001    // Copyright 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.plastic;
016    
017    /**
018     * Condition used with {@link InstructionBuilder#when(Condition, WhenCallback)}. Most conditions
019     * pop the top element off the stack; some pop two elements.
020     */
021    public enum Condition
022    {
023        /** Is the top element of the stack null? */
024        NULL,
025    
026        /** Is the top element of the stack non-null? */
027        NON_NULL,
028    
029        /** Is the top element of the stack the integer zero? */
030        ZERO,
031    
032        /** Is the top element of the stack not the integer zero? */
033        NON_ZERO,
034    
035        /**
036         * Compare two integer elements on the stack; branch if the deeper
037         * element is less than the top element.
038         */
039        LESS_THAN,
040    
041        /**
042         * Compare two integer elements on the stack; branch if the deeper
043         * element equal to the top element.
044         */
045        EQUAL,
046    
047        /**
048         * Compare two integer elements on the stack; branch if the deeper
049         * element is not equal to the top element.
050         */
051        NOT_EQUAL,
052    
053        /**
054         * Compare two integer elements on the stack; branch if the deeper
055         * element is greater than the top element.
056         */
057        GREATER;
058    }