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Lucene example source code file (UpToTwoPositiveIntOutputs.java)

This example Lucene source code file (UpToTwoPositiveIntOutputs.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, io, ioexception, long, long, no_output, no_output, object, outputs, override, override, string, twolongs, twolongs, uptotwopositiveintoutputs

The Lucene UpToTwoPositiveIntOutputs.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 java.io.IOException;

import org.apache.lucene.store.DataInput;
import org.apache.lucene.store.DataOutput;

/**
 * Holds one or two longs for each input term.  If it's a
 * single output, Long is returned; else, TwoLongs.  Order
 * is preseved in the TwoLongs case, ie .first is the first
 * input/output added to Builder, and .second is the
 * second.  You cannot store 0 output with this (that's
 * reserved to mean "no output")!
 *
 * NOTE: the resulting FST is not guaranteed to be minimal!
 * See {@link Builder}.
 *
 * @lucene.experimental
 */

public final class UpToTwoPositiveIntOutputs extends Outputs<Object> {

  public final static class TwoLongs {
    final long first;
    final long second;

    public TwoLongs(long first, long second) {
      this.first = first;
      this.second = second;
      assert first >= 0;
      assert second >= 0;
    }

    @Override
    public String toString() {
      return "TwoLongs:" + first + "," + second;
    }

    @Override
    public boolean equals(Object _other) {
      if (_other instanceof TwoLongs) {
        final TwoLongs other = (TwoLongs) _other;
        return first == other.first && second == other.second;
      } else {
        return false;
      }
    }

    @Override
    public int hashCode() {
      return (int) ((first^(first>>>32)) ^ (second^(second>>32)));
    }
  }
  
  private final static Long NO_OUTPUT = new Long(0);

  private final boolean doShare;

  private final static UpToTwoPositiveIntOutputs singletonShare = new UpToTwoPositiveIntOutputs(true);
  private final static UpToTwoPositiveIntOutputs singletonNoShare = new UpToTwoPositiveIntOutputs(false);

  private UpToTwoPositiveIntOutputs(boolean doShare) {
    this.doShare = doShare;
  }

  public static UpToTwoPositiveIntOutputs getSingleton(boolean doShare) {
    return doShare ? singletonShare : singletonNoShare;
  }

  public Long get(long v) {
    if (v == 0) {
      return NO_OUTPUT;
    } else {
      return Long.valueOf(v);
    }
  }

  public TwoLongs get(long first, long second) {
    return new TwoLongs(first, second);
  }

  @Override
  public Long common(Object _output1, Object _output2) {
    assert valid(_output1, false);
    assert valid(_output2, false);
    final Long output1 = (Long) _output1;
    final Long output2 = (Long) _output2;
    if (output1 == NO_OUTPUT || output2 == NO_OUTPUT) {
      return NO_OUTPUT;
    } else if (doShare) {
      assert output1 > 0;
      assert output2 > 0;
      return Math.min(output1, output2);
    } else if (output1.equals(output2)) {
      return output1;
    } else {
      return NO_OUTPUT;
    }
  }

  @Override
  public Long subtract(Object _output, Object _inc) {
    assert valid(_output, false);
    assert valid(_inc, false);
    final Long output = (Long) _output;
    final Long inc = (Long) _inc;
    assert output >= inc;

    if (inc == NO_OUTPUT) {
      return output;
    } else if (output.equals(inc)) {
      return NO_OUTPUT;
    } else {
      return output - inc;
    }
  }

  @Override
  public Object add(Object _prefix, Object _output) {
    assert valid(_prefix, false);
    assert valid(_output, true);
    final Long prefix = (Long) _prefix;
    if (_output instanceof Long) {
      final Long output = (Long) _output;
      if (prefix == NO_OUTPUT) {
        return output;
      } else if (output == NO_OUTPUT) {
        return prefix;
      } else {
        return prefix + output;
      }
    } else {
      final TwoLongs output = (TwoLongs) _output;
      final long v = prefix;
      return new TwoLongs(output.first + v, output.second + v);
    }
  }

  @Override
  public void write(Object _output, DataOutput out) throws IOException {
    assert valid(_output, true);
    if (_output instanceof Long) {
      final Long output = (Long) _output;
      out.writeVLong(output<<1);
    } else {
      final TwoLongs output = (TwoLongs) _output;
      out.writeVLong((output.first<<1) | 1);
      out.writeVLong(output.second);
    }
  }

  @Override
  public Object read(DataInput in) throws IOException {
    final long code = in.readVLong();
    if ((code & 1) == 0) {
      // single long
      final long v = code >>> 1;
      if (v == 0) {
        return NO_OUTPUT;
      } else {
        return Long.valueOf(v);
      }
    } else {
      // two longs
      final long first = code >>> 1;
      final long second = in.readVLong();
      return new TwoLongs(first, second);
    }
  }

  private boolean valid(Long o) {
    assert o != null;
    assert o instanceof Long;
    assert o == NO_OUTPUT || o > 0;
    return true;
  }

  // Used only by assert
  private boolean valid(Object _o, boolean allowDouble) {
    if (!allowDouble) {
      assert _o instanceof Long;
      return valid((Long) _o);
    } else if (_o instanceof TwoLongs) {
      return true;
    } else {
      return valid((Long) _o);
    }
  }

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

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

  @Override
  public Object merge(Object first, Object second) {
    assert valid(first, false);
    assert valid(second, false);
    return new TwoLongs((Long) first, (Long) second);
  }
}

Other Lucene examples (source code examples)

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