001    /*
002     * Copyright 2005 Stephen J. McConnell.
003     *
004     * Licensed  under the  Apache License,  Version 2.0  (the "License");
005     * you may not use  this file  except in  compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     *   http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed  under the  License is distributed on an "AS IS" BASIS,
012     * WITHOUT  WARRANTIES OR CONDITIONS  OF ANY KIND, either  express  or
013     * implied.
014     *
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    
019    package net.dpml.state;
020    
021    /**
022     * Interface describing an application state.
023     *
024     * @author <a href="http://www.dpml.net">Digital Product Meta Library</a>
025     * @version 1.0.0
026     */
027    public interface State
028    {   
029       /**
030        * Constant artifact type for a state graph.
031        */
032        static final String TYPE = "state";
033         
034       /**
035        * Null state.
036        */
037        static final State NULL_STATE = new NullState();
038    
039       /**
040        * Return the name of the state.
041        * @return the state name
042        */
043        String getName();
044        
045       /**
046        * Set the parent state. 
047        * @param state the parent state
048        */
049        void setParent( State state );
050    
051       /**
052        * Return the parent state to this state or null if this is 
053        * the root of a state graph.
054        * @return the parent state
055        */
056        State getParent();
057        
058       /**
059        * Return the state path.  The path is composed of a sequence of 
060        * states from the root to this state.
061        * @return the state path
062        */
063        State[] getStatePath();
064        
065       /**
066        * Return the substates within this state.
067        * @return the substate array
068        */
069        State[] getStates();
070        
071       /**
072        * Return the array of triggers associated with the state.
073        * @return the trigger array
074        */
075        Trigger[] getTriggers();
076        
077       /**
078        * Return the array of transtions associated with the state.
079        * @return the transition array
080        */
081        Transition[] getTransitions();
082        
083       /**
084        * Return the array of operations associated with the state.
085        * @return the operation array
086        */
087        Operation[] getOperations();
088        
089       /**
090        * Return the array of management interfaces associated with 
091        * the state.
092        * @return the interfaces array
093        */
094        Interface[] getInterfaces();
095        
096       /**
097        * Test is the state is a terminal state.
098        * @return true if terminal
099        */
100        boolean isTerminal();
101    }