| package org.apache.lucene.util; |
| |
| /** |
| * 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. |
| */ |
| |
| /* Derived from org.apache.lucene.util.PriorityQueue of March 2005 */ |
| |
| import java.io.IOException; |
| |
| import org.apache.lucene.search.DocIdSetIterator; |
| import org.apache.lucene.search.Scorer; |
| |
| /** A ScorerDocQueue maintains a partial ordering of its Scorers such that the |
| least Scorer can always be found in constant time. Put()'s and pop()'s |
| require log(size) time. The ordering is by Scorer.doc(). |
| * |
| * @lucene.internal |
| */ |
| public class ScorerDocQueue { // later: SpansQueue for spans with doc and term positions |
| private final HeapedScorerDoc[] heap; |
| private final int maxSize; |
| private int size; |
| |
| private class HeapedScorerDoc { |
| Scorer scorer; |
| int doc; |
| |
| HeapedScorerDoc(Scorer s) { this(s, s.docID()); } |
| |
| HeapedScorerDoc(Scorer scorer, int doc) { |
| this.scorer = scorer; |
| this.doc = doc; |
| } |
| |
| void adjust() { doc = scorer.docID(); } |
| } |
| |
| private HeapedScorerDoc topHSD; // same as heap[1], only for speed |
| |
| /** Create a ScorerDocQueue with a maximum size. */ |
| public ScorerDocQueue(int maxSize) { |
| // assert maxSize >= 0; |
| size = 0; |
| int heapSize = maxSize + 1; |
| heap = new HeapedScorerDoc[heapSize]; |
| this.maxSize = maxSize; |
| topHSD = heap[1]; // initially null |
| } |
| |
| /** |
| * Adds a Scorer to a ScorerDocQueue in log(size) time. |
| * If one tries to add more Scorers than maxSize |
| * a RuntimeException (ArrayIndexOutOfBound) is thrown. |
| */ |
| public final void put(Scorer scorer) { |
| size++; |
| heap[size] = new HeapedScorerDoc(scorer); |
| upHeap(); |
| } |
| |
| /** |
| * Adds a Scorer to the ScorerDocQueue in log(size) time if either |
| * the ScorerDocQueue is not full, or not lessThan(scorer, top()). |
| * @param scorer |
| * @return true if scorer is added, false otherwise. |
| */ |
| public boolean insert(Scorer scorer){ |
| if (size < maxSize) { |
| put(scorer); |
| return true; |
| } else { |
| int docNr = scorer.docID(); |
| if ((size > 0) && (! (docNr < topHSD.doc))) { // heap[1] is top() |
| heap[1] = new HeapedScorerDoc(scorer, docNr); |
| downHeap(); |
| return true; |
| } else { |
| return false; |
| } |
| } |
| } |
| |
| /** Returns the least Scorer of the ScorerDocQueue in constant time. |
| * Should not be used when the queue is empty. |
| */ |
| public final Scorer top() { |
| // assert size > 0; |
| return topHSD.scorer; |
| } |
| |
| /** Returns document number of the least Scorer of the ScorerDocQueue |
| * in constant time. |
| * Should not be used when the queue is empty. |
| */ |
| public final int topDoc() { |
| // assert size > 0; |
| return topHSD.doc; |
| } |
| |
| public final float topScore() throws IOException { |
| // assert size > 0; |
| return topHSD.scorer.score(); |
| } |
| |
| public final boolean topNextAndAdjustElsePop() throws IOException { |
| return checkAdjustElsePop(topHSD.scorer.nextDoc() != DocIdSetIterator.NO_MORE_DOCS); |
| } |
| |
| public final boolean topSkipToAndAdjustElsePop(int target) throws IOException { |
| return checkAdjustElsePop(topHSD.scorer.advance(target) != DocIdSetIterator.NO_MORE_DOCS); |
| } |
| |
| private boolean checkAdjustElsePop(boolean cond) { |
| if (cond) { // see also adjustTop |
| topHSD.doc = topHSD.scorer.docID(); |
| } else { // see also popNoResult |
| heap[1] = heap[size]; // move last to first |
| heap[size] = null; |
| size--; |
| } |
| downHeap(); |
| return cond; |
| } |
| |
| /** Removes and returns the least scorer of the ScorerDocQueue in log(size) |
| * time. |
| * Should not be used when the queue is empty. |
| */ |
| public final Scorer pop() { |
| // assert size > 0; |
| Scorer result = topHSD.scorer; |
| popNoResult(); |
| return result; |
| } |
| |
| /** Removes the least scorer of the ScorerDocQueue in log(size) time. |
| * Should not be used when the queue is empty. |
| */ |
| private final void popNoResult() { |
| heap[1] = heap[size]; // move last to first |
| heap[size] = null; |
| size--; |
| downHeap(); // adjust heap |
| } |
| |
| /** Should be called when the scorer at top changes doc() value. |
| * Still log(n) worst case, but it's at least twice as fast to <pre> |
| * { pq.top().change(); pq.adjustTop(); } |
| * </pre> instead of <pre> |
| * { o = pq.pop(); o.change(); pq.push(o); } |
| * </pre> |
| */ |
| public final void adjustTop() { |
| // assert size > 0; |
| topHSD.adjust(); |
| downHeap(); |
| } |
| |
| /** Returns the number of scorers currently stored in the ScorerDocQueue. */ |
| public final int size() { |
| return size; |
| } |
| |
| /** Removes all entries from the ScorerDocQueue. */ |
| public final void clear() { |
| for (int i = 0; i <= size; i++) { |
| heap[i] = null; |
| } |
| size = 0; |
| } |
| |
| private final void upHeap() { |
| int i = size; |
| HeapedScorerDoc node = heap[i]; // save bottom node |
| int j = i >>> 1; |
| while ((j > 0) && (node.doc < heap[j].doc)) { |
| heap[i] = heap[j]; // shift parents down |
| i = j; |
| j = j >>> 1; |
| } |
| heap[i] = node; // install saved node |
| topHSD = heap[1]; |
| } |
| |
| private final void downHeap() { |
| int i = 1; |
| HeapedScorerDoc node = heap[i]; // save top node |
| int j = i << 1; // find smaller child |
| int k = j + 1; |
| if ((k <= size) && (heap[k].doc < heap[j].doc)) { |
| j = k; |
| } |
| while ((j <= size) && (heap[j].doc < node.doc)) { |
| heap[i] = heap[j]; // shift up child |
| i = j; |
| j = i << 1; |
| k = j + 1; |
| if (k <= size && (heap[k].doc < heap[j].doc)) { |
| j = k; |
| } |
| } |
| heap[i] = node; // install saved node |
| topHSD = heap[1]; |
| } |
| } |