/*
 * 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;
import org.apache.lucene.util.SuppressForbidden;

An FST Outputs implementation where each output is a non-negative long value.
@lucene.experimental
/** * An FST {@link Outputs} implementation where each output * is a non-negative long value. * * @lucene.experimental */
@SuppressForbidden(reason = "Uses a Long instance as a marker") public final class PositiveIntOutputs extends Outputs<Long> { private final static Long NO_OUTPUT = new Long(0); private final static PositiveIntOutputs singleton = new PositiveIntOutputs(); private PositiveIntOutputs() { } public static PositiveIntOutputs getSingleton() { return singleton; } @Override public Long common(Long output1, Long output2) { assert valid(output1); assert valid(output2); if (output1 == NO_OUTPUT || output2 == NO_OUTPUT) { return NO_OUTPUT; } else { assert output1 > 0; assert output2 > 0; return Math.min(output1, output2); } } @Override public Long subtract(Long output, Long inc) { assert valid(output); assert valid(inc); assert output >= inc; if (inc == NO_OUTPUT) { return output; } else if (output.equals(inc)) { return NO_OUTPUT; } else { return output - inc; } } @Override public Long add(Long prefix, Long output) { assert valid(prefix); assert valid(output); if (prefix == NO_OUTPUT) { return output; } else if (output == NO_OUTPUT) { return prefix; } else { return prefix + output; } } @Override public void write(Long output, DataOutput out) throws IOException { assert valid(output); out.writeVLong(output); } @Override public Long read(DataInput in) throws IOException { long v = in.readVLong(); if (v == 0) { return NO_OUTPUT; } else { return v; } } private boolean valid(Long o) { assert o != null; assert o == NO_OUTPUT || o > 0: "o=" + o; return true; } @Override public Long getNoOutput() { return NO_OUTPUT; } @Override public String outputToString(Long output) { return output.toString(); } @Override public String toString() { return "PositiveIntOutputs"; } @Override public long ramBytesUsed(Long output) { return RamUsageEstimator.sizeOf(output); } }