--- /dev/null
+package org.apache.lucene.search;
+
+/**
+ * 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.index.IndexReader;
+import org.apache.lucene.search.DocIdSet;
+import org.apache.lucene.search.DocIdSetIterator;
+import org.apache.lucene.search.Filter;
+import org.apache.lucene.util.OpenBitSet;
+import org.apache.lucene.util.OpenBitSetDISI;
+
+/**
+ * <p>
+ * Allows multiple {@link Filter}s to be chained.
+ * Logical operations such as <b>NOT</b> and <b>XOR</b>
+ * are applied between filters. One operation can be used
+ * for all filters, or a specific operation can be declared
+ * for each filter.
+ * </p>
+ * <p>
+ * Order in which filters are called depends on
+ * the position of the filter in the chain. It's probably
+ * more efficient to place the most restrictive filters
+ * /least computationally-intensive filters first.
+ * </p>
+ *
+ */
+public class ChainedFilter extends Filter
+{
+ public static final int OR = 0;
+ public static final int AND = 1;
+ public static final int ANDNOT = 2;
+ public static final int XOR = 3;
+ /**
+ * Logical operation when none is declared. Defaults to
+ * OR.
+ */
+ public static int DEFAULT = OR;
+
+ /** The filter chain */
+ private Filter[] chain = null;
+
+ private int[] logicArray;
+
+ private int logic = -1;
+
+ /**
+ * Ctor.
+ * @param chain The chain of filters
+ */
+ public ChainedFilter(Filter[] chain)
+ {
+ this.chain = chain;
+ }
+
+ /**
+ * Ctor.
+ * @param chain The chain of filters
+ * @param logicArray Logical operations to apply between filters
+ */
+ public ChainedFilter(Filter[] chain, int[] logicArray)
+ {
+ this.chain = chain;
+ this.logicArray = logicArray;
+ }
+
+ /**
+ * Ctor.
+ * @param chain The chain of filters
+ * @param logic Logical operation to apply to ALL filters
+ */
+ public ChainedFilter(Filter[] chain, int logic)
+ {
+ this.chain = chain;
+ this.logic = logic;
+ }
+
+ /**
+ * {@link Filter#getDocIdSet}.
+ */
+ @Override
+ public DocIdSet getDocIdSet(IndexReader reader) throws IOException
+ {
+ int[] index = new int[1]; // use array as reference to modifiable int;
+ index[0] = 0; // an object attribute would not be thread safe.
+ if (logic != -1)
+ return getDocIdSet(reader, logic, index);
+ else if (logicArray != null)
+ return getDocIdSet(reader, logicArray, index);
+ else
+ return getDocIdSet(reader, DEFAULT, index);
+ }
+
+ private DocIdSetIterator getDISI(Filter filter, IndexReader reader)
+ throws IOException {
+ DocIdSet docIdSet = filter.getDocIdSet(reader);
+ if (docIdSet == null) {
+ return DocIdSet.EMPTY_DOCIDSET.iterator();
+ } else {
+ DocIdSetIterator iter = docIdSet.iterator();
+ if (iter == null) {
+ return DocIdSet.EMPTY_DOCIDSET.iterator();
+ } else {
+ return iter;
+ }
+ }
+ }
+
+ private OpenBitSetDISI initialResult(IndexReader reader, int logic, int[] index)
+ throws IOException
+ {
+ OpenBitSetDISI result;
+ /**
+ * First AND operation takes place against a completely false
+ * bitset and will always return zero results.
+ */
+ if (logic == AND)
+ {
+ result = new OpenBitSetDISI(getDISI(chain[index[0]], reader), reader.maxDoc());
+ ++index[0];
+ }
+ else if (logic == ANDNOT)
+ {
+ result = new OpenBitSetDISI(getDISI(chain[index[0]], reader), reader.maxDoc());
+ result.flip(0,reader.maxDoc()); // NOTE: may set bits for deleted docs.
+ ++index[0];
+ }
+ else
+ {
+ result = new OpenBitSetDISI(reader.maxDoc());
+ }
+ return result;
+ }
+
+ /** Provide a SortedVIntList when it is definitely
+ * smaller than an OpenBitSet
+ * @deprecated Either use CachingWrapperFilter, or
+ * switch to a different DocIdSet implementation yourself.
+ * This method will be removed in Lucene 4.0
+ **/
+ @Deprecated
+ protected final DocIdSet finalResult(OpenBitSetDISI result, int maxDocs) {
+ return result;
+ }
+
+
+ /**
+ * Delegates to each filter in the chain.
+ * @param reader IndexReader
+ * @param logic Logical operation
+ * @return DocIdSet
+ */
+ private DocIdSet getDocIdSet(IndexReader reader, int logic, int[] index)
+ throws IOException
+ {
+ OpenBitSetDISI result = initialResult(reader, logic, index);
+ for (; index[0] < chain.length; index[0]++)
+ {
+ doChain(result, logic, chain[index[0]].getDocIdSet(reader));
+ }
+ return finalResult(result, reader.maxDoc());
+ }
+
+ /**
+ * Delegates to each filter in the chain.
+ * @param reader IndexReader
+ * @param logic Logical operation
+ * @return DocIdSet
+ */
+ private DocIdSet getDocIdSet(IndexReader reader, int[] logic, int[] index)
+ throws IOException
+ {
+ if (logic.length != chain.length)
+ throw new IllegalArgumentException("Invalid number of elements in logic array");
+
+ OpenBitSetDISI result = initialResult(reader, logic[0], index);
+ for (; index[0] < chain.length; index[0]++)
+ {
+ doChain(result, logic[index[0]], chain[index[0]].getDocIdSet(reader));
+ }
+ return finalResult(result, reader.maxDoc());
+ }
+
+ @Override
+ public String toString()
+ {
+ StringBuilder sb = new StringBuilder();
+ sb.append("ChainedFilter: [");
+ for (int i = 0; i < chain.length; i++)
+ {
+ sb.append(chain[i]);
+ sb.append(' ');
+ }
+ sb.append(']');
+ return sb.toString();
+ }
+
+ private void doChain(OpenBitSetDISI result, int logic, DocIdSet dis)
+ throws IOException {
+
+ if (dis instanceof OpenBitSet) {
+ // optimized case for OpenBitSets
+ switch (logic) {
+ case OR:
+ result.or((OpenBitSet) dis);
+ break;
+ case AND:
+ result.and((OpenBitSet) dis);
+ break;
+ case ANDNOT:
+ result.andNot((OpenBitSet) dis);
+ break;
+ case XOR:
+ result.xor((OpenBitSet) dis);
+ break;
+ default:
+ doChain(result, DEFAULT, dis);
+ break;
+ }
+ } else {
+ DocIdSetIterator disi;
+ if (dis == null) {
+ disi = DocIdSet.EMPTY_DOCIDSET.iterator();
+ } else {
+ disi = dis.iterator();
+ if (disi == null) {
+ disi = DocIdSet.EMPTY_DOCIDSET.iterator();
+ }
+ }
+
+ switch (logic) {
+ case OR:
+ result.inPlaceOr(disi);
+ break;
+ case AND:
+ result.inPlaceAnd(disi);
+ break;
+ case ANDNOT:
+ result.inPlaceNot(disi);
+ break;
+ case XOR:
+ result.inPlaceXor(disi);
+ break;
+ default:
+ doChain(result, DEFAULT, dis);
+ break;
+ }
+ }
+ }
+
+}
fnp / pylucene.git / blobdiff