| /* |
| * 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.index; |
| |
| import java.io.IOException; |
| import org.apache.lucene.util.AttributeSource; |
| import org.apache.lucene.util.BytesRef; |
| |
| /** |
| * A base TermsEnum that adds default implementations for |
| * |
| * <ul> |
| * <li>{@link #attributes()} |
| * <li>{@link #termState()} |
| * <li>{@link #seekExact(BytesRef)} |
| * <li>{@link #seekExact(BytesRef, TermState)} |
| * </ul> |
| * |
| * In some cases, the default implementation may be slow and consume huge memory, so subclass SHOULD |
| * have its own implementation if possible. |
| */ |
| public abstract class BaseTermsEnum extends TermsEnum { |
| |
| private AttributeSource atts = null; |
| |
| /** Sole constructor. (For invocation by subclass constructors, typically implicit.) */ |
| protected BaseTermsEnum() { |
| super(); |
| } |
| |
| @Override |
| public TermState termState() throws IOException { |
| return new TermState() { |
| @Override |
| public void copyFrom(TermState other) { |
| throw new UnsupportedOperationException(); |
| } |
| }; |
| } |
| |
| @Override |
| public boolean seekExact(BytesRef text) throws IOException { |
| return seekCeil(text) == SeekStatus.FOUND; |
| } |
| |
| @Override |
| public void seekExact(BytesRef term, TermState state) throws IOException { |
| if (!seekExact(term)) { |
| throw new IllegalArgumentException("term=" + term + " does not exist"); |
| } |
| } |
| |
| public AttributeSource attributes() { |
| if (atts == null) { |
| atts = new AttributeSource(); |
| } |
| return atts; |
| } |
| } |