| 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; |
| |
| /** |
| * Output is a long, for each input term. NOTE: the |
| * resulting FST is not guaranteed to be minimal! See |
| * {@link Builder}. You cannot store 0 output with this |
| * (that's reserved to mean "no output")! |
| * |
| * @lucene.experimental |
| */ |
| |
| public final class PositiveIntOutputs extends Outputs<Long> { |
| |
| private final static Long NO_OUTPUT = new Long(0); |
| |
| private final boolean doShare; |
| |
| private final static PositiveIntOutputs singletonShare = new PositiveIntOutputs(true); |
| private final static PositiveIntOutputs singletonNoShare = new PositiveIntOutputs(false); |
| |
| private PositiveIntOutputs(boolean doShare) { |
| this.doShare = doShare; |
| } |
| |
| public static PositiveIntOutputs getSingleton(boolean doShare) { |
| return doShare ? singletonShare : singletonNoShare; |
| } |
| |
| public Long get(long v) { |
| if (v == 0) { |
| return NO_OUTPUT; |
| } else { |
| return Long.valueOf(v); |
| } |
| } |
| |
| @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 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(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 instanceof Long; |
| assert o == NO_OUTPUT || o > 0; |
| return true; |
| } |
| |
| @Override |
| public Long getNoOutput() { |
| return NO_OUTPUT; |
| } |
| |
| @Override |
| public String outputToString(Long output) { |
| return output.toString(); |
| } |
| } |