/*
 * 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.
 */
package org.apache.lucene.util.fst;


import java.io.IOException;

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

An FST Outputs implementation, holding two other outputs.
@lucene.experimental
/** * An FST {@link Outputs} implementation, holding two other outputs. * * @lucene.experimental */
public class PairOutputs<A,B> extends Outputs<PairOutputs.Pair<A,B>> { private final Pair<A,B> NO_OUTPUT; private final Outputs<A> outputs1; private final Outputs<B> outputs2;
Holds a single pair of two outputs.
/** Holds a single pair of two outputs. */
public static class Pair<A,B> { public final A output1; public final B output2; // use newPair private Pair(A output1, B output2) { this.output1 = output1; this.output2 = output2; } @Override @SuppressWarnings("rawtypes") public boolean equals(Object other) { if (other == this) { return true; } else if (other instanceof Pair) { Pair pair = (Pair) other; return output1.equals(pair.output1) && output2.equals(pair.output2); } else { return false; } } @Override public int hashCode() { return output1.hashCode() + output2.hashCode(); } @Override public String toString() { return "Pair(" + output1 + "," + output2 + ")"; } }; public PairOutputs(Outputs<A> outputs1, Outputs<B> outputs2) { this.outputs1 = outputs1; this.outputs2 = outputs2; NO_OUTPUT = new Pair<>(outputs1.getNoOutput(), outputs2.getNoOutput()); }
Create a new Pair
/** Create a new Pair */
public Pair<A,B> newPair(A a, B b) { if (a.equals(outputs1.getNoOutput())) { a = outputs1.getNoOutput(); } if (b.equals(outputs2.getNoOutput())) { b = outputs2.getNoOutput(); } if (a == outputs1.getNoOutput() && b == outputs2.getNoOutput()) { return NO_OUTPUT; } else { final Pair<A,B> p = new Pair<>(a, b); assert valid(p); return p; } } // for assert private boolean valid(Pair<A,B> pair) { final boolean noOutput1 = pair.output1.equals(outputs1.getNoOutput()); final boolean noOutput2 = pair.output2.equals(outputs2.getNoOutput()); if (noOutput1 && pair.output1 != outputs1.getNoOutput()) { return false; } if (noOutput2 && pair.output2 != outputs2.getNoOutput()) { return false; } if (noOutput1 && noOutput2) { if (pair != NO_OUTPUT) { return false; } else { return true; } } else { return true; } } @Override public Pair<A,B> common(Pair<A,B> pair1, Pair<A,B> pair2) { assert valid(pair1); assert valid(pair2); return newPair(outputs1.common(pair1.output1, pair2.output1), outputs2.common(pair1.output2, pair2.output2)); } @Override public Pair<A,B> subtract(Pair<A,B> output, Pair<A,B> inc) { assert valid(output); assert valid(inc); return newPair(outputs1.subtract(output.output1, inc.output1), outputs2.subtract(output.output2, inc.output2)); } @Override public Pair<A,B> add(Pair<A,B> prefix, Pair<A,B> output) { assert valid(prefix); assert valid(output); return newPair(outputs1.add(prefix.output1, output.output1), outputs2.add(prefix.output2, output.output2)); } @Override public void write(Pair<A,B> output, DataOutput writer) throws IOException { assert valid(output); outputs1.write(output.output1, writer); outputs2.write(output.output2, writer); } @Override public Pair<A,B> read(DataInput in) throws IOException { A output1 = outputs1.read(in); B output2 = outputs2.read(in); return newPair(output1, output2); } @Override public void skipOutput(DataInput in) throws IOException { outputs1.skipOutput(in); outputs2.skipOutput(in); } @Override public Pair<A,B> getNoOutput() { return NO_OUTPUT; } @Override public String outputToString(Pair<A,B> output) { assert valid(output); return "<pair:" + outputs1.outputToString(output.output1) + "," + outputs2.outputToString(output.output2) + ">"; } @Override public String toString() { return "PairOutputs<" + outputs1 + "," + outputs2 + ">"; } private static final long BASE_NUM_BYTES = RamUsageEstimator.shallowSizeOf(new Pair<Object,Object>(null, null)); @Override public long ramBytesUsed(Pair<A,B> output) { long ramBytesUsed = BASE_NUM_BYTES; if (output.output1 != null) { ramBytesUsed += outputs1.ramBytesUsed(output.output1); } if (output.output2 != null) { ramBytesUsed += outputs2.ramBytesUsed(output.output2); } return ramBytesUsed; } }