package org.apache.lucene.search.spans;
/**
* Copyright 2004 The Apache Software Foundation
*
* Licensed 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 org.apache.lucene.index.IndexReader;
/** Matches spans near the beginning of a field. */
public class SpanFirstQuery extends SpanQuery {
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; }
public String getField() { return match.getField(); }
public Collection getTerms() { return match.getTerms(); }
public String toString(String field) {
StringBuffer buffer = new StringBuffer();
buffer.append("spanFirst(");
buffer.append(match.toString(field));
buffer.append(", ");
buffer.append(end);
buffer.append(")");
return buffer.toString();
}
public Spans getSpans(final IndexReader reader) throws IOException {
return new Spans() {
private Spans spans = match.getSpans(reader);
public boolean next() throws IOException {
while (spans.next()) { // scan to next match
if (end() <= end)
return true;
}
return false;
}
public boolean skipTo(int target) throws IOException {
if (!spans.skipTo(target))
return false;
if (spans.end() <= end) // there is a match
return true;
return next(); // scan to next match
}
public int doc() { return spans.doc(); }
public int start() { return spans.start(); }
public int end() { return spans.end(); }
public String toString() {
return "spans(" + SpanFirstQuery.this.toString() + ")";
}
};
}
}
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