i++) {
SpanQuery clause = clauses[i];
if (i == 0) { // check field
field = clause.getField();
} else if (!clause.getField().equals(field)) {
throw new IllegalArgumentException("Clauses must have same field.");
}
this.clauses.add(clause);
}
this.collectPayloads = collectPayloads;
this.slop = slop;
this.inOrder = inOrder;
}
/** Return the clauses whose spans are matched. */
public SpanQuery[] getClauses() {
return clauses.toArray(new SpanQuery[clauses.size()]);
}
/** Return the maximum number of intervening unmatched positions permitted.*/
public int getSlop() { return slop; }
/** Return true if matches are required to be in-order.*/
public boolean isInOrder() { return inOrder; }
@Override
public String getField() { return field; }
@Override
public void extractTerms(Set<Term> terms) {
for (final SpanQuery clause : clauses) {
clause.extractTerms(terms);
}
}
@Override
public String toString(String field) {
StringBuilder buffer = new StringBuilder();
buffer.append("spanNear([");
Iterator<SpanQuery> i = clauses.iterator();
while (i.hasNext()) {
SpanQuery clause = i.next();
buffer.append(clause.toString(field));
if (i.hasNext()) {
buffer.append(", ");
}
}
buffer.append("], ");
buffer.append(slop);
buffer.append(", ");
buffer.append(inOrder);
buffer.append(")");
buffer.append(ToStringUtils.boost(getBoost()));
return buffer.toString();
}
@Override
public Spans getSpans(final IndexReader reader) throws IOException {
if (clauses.size() == 0) // optimize 0-clause case
return new SpanOrQuery(getClauses()).getSpans(reader);
if (clauses.size() == 1) // optimize 1-clause case
return clauses.get(0).getSpans(reader);
return inOrder
? (Spans) new NearSpansOrdered(this, reader, collectPayloads)
: (Spans) new NearSpansUnordered(this, reader);
}
@Override
public Query rewrite(IndexReader reader) throws IOException {
SpanNearQuery clone = null;
for (int i = 0 ; i < clauses.size(); i++) {
SpanQuery c = clauses.get(i);
SpanQuery query = (SpanQuery) c.rewrite(reader);
if (query != c) { // clause rewrote: must clone
if (clone == null)
clone = (SpanNearQuery) this.clone();
clone.clauses.set(i,query);
}
}
if (clone != null) {
return clone; // some clauses rewrote
} else {
return this; // no clauses rewrote
}
}
@Override
public Object clone() {
int sz = clauses.size();
SpanQuery[] newClauses = new SpanQuery[sz];
for (int i = 0; i < sz; i++) {
newClauses[i] = (SpanQuery) clauses.get(i).clone();
}
SpanNearQuery spanNearQuery = new SpanNearQuery(newClauses, slop, inOrder);
spanNearQuery.setBoost(getBoost());
return spanNearQuery;
}
/** Returns true iff <code>o</code> is equal to this. */
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof SpanNearQuery)) return false;
final SpanNearQuery spanNearQuery = (SpanNearQuery) o;
if (inOrder != spanNearQuery.inOrder) return false;
if (slop != spanNearQuery.slop) return false;
if (!clauses.equals(spanNearQuery.clauses)) return false;
return getBoost() == spanNearQuery.getBoost();
}
@Override
public int hashCode() {
int result;
result = clauses.hashCode();
// Mix bits before folding in things like boost, since it could cancel the
// last element of clauses. This particular mix also serves to
// differentiate SpanNearQuery hashcodes from others.
result ^= (result << 14) | (result >>> 19); // reversible
result += Float.floatToRawIntBits(getBoost());
result += slop;
result ^= (inOrder ? 0x99AFD3BD : 0);
return result;
}
}