/**
* Copyright 2014 National University of Ireland, Galway.
*
* This file is part of the SIREn project. Project and contact information:
*
* https://github.com/rdelbru/SIREn
*
* 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.
*/
package org.sindice.siren.qparser.keyword.builders;
import java.util.List;
import org.apache.lucene.queryparser.flexible.core.QueryNodeException;
import org.apache.lucene.queryparser.flexible.core.builders.QueryTreeBuilder;
import org.apache.lucene.queryparser.flexible.core.nodes.ModifierQueryNode;
import org.apache.lucene.queryparser.flexible.core.nodes.QueryNode;
import org.apache.lucene.search.Query;
import org.sindice.siren.qparser.keyword.nodes.DatatypeQueryNode;
import org.sindice.siren.qparser.keyword.nodes.NodeBooleanQueryNode;
import org.sindice.siren.search.node.NodeBooleanClause;
import org.sindice.siren.search.node.NodeBooleanQuery;
import org.sindice.siren.search.node.NodeQuery;
/**
* Builds a {@link NodeBooleanQuery} object from a {@link NodeBooleanQueryNode}
* object.
*
* <p>
*
* Every children in the {@link NodeBooleanQueryNode} object must be already tagged
* using {@link QueryTreeBuilder#QUERY_TREE_BUILDER_TAGID} with a {@link Query}
* object.
*
* <p>
*
* It takes in consideration if the children is a {@link ModifierQueryNode} to
* define the {@link NodeBooleanClause}.
*/
public class NodeBooleanQueryNodeBuilder implements KeywordQueryBuilder {
public NodeBooleanQueryNodeBuilder() {
}
public NodeQuery build(final QueryNode queryNode)
throws QueryNodeException {
final NodeBooleanQueryNode booleanNode = (NodeBooleanQueryNode) queryNode;
final List<QueryNode> children = booleanNode.getChildren();
final NodeBooleanQuery bq = new NodeBooleanQuery();
if (children == null) {
return bq; // return empty boolean query
}
// If more than one child, wrap them into a NodeBooleanQuery
if (children.size() > 1) {
for (final QueryNode child : children) {
final Object obj = child.getTag(QueryTreeBuilder.QUERY_TREE_BUILDER_TAGID);
if (obj != null) {
if (obj instanceof NodeQuery) {
final QueryNode mod;
if (child instanceof DatatypeQueryNode) {
mod = ((DatatypeQueryNode) child).getChild();
} else {
mod = child;
}
bq.add((NodeQuery) obj,
NodeQueryBuilderUtil.getModifierValue(mod, NodeBooleanClause.Occur.SHOULD));
}
else {
throw new QueryNodeException(new Error("Expected NodeQuery: got '" +
obj.getClass().getCanonicalName() + "'"));
}
}
}
return bq;
}
// If only one child, return it directly
else {
final Object obj = children.get(0).getTag(QueryTreeBuilder.QUERY_TREE_BUILDER_TAGID);
if (obj != null) {
if (obj instanceof NodeQuery) {
return (NodeQuery) obj;
}
else {
throw new QueryNodeException(new Error("Non NodeQuery query '" +
obj.getClass().getCanonicalName() + "' received"));
}
}
return bq; // return empty boolean query
}
}
}