| /* |
| * 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.search.join; |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.index.FilteredTermsEnum; |
| import org.apache.lucene.index.TermsEnum; |
| import org.apache.lucene.util.BytesRef; |
| import org.apache.lucene.util.BytesRefHash; |
| |
| /** |
| * A filtered TermsEnum that uses a BytesRefHash as a filter |
| * @lucene.internal |
| */ |
| public class SeekingTermSetTermsEnum extends FilteredTermsEnum { |
| |
| private final BytesRefHash terms; |
| private final int[] ords; |
| private final int lastElement; |
| |
| private final BytesRef lastTerm; |
| private final BytesRef spare = new BytesRef(); |
| |
| private BytesRef seekTerm; |
| private int upto = 0; |
| |
| /** |
| * Constructor |
| */ |
| public SeekingTermSetTermsEnum(TermsEnum tenum, BytesRefHash terms, int[] ords) { |
| super(tenum); |
| this.terms = terms; |
| this.ords = ords; |
| lastElement = terms.size() - 1; |
| lastTerm = terms.get(ords[lastElement], new BytesRef()); |
| seekTerm = terms.get(ords[upto], spare); |
| } |
| |
| @Override |
| protected BytesRef nextSeekTerm(BytesRef currentTerm) throws IOException { |
| BytesRef temp = seekTerm; |
| seekTerm = null; |
| return temp; |
| } |
| |
| @Override |
| protected AcceptStatus accept(BytesRef term) throws IOException { |
| if (term.compareTo(lastTerm) > 0) { |
| return AcceptStatus.END; |
| } |
| |
| BytesRef currentTerm = terms.get(ords[upto], spare); |
| if (term.compareTo(currentTerm) == 0) { |
| if (upto == lastElement) { |
| return AcceptStatus.YES; |
| } else { |
| seekTerm = terms.get(ords[++upto], spare); |
| return AcceptStatus.YES_AND_SEEK; |
| } |
| } else { |
| if (upto == lastElement) { |
| return AcceptStatus.NO; |
| } else { // Our current term doesn't match the the given term. |
| int cmp; |
| do { // We maybe are behind the given term by more than one step. Keep incrementing till we're the same or higher. |
| if (upto == lastElement) { |
| return AcceptStatus.NO; |
| } |
| // typically the terms dict is a superset of query's terms so it's unusual that we have to skip many of |
| // our terms so we don't do a binary search here |
| seekTerm = terms.get(ords[++upto], spare); |
| } while ((cmp = seekTerm.compareTo(term)) < 0); |
| if (cmp == 0) { |
| if (upto == lastElement) { |
| return AcceptStatus.YES; |
| } |
| seekTerm = terms.get(ords[++upto], spare); |
| return AcceptStatus.YES_AND_SEEK; |
| } else { |
| return AcceptStatus.NO_AND_SEEK; |
| } |
| } |
| } |
| } |
| |
| } |