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    /**
018     * Provides context when evaluating an AST of {@link org.apache.hivemind.conditional.Node}s.
019     * Effectively, a wrapper around certain runtime operations.
020     * 
021     * @author Howard M. Lewis Ship
022     * @since 1.1
023     */
024    public interface EvaluationContext
025    {
026        /**
027         * Returns true if the given system property is set.
028         */
029    
030        public boolean isPropertySet(String propertyName);
031        
032        /**
033         * Returns true if the class, specified by FQCN, exists.
034         * 
035         */
036        
037        public boolean doesClassExist(String className);
038    }