001/*
002 *  Copyright 2014 Anyware Services
003 *
004 *  Licensed under the Apache License, Version 2.0 (the "License");
005 *  you may not use this file except in compliance with the License.
006 *  You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 *  Unless required by applicable law or agreed to in writing, software
011 *  distributed under the License is distributed on an "AS IS" BASIS,
012 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 *  See the License for the specific language governing permissions and
014 *  limitations under the License.
015 */
016package org.ametys.cms.search.query;
017
018/**
019 * Represents a {@link Query} corresponding to the logical negation of another {@link Query}.
020 */
021public class NotQuery implements Query
022{
023    /** The prefix for making a query negative. */
024    public static final String NEGATION_QUERY_PREFIX = "*:* -";
025    
026    /** The negated query. */
027    protected Query _query;
028    
029    /**
030     * Build a NotQuery object.
031     * @param query the negated query.
032     */
033    public NotQuery(Query query)
034    {
035        _query = query;
036    }
037    
038    /**
039     * Get the negated query.
040     * @return the negated query.
041     */
042    public Query getQuery()
043    {
044        return _query;
045    }
046    
047    /**
048     * Appends a negation to the query being built.
049     * <br>This method just does <code>sb.append({@value #NEGATION_QUERY_PREFIX});</code>
050     * @param query The query builder
051     * @return The given query builder
052     */
053    public static StringBuilder appendNegation(StringBuilder query)
054    {
055        query.append(NEGATION_QUERY_PREFIX);
056        return query;
057    }
058    
059    @Override
060    public String build() throws QuerySyntaxException
061    {
062        String queryString = _query.build();
063        if (queryString.isEmpty())
064        {
065            return "";
066        }
067        else
068        {
069            return "(" + NEGATION_QUERY_PREFIX + "(" + _query.build() + "))";
070        }
071    }
072
073    @Override
074    public int hashCode()
075    {
076        final int prime = 31;
077        int result = 1;
078        result = prime * result + ((_query == null) ? 0 : _query.hashCode());
079        return result;
080    }
081
082    @Override
083    public boolean equals(Object obj)
084    {
085        if (this == obj)
086        {
087            return true;
088        }
089        if (obj == null)
090        {
091            return false;
092        }
093        if (getClass() != obj.getClass())
094        {
095            return false;
096        }
097        NotQuery other = (NotQuery) obj;
098        if (_query == null)
099        {
100            if (other._query != null)
101            {
102                return false;
103            }
104        }
105        else if (!_query.equals(other._query))
106        {
107            return false;
108        }
109        return true;
110    }
111}