package org.apache.lucene.search.spans;
/**
* Copyright 2004 The Apache Software Foundation
*
* Licensed 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 java.util.List;
import java.util.Collection;
import java.util.ArrayList;
import java.util.Iterator;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.util.PriorityQueue;
import org.apache.lucene.util.ToStringUtils;
import org.apache.lucene.search.Query;
/** Matches the union of its clauses.*/
public class SpanOrQuery extends SpanQuery {
private List clauses;
private String field;
/** Construct a SpanOrQuery merging the provided clauses. */
public SpanOrQuery(SpanQuery[] clauses) {
// copy clauses array into an ArrayList
this.clauses = new ArrayList(clauses.length);
for (int i = 0; i < clauses.length; i++) {
SpanQuery clause = clauses[i];
if (i == 0) { // check field
field = clause.getField();
} else if (!clause.getField().equals(field)) {
throw new IllegalArgumentException("Clauses must have same field.");
}
this.clauses.add(clause);
}
}
/** Return the clauses whose spans are matched. */
public SpanQuery[] getClauses() {
return (SpanQuery[])clauses.toArray(new SpanQuery[clauses.size()]);
}
public String getField() { return field; }
public Collection getTerms() {
Collection terms = new ArrayList();
Iterator i = clauses.iterator();
while (i.hasNext()) {
SpanQuery clause = (SpanQuery)i.next();
terms.addAll(clause.getTerms());
}
return terms;
}
public Query rewrite(IndexReader reader) throws IOException {
SpanOrQuery clone = null;
for (int i = 0 ; i < clauses.size(); i++) {
SpanQuery c = (SpanQuery)clauses.get(i);
SpanQuery query = (SpanQuery) c.rewrite(reader);
if (query != c) { // clause rewrote: must clone
if (clone == null)
clone = (SpanOrQuery) this.clone();
clone.clauses.set(i,query);
}
}
if (clone != null) {
return clone; // some clauses rewrote
} else {
return this; // no clauses rewrote
}
}
public String toString(String field) {
StringBuffer buffer = new StringBuffer();
buffer.append("spanOr([");
Iterator i = clauses.iterator();
while (i.hasNext()) {
SpanQuery clause = (SpanQuery)i.next();
buffer.append(clause.toString(field));
if (i.hasNext()) {
buffer.append(", ");
}
}
buffer.append("])");
buffer.append(ToStringUtils.boost(getBoost()));
return buffer.toString();
}
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
final SpanOrQuery that = (SpanOrQuery) o;
if (!clauses.equals(that.clauses)) return false;
if (!field.equals(that.field)) return false;
return getBoost() == that.getBoost();
}
public int hashCode() {
int h = clauses.hashCode();
h ^= (h << 10) | (h >>> 23);
h ^= Float.floatToRawIntBits(getBoost());
return h;
}
private class SpanQueue extends PriorityQueue {
public SpanQueue(int size) {
initialize(size);
}
protected final boolean lessThan(Object o1, Object o2) {
Spans spans1 = (Spans)o1;
Spans spans2 = (Spans)o2;
if (spans1.doc() == spans2.doc()) {
if (spans1.start() == spans2.start()) {
return spans1.end() < spans2.end();
} else {
return spans1.start() < spans2.start();
}
} else {
return spans1.doc() < spans2.doc();
}
}
}
public Spans getSpans(final IndexReader reader) throws IOException {
if (clauses.size() == 1) // optimize 1-clause case
return ((SpanQuery)clauses.get(0)).getSpans(reader);
return new Spans() {
private List all = new ArrayList(clauses.size());
private SpanQueue queue = new SpanQueue(clauses.size());
{
Iterator i = clauses.iterator();
while (i.hasNext()) { // initialize all
all.add(((SpanQuery)i.next()).getSpans(reader));
}
}
private boolean firstTime = true;
public boolean next() throws IOException {
if (firstTime) { // first time -- initialize
for (int i = 0; i < all.size(); i++) {
Spans spans = (Spans)all.get(i);
if (spans.next()) { // move to first entry
queue.put(spans); // build queue
} else {
all.remove(i--);
}
}
firstTime = false;
return queue.size() != 0;
}
if (queue.size() == 0) { // all done
return false;
}
if (top().next()) { // move to next
queue.adjustTop();
return true;
}
all.remove(queue.pop()); // exhausted a clause
return queue.size() != 0;
}
private Spans top() { return (Spans)queue.top(); }
public boolean skipTo(int target) throws IOException {
if (firstTime) {
for (int i = 0; i < all.size(); i++) {
Spans spans = (Spans)all.get(i);
if (spans.skipTo(target)) { // skip each spans in all
queue.put(spans); // build queue
} else {
all.remove(i--);
}
}
firstTime = false;
} else {
while (queue.size() != 0 && top().doc() < target) {
if (top().skipTo(target)) {
queue.adjustTop();
} else {
all.remove(queue.pop());
}
}
}
return queue.size() != 0;
}
public int doc() { return top().doc(); }
public int start() { return top().start(); }
public int end() { return top().end(); }
public String toString() {
return "spans("+SpanOrQuery.this+")@"+
(firstTime?"START"
:(queue.size()>0?(doc()+":"+start()+"-"+end()):"END"));
}
};
}
}
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