Coverage Report - org.apache.commons.scxml.env.jexl.JexlEvaluator

Classes in this File Line Coverage Branch Coverage Complexity
JexlEvaluator
81% 
100% 
4.833

 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.env.jexl;
 18  
 
 19  
 import java.io.Serializable;
 20  
 import java.util.ArrayList;
 21  
 import java.util.HashMap;
 22  
 import java.util.List;
 23  
 import java.util.Map;
 24  
 import java.util.regex.Pattern;
 25  
 
 26  
 import org.apache.commons.jexl.Expression;
 27  
 import org.apache.commons.jexl.ExpressionFactory;
 28  
 import org.apache.commons.scxml.Context;
 29  
 import org.apache.commons.scxml.Evaluator;
 30  
 import org.apache.commons.scxml.SCXMLExpressionException;
 31  
 import org.w3c.dom.Node;
 32  
 
 33  
 /**
 34  
  * Evaluator implementation enabling use of JEXL expressions in
 35  
  * SCXML documents.
 36  
  *
 37  
  */
 38  
 public class JexlEvaluator implements Evaluator, Serializable {
 39  
 
 40  
     /** Serial version UID. */
 41  
     private static final long serialVersionUID = 1L;
 42  
 
 43  
     /** Error message if evaluation context is not a JexlContext. */
 44  
     private static final String ERR_CTX_TYPE = "Error evaluating JEXL "
 45  
         + "expression, Context must be a org.apache.commons.jexl.JexlContext";
 46  
 
 47  
     /** Pattern for recognizing the SCXML In() special predicate. */
 48  5
     private static Pattern inFct = Pattern.compile("In\\(");
 49  
     /** Pattern for recognizing the Commons SCXML Data() builtin function. */
 50  5
     private static Pattern dataFct = Pattern.compile("Data\\(");
 51  
 
 52  
     /** Constructor. */
 53  
     public JexlEvaluator() {
 54  36
         super();
 55  36
     }
 56  
 
 57  
     /**
 58  
      * Evaluate an expression.
 59  
      *
 60  
      * @param ctx variable context
 61  
      * @param expr expression
 62  
      * @return a result of the evaluation
 63  
      * @throws SCXMLExpressionException For a malformed expression
 64  
      * @see Evaluator#eval(Context, String)
 65  
      */
 66  
     public Object eval(final Context ctx, final String expr)
 67  
     throws SCXMLExpressionException {
 68  61
         if (expr == null) {
 69  0
             return null;
 70  
         }
 71  61
         JexlContext jexlCtx = null;
 72  61
         if (ctx instanceof JexlContext) {
 73  61
             jexlCtx = (JexlContext) ctx;
 74  
         } else {
 75  0
             throw new SCXMLExpressionException(ERR_CTX_TYPE);
 76  
         }
 77  61
         Expression exp = null;
 78  
         try {
 79  61
             String evalExpr = inFct.matcher(expr).
 80  
                 replaceAll("_builtin.isMember(_ALL_STATES, ");
 81  61
             evalExpr = dataFct.matcher(evalExpr).
 82  
                 replaceAll("_builtin.data(_ALL_NAMESPACES, ");
 83  61
             exp = ExpressionFactory.createExpression(evalExpr);
 84  61
             return exp.evaluate(getEffectiveContext(jexlCtx));
 85  0
         } catch (Exception e) {
 86  0
             throw new SCXMLExpressionException(e);
 87  
         }
 88  
     }
 89  
 
 90  
     /**
 91  
      * @see Evaluator#evalCond(Context, String)
 92  
      */
 93  
     public Boolean evalCond(final Context ctx, final String expr)
 94  
     throws SCXMLExpressionException {
 95  51
         if (expr == null) {
 96  0
             return null;
 97  
         }
 98  51
         JexlContext jexlCtx = null;
 99  51
         if (ctx instanceof JexlContext) {
 100  51
             jexlCtx = (JexlContext) ctx;
 101  
         } else {
 102  0
             throw new SCXMLExpressionException(ERR_CTX_TYPE);
 103  
         }
 104  51
         Expression exp = null;
 105  
         try {
 106  51
             String evalExpr = inFct.matcher(expr).
 107  
                 replaceAll("_builtin.isMember(_ALL_STATES, ");
 108  51
             evalExpr = dataFct.matcher(evalExpr).
 109  
                 replaceAll("_builtin.data(_ALL_NAMESPACES, ");
 110  51
             exp = ExpressionFactory.createExpression(evalExpr);
 111  51
             return (Boolean) exp.evaluate(getEffectiveContext(jexlCtx));
 112  0
         } catch (Exception e) {
 113  0
             throw new SCXMLExpressionException(e);
 114  
         }
 115  
     }
 116  
 
 117  
     /**
 118  
      * @see Evaluator#evalLocation(Context, String)
 119  
      */
 120  
     public Node evalLocation(final Context ctx, final String expr)
 121  
     throws SCXMLExpressionException {
 122  11
         if (expr == null) {
 123  0
             return null;
 124  
         }
 125  11
         JexlContext jexlCtx = null;
 126  11
         if (ctx instanceof JexlContext) {
 127  11
             jexlCtx = (JexlContext) ctx;
 128  
         } else {
 129  0
             throw new SCXMLExpressionException(ERR_CTX_TYPE);
 130  
         }
 131  11
         Expression exp = null;
 132  
         try {
 133  11
             String evalExpr = inFct.matcher(expr).
 134  
                 replaceAll("_builtin.isMember(_ALL_STATES, ");
 135  11
             evalExpr = dataFct.matcher(evalExpr).
 136  
                 replaceFirst("_builtin.dataNode(_ALL_NAMESPACES, ");
 137  11
             evalExpr = dataFct.matcher(evalExpr).
 138  
                 replaceAll("_builtin.data(_ALL_NAMESPACES, ");
 139  11
             exp = ExpressionFactory.createExpression(evalExpr);
 140  11
             return (Node) exp.evaluate(getEffectiveContext(jexlCtx));
 141  3
         } catch (Exception e) {
 142  3
             throw new SCXMLExpressionException(e);
 143  
         }
 144  
     }
 145  
 
 146  
     /**
 147  
      * Create a new child context.
 148  
      *
 149  
      * @param parent parent context
 150  
      * @return new child context
 151  
      * @see Evaluator#newContext(Context)
 152  
      */
 153  
     public Context newContext(final Context parent) {
 154  137
         return new JexlContext(parent);
 155  
     }
 156  
 
 157  
     /**
 158  
      * Create a new context which is the summation of contexts from the
 159  
      * current state to document root, child has priority over parent
 160  
      * in scoping rules.
 161  
      *
 162  
      * @param nodeCtx The JexlContext for this state.
 163  
      * @return The effective JexlContext for the path leading up to
 164  
      *         document root.
 165  
      */
 166  
     private JexlContext getEffectiveContext(final JexlContext nodeCtx) {
 167  123
         List contexts = new ArrayList();
 168  
         // trace path to root
 169  123
         JexlContext currentCtx = nodeCtx;
 170  434
         while (currentCtx != null) {
 171  311
             contexts.add(currentCtx);
 172  311
             currentCtx = (JexlContext) currentCtx.getParent();
 173  
         }
 174  123
         Map vars = new HashMap();
 175  
         // summation of the contexts, parent first, child wins
 176  434
         for (int i = contexts.size() - 1; i > -1; i--) {
 177  311
             vars.putAll(((JexlContext) contexts.get(i)).getVars());
 178  
         }
 179  123
         return new JexlContext(vars);
 180  
     }
 181  
 
 182  
 }
 183