/**

  * Copyright 2005-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.krad.uif.component;

 import java.io.Serializable;

 import java.util.ArrayList;

 import java.util.List;

 import java.util.Map;

 /**

  * Configuration for replacing a property value based on a condition

  *

  * <p>

  * A <code>Component</code> may be configured with one or more <code>PropertyReplacer</code> instances. Each defines

  * a condition to evaluate during the apply model phase, and if that condition succeeds the property on the component

  * given by {@link #getPropertyName()}, will be replaced with the value given by {@link #getReplacement()}. Conditions

  * are defined using an expression language and may reference any variables available in the component's context.

  * </p>

  *

  * <p>

  * Property replacers can be used to change out an entire Component or List/Map of Components. For example, based on a

  * condition you might want to display a <code>TextControl</code> or <code>RadioControl</code> for an

  * <code>InputField</code>. You can define the field with a text control, then include a property replacer as

  * follows:

  * <pre>

         <bean parent="PropertyReplacer" p:propertyName="control"

               p:condition="field1 eq '10985'" p:replacement-ref="RadioControl"/>

  *

  * </pre>

  *

  * Note <code>Component</code> contains a <code>List</code> or property replacers which will be evaluated in the order

  * contained within the list. So in the above example if we wanted to now add a further condition which sets the control

  * to a checkbox, we would just add another property replacer bean.

  * <pre>

  *   <property name="propertyReplacers">

        <list>

         <bean parent="PropertyReplacer" p:propertyName="control"

               p:condition="field1 eq '10985'" p:replacement-ref="RadioControl"/>

         <bean parent="PropertyReplacer" p:propertyName="control"

               p:condition="field1 eq '11456'" p:replacement-ref="CheckboxControl"/>

  *     </list>

  *   </property>

  * </pre>

  *

  * Property replacers may be used to substitute primitive properties as well, such as Strings

  * </p>

  *

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public class PropertyReplacer extends ConfigurableBase implements Serializable {

     private static final long serialVersionUID = -8405429643299461398L;

     private String propertyName;

     private String condition;

     private Object replacement;

     public PropertyReplacer() {

         super();

     }

     /**

      * Returns a list of nested components

      *

      * <p>

      * All nested components will be returned in the list. Current assumption is that

      * <code>PropertyReplacer</code> can only contain a <code>Component</code>, <code>List</code> or

      * <code>Map</code> for nested components

      * </p>

      *

      * @return List<Component> nested components

      */

     public List<Component> getNestedComponents() {

         ArrayList<Component> nestedComponents = new ArrayList<Component>();

         if (replacement instanceof Component) {

             nestedComponents.add(((Component) replacement));

         } else if (replacement instanceof List) {

             for (Object replacementItem : (List<?>) replacement) {

                 if (replacementItem instanceof Component) {

                     nestedComponents.add((Component) replacementItem);

                 }

             }

         } else if (replacement instanceof Map) {

             for (Object replacementItem : ((Map<?, ?>) replacement).values()) {

                 if (replacementItem instanceof Component) {

                     nestedComponents.add((Component) replacementItem);

                 }

             }

         }

         return nestedComponents;

     }

     /**

      * Name of the property on the Component the property replacer is associated with that

      * will be set when the condition for the replacer succeeds

      *

      * <p>

      * Note the property name must be readable/writable on the component. The property name may

      * be nested, and include Map or List references.

      * </p>

      *

      * @return String property name to set

      */

     public String getPropertyName() {

         return this.propertyName;

     }

     /**

      * Setter for the property name that will be set

      *

      * @param propertyName

      */

     public void setPropertyName(String propertyName) {

         this.propertyName = propertyName;

     }

     /**

      * Gives the expression that should be evaluated to determine whether or not

      * the property replacement should be made

      *

      * <p>

      * Expression follows SPEL and may access any model data along with any variables

      * available in the context for the Component. The expression should evaluate to

      * a boolean. If the resulting boolean is true, the object given by {@link #getReplacement()}

      * will be set as the value for the associated property on the component. If the resulting

      * boolean is false, no action will take place

      * </p>

      *

      * <p>

      * Note the value does not need to contain the expression placeholder @{}

      * </p>

      *

      * @return String expression that should be evaluated

      * @see org.kuali.rice.krad.uif.service.ExpressionEvaluatorService

      * @see org.kuali.rice.krad.uif.UifConstants.ContextVariableNames

      */

     public String getCondition() {

         return this.condition;

     }

     /**

      * Setter for the replacement condition

      *

      * @param condition

      */

     public void setCondition(String condition) {

         this.condition = condition;

     }

     /**

      * Gives the Object that should be used to set the property value if the replacers condition

      * evaluates to true

      *

      * <p>

      * Note the configured Object must be valid for the type given by the property on the Component. Standard

      * property editors will be used for setting the property value

      * </p>

      *

      * @return Object instance to set

      */

     public Object getReplacement() {

         return this.replacement;

     }

     /**

      * Setter for the replacement Object

      *

      * @param replacement

      */

     public void setReplacement(Object replacement) {

         this.replacement = replacement;

     }

 }