001    // Copyright 2006, 2007 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.tapestry5.corelib.components;
016    
017    import org.apache.tapestry5.annotations.Parameter;
018    import org.apache.tapestry5.corelib.base.AbstractConditional;
019    
020    /**
021     * Conditionally renders its body. May render its tag and any informal parameters.
022     */
023    public class If extends AbstractConditional
024    {
025        /**
026         * If true, then the body of the If component is rendered. If false, the body is omitted.
027         */
028        @Parameter(required = true)
029        private boolean test;
030    
031        /**
032         * Optional parameter to invert the test. If true, then the body is rendered when the test parameter is false (not
033         * true).
034         *
035         * @see Unless
036         */
037        @Parameter
038        private boolean negate;
039    
040        /**
041         * @return test parameter (if negate is false), or test parameter inverted (if negate is true)
042         */
043        protected boolean test()
044        {
045            return test != negate;
046        }
047    
048    
049    }