Coverage Report - org.kuali.rice.krad.uif.service.ExpressionEvaluatorService
 
Classes in this File Line Coverage Branch Coverage Complexity
ExpressionEvaluatorService
N/A
N/A
1
 
 1  
 /**
 2  
  * Copyright 2005-2011 The Kuali Foundation
 3  
  *
 4  
  * Licensed under the Educational Community License, Version 2.0 (the "License");
 5  
  * you may not use this file except in compliance with the License.
 6  
  * You may obtain a copy of the License at
 7  
  *
 8  
  * http://www.opensource.org/licenses/ecl2.php
 9  
  *
 10  
  * Unless required by applicable law or agreed to in writing, software
 11  
  * distributed under the License is distributed on an "AS IS" BASIS,
 12  
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 13  
  * See the License for the specific language governing permissions and
 14  
  * limitations under the License.
 15  
  */
 16  
 package org.kuali.rice.krad.uif.service;
 17  
 
 18  
 import java.util.Map;
 19  
 
 20  
 /**
 21  
  * Provides evaluation of expression language statements against a given context
 22  
  *
 23  
  * <p>
 24  
  * Used within the UI framework to allow conditional logic to be configured through
 25  
  * the XML which can alter the values of component properties
 26  
  * </p>
 27  
  * 
 28  
  * @author Kuali Rice Team (rice.collab@kuali.org)
 29  
  */
 30  
 public interface ExpressionEvaluatorService {
 31  
 
 32  
     /**
 33  
      * Evaluates any el expressions that are found as a string property value
 34  
      * for the object
 35  
      * 
 36  
      * <p>
 37  
      * Using reflection the properties for the object are retrieved and if of
 38  
      * <code>String</code> type the corresponding value is retrieved. If the
 39  
      * value is not empty and contains the el placeholder see
 40  
      * {@link #containsElPlaceholder(String)} then the expression is evaluated
 41  
      * using the given context object and parameters. The evaluated string is
 42  
      * then set as the new property value, or in the case of a template
 43  
      * (expression contained within a literal string), the expression part is
 44  
      * replaced in the property value.
 45  
      * </p>
 46  
      * 
 47  
      * <p>
 48  
      * In addition to evaluating any property expressions, any configured
 49  
      * <code>PropertyReplacer</code> for the object are also evaluated and if a
 50  
      * match occurs those property replacements are made
 51  
      * </p>
 52  
      * 
 53  
      * @param object
 54  
      *            - object whose properties should be checked for expressions
 55  
      *            and evaluated
 56  
      * @param contextObject
 57  
      *            - context object for the expression evaluations
 58  
      * @param evaluationParameters
 59  
      *            - map of parameters that may appear in expressions, the map
 60  
      *            key gives the parameter name that may appear in the
 61  
      *            expression, and the map value is the object that expression
 62  
      *            should evaluate against when that name is found
 63  
      */
 64  
     public void evaluateObjectExpressions(Object object, Object contextObject, Map<String, Object> evaluationParameters);
 65  
 
 66  
     /**
 67  
      * Evaluates the given expression template string against the context object
 68  
      * and map of parameters
 69  
      * 
 70  
      * <p>
 71  
      * If the template string contains one or more el placeholders (see
 72  
      * {@link #containsElPlaceholder(String)}), the expression contained within
 73  
      * the placeholder will be evaluated and the corresponding value will be
 74  
      * substituted back into the property value where the placeholder occurred.
 75  
      * If no placeholders are found, the string will be returned unchanged
 76  
      * </p>
 77  
      * 
 78  
      * @param contextObject
 79  
      *            - context object for the expression evaluations
 80  
      * @param evaluationParameters
 81  
      *            - map of parameters that may appear in expressions, the map
 82  
      *            key gives the parameter name that may appear in the
 83  
      *            expression, and the map value is the object that expression
 84  
      *            should evaluate against when that name is found
 85  
      * @param expressionTemplate
 86  
      *            - string that should be evaluated for el expressions
 87  
      * @return String formed by replacing any el expressions in the original
 88  
      *         expression template with their corresponding evaluation results
 89  
      */
 90  
     public String evaluateExpressionTemplate(Object contextObject, Map<String, Object> evaluationParameters,
 91  
             String expressionTemplate);
 92  
 
 93  
     /**
 94  
      * Evaluates the given el expression against the content object and
 95  
      * parameters, and returns the result of the evaluation
 96  
      * 
 97  
      * <p>
 98  
      * The given expression string is assumed to be one el expression and should
 99  
      * not contain the el placeholders. The returned result depends on the
 100  
      * evaluation and what type is returns, for instance a boolean will be
 101  
      * return for a boolean expression, or a string for string expression
 102  
      * </p>
 103  
      * 
 104  
      * @param contextObject
 105  
      *            - context object for the expression evaluations
 106  
      * @param evaluationParameters
 107  
      *            - map of parameters that may appear in expressions, the map
 108  
      *            key gives the parameter name that may appear in the
 109  
      *            expression, and the map value is the object that expression
 110  
      *            should evaluate against when that name is found
 111  
      * @param expression
 112  
      *            - el expression to evaluate
 113  
      * @return Object result of the expression evaluation
 114  
      */
 115  
     public Object evaluateExpression(Object contextObject, Map<String, Object> evaluationParameters, String expression);
 116  
 
 117  
     /**
 118  
      * Indicates whether or not the given string contains the el placholder
 119  
      * (begin and end delimiters)
 120  
      * 
 121  
      * @param value
 122  
      *            - String to check for contained placeholders
 123  
      * @return boolean true if the string contains one or more placeholders,
 124  
      *         false if it contains none
 125  
      * @see org.kuali.rice.krad.uif.UifConstants.EL_PLACEHOLDER_PREFIX
 126  
      * @see org.kuali.rice.krad.uif.UifConstants.EL_PLACEHOLDER_SUFFIX
 127  
      */
 128  
     public boolean containsElPlaceholder(String value);
 129  
 }