package org.apache.lucene.queryParser.core.nodes;
/**
* 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 java.util.List;
import org.apache.lucene.messages.MessageImpl;
import org.apache.lucene.queryParser.core.QueryNodeError;
import org.apache.lucene.queryParser.core.QueryNodeException;
import org.apache.lucene.queryParser.core.messages.QueryParserMessages;
import org.apache.lucene.queryParser.core.parser.EscapeQuerySyntax;
/**
* A {@link BoostQueryNode} boosts the QueryNode tree which is under this node.
* So, it must only and always have one child.
*
* The boost value may vary from 0.0 to 1.0.
*
*/
public class BoostQueryNode extends QueryNodeImpl {
private static final long serialVersionUID = -3929082630855807593L;
private float value = 0;
/**
* Constructs a boost node
*
* @param query
* the query to be boosted
* @param value
* the boost value, it may vary from 0.0 to 1.0
*
* @throws QueryNodeException
*/
public BoostQueryNode(QueryNode query, float value) throws QueryNodeException {
if (query == null) {
throw new QueryNodeError(new MessageImpl(
QueryParserMessages.NODE_ACTION_NOT_SUPPORTED, "query", "null"));
}
this.value = value;
setLeaf(false);
allocate();
add(query);
}
/**
* Returns the single child which this node boosts.
*
* @return the single child which this node boosts
*/
public QueryNode getChild() {
List<QueryNode> children = getChildren();
if (children == null || children.size() == 0) {
return null;
}
return children.get(0);
}
/**
* Returns the boost value. It may vary from 0.0 to 1.0.
*
* @return the boost value
*/
public float getValue() {
return this.value;
}
/**
* Returns the boost value parsed to a string.
*
* @return the parsed value
*/
private CharSequence getValueString() {
Float f = Float.valueOf(this.value);
if (f == f.longValue())
return "" + f.longValue();
else
return "" + f;
}
@Override
public String toString() {
return "<boost value='" + getValueString() + "'>" + "\n"
+ getChild().toString() + "\n</boost>";
}
public CharSequence toQueryString(EscapeQuerySyntax escapeSyntaxParser) {
if (getChild() == null)
return "";
return getChild().toQueryString(escapeSyntaxParser) + "^"
+ getValueString();
}
@Override
public QueryNode cloneTree() throws CloneNotSupportedException {
BoostQueryNode clone = (BoostQueryNode) super.cloneTree();
clone.value = this.value;
return clone;
}
}