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;
/** Expert: an enumeration of span matches. Used to implement span searching.
* Each span represents a range of term positions within a document. Matches
* are enumerated in order, by increasing document number, within that by
* increasing start position and finally by increasing end position. */
public interface Spans {
/** Move to the next match, returning true iff any such exists. */
boolean next() throws IOException;
/** Skips to the first match beyond the current, whose document number is
* greater than or equal to <i>target</i>. <p>Returns true iff there is such
* a match. <p>Behaves as if written: <pre>
* boolean skipTo(int target) {
* do {
* if (!next())
* return false;
* } while (target > doc());
* return true;
* }
* </pre>
* Most implementations are considerably more efficient than that.
*/
boolean skipTo(int target) throws IOException;
/** Returns the document number of the current match. Initially invalid. */
int doc();
/** Returns the start position of the current match. Initially invalid. */
int start();
/** Returns the end position of the current match. Initially invalid. */
int end();
}
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