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 org.apache.lucene.messages.MessageImpl;
import org.apache.lucene.queryParser.core.QueryNodeError;
import org.apache.lucene.queryParser.core.messages.QueryParserMessages;
import org.apache.lucene.queryParser.core.parser.EscapeQuerySyntax;
/**
* A {@link SlopQueryNode} represents phrase query with a slop.
*
* From Lucene FAQ: Is there a way to use a proximity operator (like near or
* within) with Lucene? There is a variable called slop that allows you to
* perform NEAR/WITHIN-like queries. By default, slop is set to 0 so that only
* exact phrases will match. When using TextParser you can use this syntax to
* specify the slop: "doug cutting"~2 will find documents that contain
* "doug cutting" as well as ones that contain "cutting doug".
*/
public class SlopQueryNode extends QueryNodeImpl implements FieldableNode {
private static final long serialVersionUID = 0L;
private int value = 0;
/**
* @param query
* - QueryNode Tree with the phrase
* @param value
* - slop value
*/
public SlopQueryNode(QueryNode query, int value) {
if (query == null) {
throw new QueryNodeError(new MessageImpl(
QueryParserMessages.NODE_ACTION_NOT_SUPPORTED, "query", "null"));
}
this.value = value;
setLeaf(false);
allocate();
add(query);
}
public QueryNode getChild() {
return getChildren().get(0);
}
public int getValue() {
return this.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 "<slop value='" + getValueString() + "'>" + "\n"
+ getChild().toString() + "\n</slop>";
}
public CharSequence toQueryString(EscapeQuerySyntax escapeSyntaxParser) {
if (getChild() == null)
return "";
return getChild().toQueryString(escapeSyntaxParser) + "~"
+ getValueString();
}
@Override
public QueryNode cloneTree() throws CloneNotSupportedException {
SlopQueryNode clone = (SlopQueryNode) super.cloneTree();
clone.value = this.value;
return clone;
}
public CharSequence getField() {
QueryNode child = getChild();
if (child instanceof FieldableNode) {
return ((FieldableNode) child).getField();
}
return null;
}
public void setField(CharSequence fieldName) {
QueryNode child = getChild();
if (child instanceof FieldableNode) {
((FieldableNode) child).setField(fieldName);
}
}
}