--- /dev/null
+package org.apache.lucene.search.spans;
+
+/**
+ * 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 org.apache.lucene.index.IndexReader;
+import org.apache.lucene.util.ArrayUtil;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Collection;
+import java.util.Set;
+
+/** A Spans that is formed from the ordered subspans of a SpanNearQuery
+ * where the subspans do not overlap and have a maximum slop between them.
+ * <p>
+ * The formed spans only contains minimum slop matches.<br>
+ * The matching slop is computed from the distance(s) between
+ * the non overlapping matching Spans.<br>
+ * Successive matches are always formed from the successive Spans
+ * of the SpanNearQuery.
+ * <p>
+ * The formed spans may contain overlaps when the slop is at least 1.
+ * For example, when querying using
+ * <pre>t1 t2 t3</pre>
+ * with slop at least 1, the fragment:
+ * <pre>t1 t2 t1 t3 t2 t3</pre>
+ * matches twice:
+ * <pre>t1 t2 .. t3 </pre>
+ * <pre> t1 .. t2 t3</pre>
+ *
+ *
+ * Expert:
+ * Only public for subclassing. Most implementations should not need this class
+ */
+public class NearSpansOrdered extends Spans {
+ private final int allowedSlop;
+ private boolean firstTime = true;
+ private boolean more = false;
+
+ /** The spans in the same order as the SpanNearQuery */
+ private final Spans[] subSpans;
+
+ /** Indicates that all subSpans have same doc() */
+ private boolean inSameDoc = false;
+
+ private int matchDoc = -1;
+ private int matchStart = -1;
+ private int matchEnd = -1;
+ private List<byte[]> matchPayload;
+
+ private final Spans[] subSpansByDoc;
+ private final Comparator<Spans> spanDocComparator = new Comparator<Spans>() {
+ public int compare(Spans o1, Spans o2) {
+ return o1.doc() - o2.doc();
+ }
+ };
+
+ private SpanNearQuery query;
+ private boolean collectPayloads = true;
+
+ public NearSpansOrdered(SpanNearQuery spanNearQuery, IndexReader reader) throws IOException {
+ this(spanNearQuery, reader, true);
+ }
+
+ public NearSpansOrdered(SpanNearQuery spanNearQuery, IndexReader reader, boolean collectPayloads)
+ throws IOException {
+ if (spanNearQuery.getClauses().length < 2) {
+ throw new IllegalArgumentException("Less than 2 clauses: "
+ + spanNearQuery);
+ }
+ this.collectPayloads = collectPayloads;
+ allowedSlop = spanNearQuery.getSlop();
+ SpanQuery[] clauses = spanNearQuery.getClauses();
+ subSpans = new Spans[clauses.length];
+ matchPayload = new LinkedList<byte[]>();
+ subSpansByDoc = new Spans[clauses.length];
+ for (int i = 0; i < clauses.length; i++) {
+ subSpans[i] = clauses[i].getSpans(reader);
+ subSpansByDoc[i] = subSpans[i]; // used in toSameDoc()
+ }
+ query = spanNearQuery; // kept for toString() only.
+ }
+
+ // inherit javadocs
+ @Override
+ public int doc() { return matchDoc; }
+
+ // inherit javadocs
+ @Override
+ public int start() { return matchStart; }
+
+ // inherit javadocs
+ @Override
+ public int end() { return matchEnd; }
+
+ public Spans[] getSubSpans() {
+ return subSpans;
+ }
+
+ // TODO: Remove warning after API has been finalized
+ // TODO: Would be nice to be able to lazy load payloads
+ @Override
+ public Collection<byte[]> getPayload() throws IOException {
+ return matchPayload;
+ }
+
+ // TODO: Remove warning after API has been finalized
+ @Override
+ public boolean isPayloadAvailable() {
+ return matchPayload.isEmpty() == false;
+ }
+
+ // inherit javadocs
+ @Override
+ public boolean next() throws IOException {
+ if (firstTime) {
+ firstTime = false;
+ for (int i = 0; i < subSpans.length; i++) {
+ if (! subSpans[i].next()) {
+ more = false;
+ return false;
+ }
+ }
+ more = true;
+ }
+ if(collectPayloads) {
+ matchPayload.clear();
+ }
+ return advanceAfterOrdered();
+ }
+
+ // inherit javadocs
+ @Override
+ public boolean skipTo(int target) throws IOException {
+ if (firstTime) {
+ firstTime = false;
+ for (int i = 0; i < subSpans.length; i++) {
+ if (! subSpans[i].skipTo(target)) {
+ more = false;
+ return false;
+ }
+ }
+ more = true;
+ } else if (more && (subSpans[0].doc() < target)) {
+ if (subSpans[0].skipTo(target)) {
+ inSameDoc = false;
+ } else {
+ more = false;
+ return false;
+ }
+ }
+ if(collectPayloads) {
+ matchPayload.clear();
+ }
+ return advanceAfterOrdered();
+ }
+
+ /** Advances the subSpans to just after an ordered match with a minimum slop
+ * that is smaller than the slop allowed by the SpanNearQuery.
+ * @return true iff there is such a match.
+ */
+ private boolean advanceAfterOrdered() throws IOException {
+ while (more && (inSameDoc || toSameDoc())) {
+ if (stretchToOrder() && shrinkToAfterShortestMatch()) {
+ return true;
+ }
+ }
+ return false; // no more matches
+ }
+
+
+ /** Advance the subSpans to the same document */
+ private boolean toSameDoc() throws IOException {
+ ArrayUtil.mergeSort(subSpansByDoc, spanDocComparator);
+ int firstIndex = 0;
+ int maxDoc = subSpansByDoc[subSpansByDoc.length - 1].doc();
+ while (subSpansByDoc[firstIndex].doc() != maxDoc) {
+ if (! subSpansByDoc[firstIndex].skipTo(maxDoc)) {
+ more = false;
+ inSameDoc = false;
+ return false;
+ }
+ maxDoc = subSpansByDoc[firstIndex].doc();
+ if (++firstIndex == subSpansByDoc.length) {
+ firstIndex = 0;
+ }
+ }
+ for (int i = 0; i < subSpansByDoc.length; i++) {
+ assert (subSpansByDoc[i].doc() == maxDoc)
+ : " NearSpansOrdered.toSameDoc() spans " + subSpansByDoc[0]
+ + "\n at doc " + subSpansByDoc[i].doc()
+ + ", but should be at " + maxDoc;
+ }
+ inSameDoc = true;
+ return true;
+ }
+
+ /** Check whether two Spans in the same document are ordered.
+ * @param spans1
+ * @param spans2
+ * @return true iff spans1 starts before spans2
+ * or the spans start at the same position,
+ * and spans1 ends before spans2.
+ */
+ static final boolean docSpansOrdered(Spans spans1, Spans spans2) {
+ assert spans1.doc() == spans2.doc() : "doc1 " + spans1.doc() + " != doc2 " + spans2.doc();
+ int start1 = spans1.start();
+ int start2 = spans2.start();
+ /* Do not call docSpansOrdered(int,int,int,int) to avoid invoking .end() : */
+ return (start1 == start2) ? (spans1.end() < spans2.end()) : (start1 < start2);
+ }
+
+ /** Like {@link #docSpansOrdered(Spans,Spans)}, but use the spans
+ * starts and ends as parameters.
+ */
+ private static final boolean docSpansOrdered(int start1, int end1, int start2, int end2) {
+ return (start1 == start2) ? (end1 < end2) : (start1 < start2);
+ }
+
+ /** Order the subSpans within the same document by advancing all later spans
+ * after the previous one.
+ */
+ private boolean stretchToOrder() throws IOException {
+ matchDoc = subSpans[0].doc();
+ for (int i = 1; inSameDoc && (i < subSpans.length); i++) {
+ while (! docSpansOrdered(subSpans[i-1], subSpans[i])) {
+ if (! subSpans[i].next()) {
+ inSameDoc = false;
+ more = false;
+ break;
+ } else if (matchDoc != subSpans[i].doc()) {
+ inSameDoc = false;
+ break;
+ }
+ }
+ }
+ return inSameDoc;
+ }
+
+ /** The subSpans are ordered in the same doc, so there is a possible match.
+ * Compute the slop while making the match as short as possible by advancing
+ * all subSpans except the last one in reverse order.
+ */
+ private boolean shrinkToAfterShortestMatch() throws IOException {
+ matchStart = subSpans[subSpans.length - 1].start();
+ matchEnd = subSpans[subSpans.length - 1].end();
+ Set<byte[]> possibleMatchPayloads = new HashSet<byte[]>();
+ if (subSpans[subSpans.length - 1].isPayloadAvailable()) {
+ possibleMatchPayloads.addAll(subSpans[subSpans.length - 1].getPayload());
+ }
+
+ Collection<byte[]> possiblePayload = null;
+
+ int matchSlop = 0;
+ int lastStart = matchStart;
+ int lastEnd = matchEnd;
+ for (int i = subSpans.length - 2; i >= 0; i--) {
+ Spans prevSpans = subSpans[i];
+ if (collectPayloads && prevSpans.isPayloadAvailable()) {
+ Collection<byte[]> payload = prevSpans.getPayload();
+ possiblePayload = new ArrayList<byte[]>(payload.size());
+ possiblePayload.addAll(payload);
+ }
+
+ int prevStart = prevSpans.start();
+ int prevEnd = prevSpans.end();
+ while (true) { // Advance prevSpans until after (lastStart, lastEnd)
+ if (! prevSpans.next()) {
+ inSameDoc = false;
+ more = false;
+ break; // Check remaining subSpans for final match.
+ } else if (matchDoc != prevSpans.doc()) {
+ inSameDoc = false; // The last subSpans is not advanced here.
+ break; // Check remaining subSpans for last match in this document.
+ } else {
+ int ppStart = prevSpans.start();
+ int ppEnd = prevSpans.end(); // Cannot avoid invoking .end()
+ if (! docSpansOrdered(ppStart, ppEnd, lastStart, lastEnd)) {
+ break; // Check remaining subSpans.
+ } else { // prevSpans still before (lastStart, lastEnd)
+ prevStart = ppStart;
+ prevEnd = ppEnd;
+ if (collectPayloads && prevSpans.isPayloadAvailable()) {
+ Collection<byte[]> payload = prevSpans.getPayload();
+ possiblePayload = new ArrayList<byte[]>(payload.size());
+ possiblePayload.addAll(payload);
+ }
+ }
+ }
+ }
+
+ if (collectPayloads && possiblePayload != null) {
+ possibleMatchPayloads.addAll(possiblePayload);
+ }
+
+ assert prevStart <= matchStart;
+ if (matchStart > prevEnd) { // Only non overlapping spans add to slop.
+ matchSlop += (matchStart - prevEnd);
+ }
+
+ /* Do not break on (matchSlop > allowedSlop) here to make sure
+ * that subSpans[0] is advanced after the match, if any.
+ */
+ matchStart = prevStart;
+ lastStart = prevStart;
+ lastEnd = prevEnd;
+ }
+
+ boolean match = matchSlop <= allowedSlop;
+
+ if(collectPayloads && match && possibleMatchPayloads.size() > 0) {
+ matchPayload.addAll(possibleMatchPayloads);
+ }
+
+ return match; // ordered and allowed slop
+ }
+
+ @Override
+ public String toString() {
+ return getClass().getName() + "("+query.toString()+")@"+
+ (firstTime?"START":(more?(doc()+":"+start()+"-"+end()):"END"));
+ }
+}
+
fnp / pylucene.git / blobdiff