001    // Copyright 2008, 2011 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     * A close relative of the {@link org.apache.tapestry5.corelib.components.If} component that inverts the meaning of its
022     * test. This is easier than an {@link org.apache.tapestry5.corelib.components.If} component with the negate parameter set to {@code true}.
023     * 
024     * @tapestrydoc
025     */
026    public class Unless extends AbstractConditional
027    {
028        /**
029         * If true, then the body of the component is omitted. If false, the body is rendered.
030         */
031        @Parameter(required = true)
032        private boolean test;
033    
034        /**
035         * @return test parameter inverted
036         */
037        protected boolean test()
038        {
039            return !test;
040        }
041    }