001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.scxml.semantics;
018    
019    /**
020     * Errors reported by the default SCXMLSemantics implementation.
021     *
022     */
023    public class ErrorConstants {
024    
025        /**
026         * Missing initial state for a composite state or for the scxml root.
027         *
028         * @see org.apache.commons.scxml.model.SCXML#getInitialState()
029         * @see org.apache.commons.scxml.model.State#getInitial()
030         */
031        public static final String NO_INITIAL = "NO_INITIAL";
032    
033        /**
034         * An initial state for a composite state whose Transition does not.
035         * Map to a descendant of the composite state.
036         *
037         */
038        public static final String ILLEGAL_INITIAL = "ILLEGAL_INITIAL";
039    
040        /**
041         * Unknown action - unsupported executable content. List of supported.
042         * actions: assign, cancel, elseif, else, if, log, send, var
043         */
044        public static final String UNKNOWN_ACTION = "UNKNOWN_ACTION";
045    
046        /**
047         * Illegal state machine configuration.
048         * Either a parallel exists which does not have all its AND sub-states
049         * active or there are multiple enabled OR states on the same level.
050         */
051        public static final String ILLEGAL_CONFIG = "ILLEGAL_CONFIG";
052    
053        /**
054         * Non-deterministic situation has occured - there are more than
055         * one enabled transitions in conflict.
056         *
057         * @deprecated Non deterministic behavior is now resolved using
058         *             state heirarchy and document order priorities.
059         */
060        public static final String NON_DETERMINISTIC = "NON_DETERMINISTIC";
061    
062        /**
063         * A variable referred to by assign name attribute is undefined.
064         */
065        public static final String UNDEFINED_VARIABLE = "UNDEFINED_VARIABLE";
066    
067        /**
068         * An expression language error.
069         */
070        public static final String EXPRESSION_ERROR = "EXPRESSION_ERROR";
071    
072        //---------------------------------------------- STATIC CONSTANTS ONLY
073    
074        /**
075         * Discourage instantiation.
076         */
077        private ErrorConstants() {
078            super(); // humor checkstyle
079        }
080    
081    }