org.apache.lucene.search.grouping.AllGroupsCollector Maven / Gradle / Ivy
/*
* 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.grouping;
import java.io.IOException;
import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
import org.apache.lucene.index.LeafReaderContext;
import org.apache.lucene.search.Scorable;
import org.apache.lucene.search.ScoreMode;
import org.apache.lucene.search.SimpleCollector;
/**
* A collector that collects all groups that match the
* query. Only the group value is collected, and the order
* is undefined. This collector does not determine
* the most relevant document of a group.
*
* @lucene.experimental
*/
public class AllGroupsCollector extends SimpleCollector {
private final GroupSelector groupSelector;
private final Set groups = new HashSet();
/**
* Create a new AllGroupsCollector
* @param groupSelector the GroupSelector to determine groups
*/
public AllGroupsCollector(GroupSelector groupSelector) {
this.groupSelector = groupSelector;
}
/**
* Returns the total number of groups for the executed search.
* This is a convenience method. The following code snippet has the same effect: getGroups().size()
*
* @return The total number of groups for the executed search
*/
public int getGroupCount() {
return getGroups().size();
}
/**
* Returns the group values
*
* This is an unordered collections of group values.
*
* @return the group values
*/
public Collection getGroups() {
return groups;
}
@Override
public void setScorer(Scorable scorer) throws IOException {}
@Override
protected void doSetNextReader(LeafReaderContext context) throws IOException {
groupSelector.setNextReader(context);
}
@Override
public void collect(int doc) throws IOException {
groupSelector.advanceTo(doc);
if (groups.contains(groupSelector.currentValue()))
return;
groups.add(groupSelector.copyValue());
}
@Override
public ScoreMode scoreMode() {
return ScoreMode.COMPLETE_NO_SCORES; // the result is unaffected by relevancy
}
}