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.Collection;
import java.util.Set;
import java.util.ArrayList;
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 near the beginning of a field. */
public class SpanFirstQuery extends SpanQuery implements Cloneable {
private SpanQuery match;
private int end;
/** Construct a SpanFirstQuery matching spans in <code>match</code> whose end
* position is less than or equal to <code>end</code>. */
public SpanFirstQuery(SpanQuery match, int end) {
this.match = match;
this.end = end;
}
/** Return the SpanQuery whose matches are filtered. */
public SpanQuery getMatch() { return match; }
/** Return the maximum end position permitted in a match. */
public int getEnd() { return end; }
@Override
public String getField() { return match.getField(); }
@Override
public String toString(String field) {
StringBuilder buffer = new StringBuilder();
buffer.append("spanFirst(");
buffer.append(match.toString(field));
buffer.append(", ");
buffer.append(end);
buffer.append(")");
buffer.append(ToStringUtils.boost(getBoost()));
return buffer.toString();
}
@Override
public Object clone() {
SpanFirstQuery spanFirstQuery = new SpanFirstQuery((SpanQuery) match.clone(), end);
spanFirstQuery.setBoost(getBoost());
return spanFirstQuery;
}
@Override
public void extractTerms(Set<Term> terms) {
match.extractTerms(terms);
}
@Override
public Spans getSpans(final IndexReader reader) throws IOException {
return new Spans() {
private Spans spans = match.getSpans(reader);
@Override
public boolean next() throws IOException {
while (spans.next()) { // scan to next match
if (end() <= end)
return true;
}
return false;
}
@Override
public boolean skipTo(int target) throws IOException {
if (!spans.skipTo(target))
return false;
return spans.end() <= end || next();
}
@Override
public int doc() { return spans.doc(); }
@Override
public int start() { return spans.start(); }
@Override
public int end() { return spans.end(); }
// TODO: Remove warning after API has been finalized
@Override
public Collection<byte[]> getPayload() throws IOException {
ArrayList<byte[]> result = null;
if (spans.isPayloadAvailable()) {
result = new ArrayList<byte[]>(spans.getPayload());
}
return result;//TODO: any way to avoid the new construction?
}
// TODO: Remove warning after API has been finalized
@Override
public boolean isPayloadAvailable() {
return spans.isPayloadAvailable();
}
@Override
public String toString() {
return "spans(" + SpanFirstQuery.this.toString() + ")";
}
};
}
@Override
public Query rewrite(IndexReader reader) throws IOException {
SpanFirstQuery clone = null;
SpanQuery rewritten = (SpanQuery) match.rewrite(reader);
if (rewritten != match) {
clone = (SpanFirstQuery) this.clone();
clone.match = rewritten;
}
if (clone != null) {
return clone; // some clauses rewrote
} else {
return this; // no clauses rewrote
}
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof SpanFirstQuery)) return false;
SpanFirstQuery other = (SpanFirstQuery)o;
return this.end == other.end
&& this.match.equals(other.match)
&& this.getBoost() == other.getBoost();
}
@Override
public int hashCode() {
int h = match.hashCode();
h ^= (h << 8) | (h >>> 25); // reversible
h ^= Float.floatToRawIntBits(getBoost()) ^ end;
return h;
}
}