package org.apache.lucene.index;/** * 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;/** * TermPositions provides an interface for enumerating the &lt;document, * frequency, &lt;position&gt;* &gt; tuples for a term.  <p> The document and * frequency are the same as for a TermDocs.  The positions portion lists the ordinal * positions of each occurrence of a term in a document. * * @see IndexReader#termPositions() */public interface TermPositions    extends TermDocs{    /** Returns next position in the current document.  It is an error to call    this more than {@link #freq()} times    without calling {@link #next()}<p> This is    invalid until {@link #next()} is called for    the first time.    */    int nextPosition() throws IOException;        /**      * Returns the length of the payload at the current term position.     * This is invalid until {@link #nextPosition()} is called for     * the first time.<br>     * @return length of the current payload in number of bytes     */    int getPayloadLength();        /**      * Returns the payload data at the current term position.     * This is invalid until {@link #nextPosition()} is called for     * the first time.     * This method must not be called more than once after each call     * of {@link #nextPosition()}. However, payloads are loaded lazily,     * so if the payload data for the current position is not needed,     * this method may not be called at all for performance reasons.<br>     *      * @param data the array into which the data of this payload is to be     *             stored, if it is big enough; otherwise, a new byte[] array     *             is allocated for this purpose.      * @param offset the offset in the array into which the data of this payload     *               is to be stored.     * @return a byte[] array containing the data of this payload     * @throws IOException     */    byte[] getPayload(byte[] data, int offset) throws IOException;  /**   * Checks if a payload can be loaded at this position.   * <p>   * Payloads can only be loaded once per call to    * {@link #nextPosition()}.   *    * @return true if there is a payload available at this position that can be loaded   */    public boolean isPayloadAvailable();}