001/*
002 *  Copyright 2010 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.plugins.repository.query.expression;
017
018import org.apache.commons.lang.StringUtils;
019
020
021/**
022 * Constructs an {@link Expression} corresponding to the logical "or"
023 * between two others {@link Expression}.
024 */
025public class OrExpression implements Expression
026{
027    private Expression[] _exprs;
028
029    /**
030     * Creates the "or" Expression.
031     * @param exprs the operands
032     */
033    public OrExpression(Expression ... exprs)
034    {
035        _exprs = exprs;
036    }
037
038    public String build()
039    {
040        if (_exprs.length == 1 && _exprs[0] != null)
041        {
042            return _exprs[0].build();
043        }
044        
045        boolean isFirst = true;
046        StringBuilder sb = new StringBuilder("(");
047        
048        for (Expression expr : _exprs)
049        {
050            if (expr != null)
051            {
052                String exprAsString = expr.build();
053                if (StringUtils.isNotBlank(exprAsString))
054                {
055                    if (isFirst)
056                    {
057                        isFirst = false;
058                    }
059                    else
060                    {
061                        sb.append(" or ");
062                    }
063                    sb.append(exprAsString);
064                }                
065            }
066        }
067        
068        if (isFirst)
069        {
070            return "";
071        }
072        else
073        {
074            return sb.append(")").toString();
075        }
076    }
077}