2009/05/20 - Apache Shale has been retired.

 /*

  * Licensed to the Apache Software Foundation (ASF) under one or more

  * contributor license agreements.  See the NOTICE file distributed with

  * this work for additional information regarding copyright ownership.

  * The ASF licenses this file to you under the Apache License, Version 2.0

  * (the "License"); you may not use this file except in compliance with

  * the License.  You may obtain a copy of the License at

  *

  *      http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.shale.dialog.basic.config;

 import java.util.HashMap;

 import java.util.Iterator;

 import java.util.Map;

 import org.apache.shale.dialog.basic.model.Dialog;

 import org.apache.shale.dialog.basic.model.State;

 import org.apache.shale.dialog.basic.model.Transition;

 /**

  * <p>{@link DialogImpl} is a basic implementation of {@link Dialog}.</p>

  *

  * @since 1.0.4

  */

 public final class DialogImpl implements Dialog {

     // ------------------------------------------------------ Instance Variables

     /**

      * <p>The class of a JavaBean to be instantiated as the initial

      * value of the <code>data</code> property of a newly instantiated

      * <code>DialogContext</code>.</p>

      */

     private Class dataClass = HashMap.class;

     /**

      * <p>Name of this {@link Dialog}.</p>

      */

     private String name = null;

     /**

      * <p>Name of the starting {@link State} for this {@link Dialog}.</p>

      */

     private String start = null;

     /**

      * <p>The {@link State}s owned by this {@link Dialog}, keyed by

      * identifier.</p>

      */

     private Map states = new HashMap();

     /**

      * <p>The global {@link Transition}s owned by this {@link Dialog}, keyed by

      * outcome.  Logic that performs transition management should first check

      * for a {@link Transition} associated with the origin {@link State}, then

      * consult the {@link Dialog} for a global definition.</p>

      */

     private Map transitions = new HashMap();

     // -------------------------------------------------------------- Properties

     /**

      * <p>Return the class of a JavaBean to be instantiated as the initial

      * value of the <code>data</code> property of a newly instantiated

      * <code>DialogContext</code>.</p>

      *

      * @return The JavaBean class whose instance becomes the <code>data</code>

      *         property of a new instance of this dialog

      */

     public Class getDataClass() {

         return this.dataClass;

     }

     /**

      * <p>Return the name of this {@link Dialog}.</p>

      *

      * @return The name of this {@link Dialog}

      */

     public String getName() {

         return this.name;

     }

     /**

      * <p>Return the name of the starting {@link State} for this

      * {@link Dialog}.</p>

      *

      * @return The starting state associated with this {@link Dialog}

      */

     public String getStart() {

         return this.start;

     }

     /**

      * <p>Return an <code>Iterator</code> over the names of {@link State}s

      * that are owned by this {@link Dialog}.  If there are no such

      * {@link State}s, an empty <code>Iterator</code> is returned.</p>

      *

      * @return An <code>Iterator</code> over all the {@link State}s in this

      *         {@link Dialog}

      */

     public Iterator getStateIds() {

         return this.states.keySet().iterator();

     }

     /**

      * <p>Return an <code>Iterator</code> over the logical outcomes of

      * global {@link Transition}s for this {@link Dialog}.  If there are

      * no such {@link Transition}s, an empty <code>Iterator</code> is

      * returned.</p>

      *

      * @return An <code>Iterator</code> over the logical outcomes of global

      *         {@link Transition}s for this {@link Dialog}

      */

     public Iterator getTransitionOutcomes() {

         return this.transitions.keySet().iterator();

     }

     // ---------------------------------------------------------- Public Methods

     /**

      * <p>Return the specified {@link State}, owned by this {@link Dialog},

      * if any.  Otherwise, return <code>null</code>.</p>

      *

      * @param id Identifier of the requested {@link State}

      * @return The {@link State} specified by the identifier, may be null

      */

     public State findState(String id) {

         return (State) states.get(id);

     }

     /**

      * <p>Return the global {@link Transition} for the specified logical outcome,

      * if any; otherwise, return <code>null</code>.</p>

      *

      * @param outcome Logical outcome for which to return a {@link Transition}

      * @return The global {@link Transition} for the specified logical outcome

      */

     public Transition findTransition(String outcome) {

         return (Transition) transitions.get(outcome);

     }

     /**

      * <p>Render a printable version of this instance.</p>

      *

      * @return A printable version of this instance

      */

     public String toString() {

         return "Dialog[name=" + this.name + ",start=" + this.start + "]";

     }

     // --------------------------------------------------- Configuration Methods

     /**

      * <p>Add the specified {@link State} to the {@link State}s owned by

      * this {@link Dialog}.</p>

      *

      * @param state {@link State} to be added

      *

      * @exception IllegalArgumentException if there is already a {@link State}

      *  with the specified <code>id</code> owned by this {@link Dialog}

      */

     public void addState(State state) throws IllegalArgumentException {

         if (states.containsKey(state.getName())) {

             throw new IllegalArgumentException(state.getName());

         }

         states.put(state.getName(), state);

         if (state instanceof AbstractState) {

             ((AbstractState) state).setDialog(this);

         }

     }

     /**

      * <p>Add the specified {@link Transition} to the global {@link Transition}s

      * associated with this {@link Dialog}.</p>

      *

      * @param transition {@link Transition} to be added

      *

      * @exception IllegalArgumentException if the specified {@link Transition}

      *  cannot be added to this {@link State}

      */

     public void addTransition(Transition transition) throws IllegalArgumentException {

         // FIXME - addTransition() - ignore duplicate outcomes for now

         transitions.put(transition.getOutcome(), transition);

     }

     /**

      * <p>Return the data class name for the <code>data</code> property

      * of a newly instantiated <code>DialogContext</code>.</p>

      *

      * @return The fully qualified class name whose instance becomes the

      *         <code>data</code> property of a new instance of this dialog

      */

     public String getDataClassName() {

         return dataClass.getName();

     }

     /**

      * <p>Set the data class name for the <code>data</code> property

      * of a newly instantiated <code>DialogContext</code>.</p>

      *

      * @param dataClassName New data class name

      *

      * @exception Exception if the specified class name cannot be loaded

      */

     public void setDataClassName(String dataClassName) {

         ClassLoader loader = Thread.currentThread().getContextClassLoader();

         if (loader == null) {

             loader = DialogImpl.class.getClassLoader();

         }

         try {

             this.dataClass = loader.loadClass(dataClassName);

         } catch (RuntimeException e) {

             throw e;

         } catch (Exception e) {

             throw new IllegalArgumentException(e.toString());

         }

     }

     /**

      * <p>Set the name of this {@link Dialog}.</p>

      *

      * @param name New name

      */

     public void setName(String name) {

         this.name = name;

     }

     /**

      * <p>Set the name of the starting {@link State} for this

      * {@link Dialog}.</p>

      *

      * @param start Name of the starting {@link State}

      */

     public void setStart(String start) {

         this.start = start;

     }

     /**

      * <p>Remove the specified {@link State} from the {@link State}s owned by

      * this {@link Dialog}, if it is currently registered.  Otherwise,

      * do nothing.</p>

      *

      * @param state {@link State} to be removed

      */

     public void removeState(State state) {

         states.remove(state.getName());

         if (state instanceof AbstractState) {

             ((AbstractState) state).setDialog(null);

         }

     }

     /**

      * <p>Remove the specified {@link Transition} from the global

      * {@link Transition}s associated with this {@link Dialog}, if it is

      * currently registered.  Otherwise, do nothing.</p>

      *

      * @param transition {@link Transition} to be removed

      */

     public void removeTransition(Transition transition) {

         transitions.remove(transition.getOutcome());

     }

 }