View Javadoc

    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements.  See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache License, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License.  You may obtain a copy of the License at
    8    *
    9    *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   */
    17  package org.apache.commons.scxml.model;
    18
    19  import java.util.Collection;
    20
    21  import org.apache.commons.logging.Log;
    22  import org.apache.commons.scxml.Context;
    23  import org.apache.commons.scxml.ErrorReporter;
    24  import org.apache.commons.scxml.Evaluator;
    25  import org.apache.commons.scxml.EventDispatcher;
    26  import org.apache.commons.scxml.SCInstance;
    27  import org.apache.commons.scxml.SCXMLExpressionException;
    28  import org.apache.commons.scxml.TriggerEvent;
    29
    30  /***
    31   * The class in this SCXML object model that corresponds to the
    32   * &lt;var&gt; SCXML element.
    33   *
    34   */
    35  public class Var extends Action {
    36
    37      /***
    38       * Serial version UID.
    39       */
    40      private static final long serialVersionUID = 1L;
    41
    42      /***
    43       * The name of the variable to be created.
    44       */
    45      private String name;
    46
    47      /***
    48       * The expression that evaluates to the initial value of the variable.
    49       */
    50      private String expr;
    51
    52      /***
    53       * Constructor.
    54       */
    55      public Var() {
    56          super();
    57      }
    58
    59      /***
    60       * Get the expression that evaluates to the initial value
    61       * of the variable.
    62       *
    63       * @return String Returns the expr.
    64       */
    65      public final String getExpr() {
    66          return expr;
    67      }
    68
    69      /***
    70       * Set the expression that evaluates to the initial value
    71       * of the variable.
    72       *
    73       * @param expr The expr to set.
    74       */
    75      public final void setExpr(final String expr) {
    76          this.expr = expr;
    77      }
    78
    79      /***
    80       * Get the name of the (new) variable.
    81       *
    82       * @return String Returns the name.
    83       */
    84      public final String getName() {
    85          return name;
    86      }
    87
    88      /***
    89       * Set the name of the (new) variable.
    90       *
    91       * @param name The name to set.
    92       */
    93      public final void setName(final String name) {
    94          this.name = name;
    95      }
    96
    97      /***
    98       * {@inheritDoc}
    99       */
    100     public void execute(final EventDispatcher evtDispatcher,
    101             final ErrorReporter errRep, final SCInstance scInstance,
    102             final Log appLog, final Collection derivedEvents)
    103     throws ModelException, SCXMLExpressionException {
    104         Context ctx = scInstance.getContext(getParentState());
    105         Evaluator eval = scInstance.getEvaluator();
    106         ctx.setLocal(getNamespacesKey(), getNamespaces());
    107         Object varObj = eval.eval(ctx, expr);
    108         ctx.setLocal(getNamespacesKey(), null);
    109         ctx.setLocal(name, varObj);
    110         if (appLog.isDebugEnabled()) {
    111             appLog.debug("<var>: Defined variable '" + name
    112                 + "' with initial value '" + String.valueOf(varObj) + "'");
    113         }
    114         TriggerEvent ev = new TriggerEvent(name + ".change",
    115                 TriggerEvent.CHANGE_EVENT);
    116         derivedEvents.add(ev);
    117     }
    118
    119 }
    120