Lucene example source code file (NoOutputs.java)

This example Lucene source code file (NoOutputs.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

dataoutput, no_output, no_output, nooutputs, nooutputs, object, object, outputs, override, override, string

The Lucene NoOutputs.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.store.DataInput;
import org.apache.lucene.store.DataOutput;

/**
 * Use this if you just want to build an FSA.
 *
 * @lucene.experimental
 */

public final class NoOutputs extends Outputs<Object> {

  static final Object NO_OUTPUT = new Object() {
    // NodeHash calls hashCode for this output; we fix this
    // so we get deterministic hashing.
    @Override
    public int hashCode() {
      return 42;
    }

    @Override
    public boolean equals(Object other) {
      return other == this;
    }
  };

  private static final NoOutputs singleton = new NoOutputs();

  private NoOutputs() {
  }

  public static NoOutputs getSingleton() {
    return singleton;
  }

  @Override
  public Object common(Object output1, Object output2) {
    assert output1 == NO_OUTPUT;
    assert output2 == NO_OUTPUT;
    return NO_OUTPUT;
  }

  @Override
  public Object subtract(Object output, Object inc) {
    assert output == NO_OUTPUT;
    assert inc == NO_OUTPUT;
    return NO_OUTPUT;
  }

  @Override
  public Object add(Object prefix, Object output) {
    assert prefix == NO_OUTPUT: "got " + prefix;
    assert output == NO_OUTPUT;
    return NO_OUTPUT;
  }

  @Override
  public void write(Object prefix, DataOutput out) {
    //assert false;
  }

  @Override
  public Object read(DataInput in) {
    //assert false;
    //return null;
    return NO_OUTPUT;
  }

  @Override
  public Object getNoOutput() {
    return NO_OUTPUT;
  }

  @Override
  public String outputToString(Object output) {
    return "";
  }
}