| /* |
| * 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 org.apache.lucene.store.DataInput; |
| import org.apache.lucene.store.DataOutput; |
| |
| /** |
| * A null FST {@link Outputs} implementation; 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 Object merge(Object first, Object second) { |
| assert first == NO_OUTPUT; |
| assert second == 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 ""; |
| } |
| |
| @Override |
| public long ramBytesUsed(Object output) { |
| return 0; |
| } |
| |
| @Override |
| public String toString() { |
| return "NoOutputs"; |
| } |
| } |