001// Copyright 2006, 2007, 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
015package org.apache.tapestry5.corelib.components;
016
017import org.apache.tapestry5.annotations.Parameter;
018import org.apache.tapestry5.corelib.base.AbstractConditional;
019
020/**
021 * Conditionally renders its body. May render its tag and any informal parameters.
022 * 
023 * @tapestrydoc
024 */
025public class If extends AbstractConditional
026{
027    /**
028     * If true, then the body of the If component is rendered. If false, the body is omitted.
029     */
030    @Parameter(required = true)
031    private boolean test;
032
033    /**
034     * Optional parameter to invert the test. If true, then the body is rendered when the test parameter is false (not
035     * true).
036     * 
037     * @see Unless
038     * @deprecated Since 5.3 as property expressions support the '!' invert operator
039     */
040    @Parameter
041    private boolean negate;
042
043    /**
044     * @return test parameter (if negate is false), or test parameter inverted (if negate is true)
045     */
046    protected boolean test()
047    {
048        return test != negate;
049    }
050
051}