Coverage report

| %line | %branch
--- | --- | ---
org.apache.commons.jexl.ExpressionFactory |
92% |
92% |

1 |  |
     /*
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      * Copyright 2002,2004 The Apache Software Foundation.
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      *
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      * Licensed under the Apache License, Version 2.0 (the "License");
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      * you may not use this file except in compliance with the License.
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      * You may obtain a copy of the License at
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      *
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      *      http://www.apache.org/licenses/LICENSE-2.0
9 |  |
      *
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      * Unless required by applicable law or agreed to in writing, software
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      * distributed under the License is distributed on an "AS IS" BASIS,
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      * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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      * See the License for the specific language governing permissions and
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      * limitations under the License.
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      */
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     package org.apache.commons.jexl;
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     import java.io.StringReader;
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     import org.apache.commons.jexl.parser.ASTExpressionExpression;
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     import org.apache.commons.jexl.parser.ASTReferenceExpression;
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     import org.apache.commons.jexl.parser.Parser;
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     import org.apache.commons.jexl.parser.SimpleNode;
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     import org.apache.commons.logging.Log;
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     import org.apache.commons.logging.LogFactory;
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     /**
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      * <p>
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      * Creates Expression objects.  To create a JEXL Expression object, pass
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      * valid JEXL syntax to the static createExpression() method:
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      * </p>
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      *
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      * <pre>
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      * String jexl = "array[1]";
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      * Expression expression = ExpressionFactory.createExpression( jexl );
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      * </pre>
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      *
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      * <p>
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      * When an {@link Expression} object is created, the JEXL syntax is
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      * parsed and verified.  If the supplied expression is neither an
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      * expression not a reference, an exception is thrown from createException().
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      * </p>
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      * @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
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      * @version $Id: ExpressionFactory.java,v 1.7 2004/08/23 13:50:00 dion Exp $
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      */
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     public class ExpressionFactory
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     {
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         /**
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          * The Log to which all ExpressionFactory messages will be logged.
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          */
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         protected static Log log =
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             LogFactory.getLog("org.apache.commons.jexl.ExpressionFactory");
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         /**
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          * The singleton ExpressionFactory also holds a single instance of {@link Parser}.
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          * When parsing expressions, ExpressionFactory synchronizes on Parser.
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          */
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         protected static Parser parser = new Parser(class="keyword">new StringReader(";")); //$NON-NLS-1$
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         /**
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          * ExpressionFactory is a single and this is the private
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          * status instance fufilling that pattern.
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          */
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         protected static ExpressionFactory ef = new ExpressionFactory();
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         /**
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          * Private constructor, the single instance is always obtained
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          * with a call to getInstance().
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          */
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         private ExpressionFactory(){}
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         /**
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          * Returns the single instance of ExpressionFactory.
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          * @return the instance of ExpressionFactory.
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          */
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         protected static  ExpressionFactory getInstance()
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         {
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             return ef;
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         }
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         /**
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          * Creates an Expression from a String containing valid
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          * JEXL syntax.  This method parses the expression which
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          * must contain either a reference or an expression.
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          * @param expression A String containing valid JEXL syntax
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          * @return An Expression object which can be evaluated with a JexlContext
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          * @throws Exception An exception can be thrown if there is a problem parsing
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          *                   his expression, or if the expression is neither an
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          *                   expression or a reference.
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          */
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         public static Expression createExpression(String expression)
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             throws Exception
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         {
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             return getInstance().createNewExpression(expression);
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         }
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         /**
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          *  Creates a new Expression based on the expression string.
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          *
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          *  @param expression valid Jexl expression
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          *  @return Expression
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          *  @throws Exception for a variety of reasons - mostly malformed
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          *          Jexl expression
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          */
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         protected Expression createNewExpression(String expression)
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             throws Exception {
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             String expr = cleanExpression(expression);
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             // Parse the Expression
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             SimpleNode tree;
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             synchronized(parser)
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             {
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                 log.debug( "Parsing expression: " + expr );
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                 tree = parser.parse(new StringReader(expr));
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             }
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             // Must be a simple reference or expression, otherwise
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             // throw an exception.
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             SimpleNode node = (SimpleNode) tree.jjtGetChild(0);
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             if( (node instanceof ASTReferenceExpression) ||
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                 (node instanceof ASTExpressionExpression) )
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             {
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                 node = (SimpleNode) node.jjtGetChild(0);
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                 Expression e = new ExpressionImpl(expression, node);
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                 return e;
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             }
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             else
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             {
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                 log.error( "Invalid Expression, node of type: " + node.getClass().getName() );
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                 throw new Exception("Invalid Expression: neither Reference nor Expression");
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             }
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         }
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         /**
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          * Trims the expression and adds a semi-colon if missing.
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          * @param expression to clean
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          * @return trimmed expression ending in a semi-colon
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          */
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         private String cleanExpression(String expression) {
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             String expr = expression.trim();
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             if (!expr.endsWith(";"))
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             {
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                 expr += ";";
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             }
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             return expr;
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         }
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     }

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