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Lucene example source code file (IntsRefFSTEnum.java)

This example Lucene source code file (IntsRefFSTEnum.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

fstenum, inputoutput, inputoutput, intsref, intsref, intsreffstenum, io, ioexception, ioexception, override, override, t

The Lucene IntsRefFSTEnum.java source code

package org.apache.lucene.util.fst;

/**
 * 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 org.apache.lucene.util.IntsRef;

import java.io.IOException;

/** Can next() and advance() through the terms in an FST
 *
  * @lucene.experimental
*/

public final class IntsRefFSTEnum<T> extends FSTEnum {
  private final IntsRef current = new IntsRef(10);
  private final InputOutput<T> result = new InputOutput();
  private IntsRef target;

  public static class InputOutput<T> {
    public IntsRef input;
    public T output;
  }

  /** doFloor controls the behavior of advance: if it's true
   *  doFloor is true, advance positions to the biggest
   *  term before target.  */
  public IntsRefFSTEnum(FST<T> fst) {
    super(fst);
    result.input = current;
    current.offset = 1;
  }

  public InputOutput<T> current() {
    return result;
  }

  public InputOutput<T> next() throws IOException {
    //System.out.println("  enum.next");
    doNext();
    return setResult();
  }

  /** Seeks to smallest term that's >= target. */
  public InputOutput<T> seekCeil(IntsRef target) throws IOException {
    this.target = target;
    targetLength = target.length;
    super.doSeekCeil();
    return setResult();
  }

  /** Seeks to biggest term that's <= target. */
  public InputOutput<T> seekFloor(IntsRef target) throws IOException {
    this.target = target;
    targetLength = target.length;
    super.doSeekFloor();
    return setResult();
  }

  @Override
  protected int getTargetLabel() {
    if (upto-1 == target.length) {
      return FST.END_LABEL;
    } else {
      return target.ints[target.offset + upto - 1];
    }
  }

  @Override
  protected int getCurrentLabel() {
    // current.offset fixed at 1
    return current.ints[upto];
  }

  @Override
  protected void setCurrentLabel(int label) {
    current.ints[upto] = label;
  }

  @Override
  protected void grow() {
    current.grow(upto+1);
  }

  private InputOutput<T> setResult() {
    if (upto == 0) {
      return null;
    } else {
      current.length = upto-1;
      result.output = output[upto];
      return result;
    }
  }
}

Other Lucene examples (source code examples)

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