001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.hivemind.conditional;
016    
017    import org.apache.hivemind.ApplicationRuntimeException;
018    import org.apache.hivemind.ClassResolver;
019    import org.apache.hivemind.util.Defense;
020    
021    /**
022     * @author Howard M. Lewis Ship
023     */
024    public class EvaluationContextImpl implements EvaluationContext
025    {
026        private ClassResolver _resolver;
027    
028        public EvaluationContextImpl(ClassResolver resolver)
029        {
030            Defense.notNull(resolver, "resolver");
031    
032            _resolver = resolver;
033        }
034    
035        public boolean isPropertySet(String propertyName)
036        {
037            return Boolean.getBoolean(propertyName);
038        }
039    
040        public boolean doesClassExist(String className)
041        {
042            try
043            {
044                _resolver.findClass(className);
045    
046                return true;
047            }
048            catch (ApplicationRuntimeException ex)
049            {
050                return false;
051            }
052        }
053    
054    }