/*

  * Copyright 2011 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 1.0 (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/ecl1.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.kns.uif.field;

 import org.apache.commons.lang.StringUtils;

 import org.kuali.rice.kns.uif.container.View;

 import org.kuali.rice.kns.uif.core.Component;

 import org.springframework.util.MethodInvoker;

 /**

  * Field instance whose output is produced by invoking a method

  * 

  * <p>

  * Generated fields can be used to produce any kind of HTML output using code.

  * The properties configured for the <code>GeneratedField</code> configure the

  * class and method that should be invoked to render the component. The method

  * that will be invoked should take the <code>GeneratedField</code> instance as

  * a parameter and return a String (which can include state HTML)

  * </p>

  * 

  * <p>

  * If the renderingMethodToCall is set, it is assumed to be a method on the

  * configured <code>ViewHelperService</code>. For invoking other class methods

  * the renderMethodInvoker must be configured

  * </p>

  * 

  * <p>

  * e.g. public String sayHiInBold(GeneratedField field) { return "<b>HI!</b>"; }

  * </p>

  * 

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

  */

 public class GeneratedField extends FieldBase {

         private static final long serialVersionUID = 1575182633700024203L;

         private static final org.apache.log4j.Logger LOG = org.apache.log4j.Logger.getLogger(GeneratedField.class);

         private String renderingMethodToCall;

         private MethodInvoker renderingMethodInvoker;

         private String renderOutput;

         public GeneratedField() {

                 super();

         }

         /**

          * The following finalization is done here:

          * 

          * <ul>

          * <li>Setup the method invoker and invoke method to get the render output</li>

          * </ul>

          * 

          * @see org.kuali.rice.kns.uif.core.ComponentBase#performFinalize(org.kuali.rice.kns.uif.container.View,

          *      java.lang.Object, org.kuali.rice.kns.uif.core.Component)

          */

         @Override

         public void performFinalize(View view, Object model, Component parent) {

                 super.performFinalize(view, model, parent);

                 if (renderingMethodInvoker == null) {

                         renderingMethodInvoker = new MethodInvoker();

                 }

                 // if method not set on invoker, use renderingMethodToCall

                 if (StringUtils.isBlank(renderingMethodInvoker.getTargetMethod())) {

                         renderingMethodInvoker.setTargetMethod(renderingMethodToCall);

                 }

                 // if target class or object not set, use view helper service

                 if ((renderingMethodInvoker.getTargetClass() == null) && (renderingMethodInvoker.getTargetObject() == null)) {

                         renderingMethodInvoker.setTargetObject(view.getViewHelperService());

                 }

                 // add the component instance as an argument

                 Object[] arguments = new Object[1];

                 arguments[0] = this;

                 renderingMethodInvoker.setArguments(arguments);

                 // invoke method and get render output

                 try {

                         LOG.debug("Invoking render method: " + renderingMethodInvoker.getTargetMethod() + " for component: "

                                         + getId());

                         renderingMethodInvoker.prepare();

                         renderOutput = (String) renderingMethodInvoker.invoke();

                 }

                 catch (Exception e) {

                         LOG.error("Error invoking rendering method for component: " + getId(), e);

                         throw new RuntimeException("Error invoking rendering method for component: " + getId(), e);

                 }

         }

         /**

          * Name of the method that should be invoked for rendering the component

          * (full method name, without parameters or return type)

          * 

          * <p>

          * Note the method can also be set with the renderingMethodInvoker

          * targetMethod property. If the method is on the configured

          * <code>ViewHelperService</code>, only this property needs to be configured

          * </p>

          * 

          * @return String method name

          */

         public String getRenderingMethodToCall() {

                 return this.renderingMethodToCall;

         }

         /**

          * Setter for the rendering method

          * 

          * @param renderingMethodToCall

          */

         public void setRenderingMethodToCall(String renderingMethodToCall) {

                 this.renderingMethodToCall = renderingMethodToCall;

         }

         /**

          * <code>MethodInvoker</code> instance for the method that should be invoked

          * for rendering the component

          * 

          * <p>

          * MethodInvoker can be configured to specify the class or object the method

          * should be called on. For static method invocations, the targetClass

          * property can be configured. For object invocations, that targetObject

          * property can be configured

          * </p>

          * 

          * @return MethodInvoker instance

          */

         public MethodInvoker getRenderingMethodInvoker() {

                 return this.renderingMethodInvoker;

         }

         /**

          * Setter for the method invoker instance

          * 

          * @param renderingMethodInvoker

          */

         public void setRenderingMethodInvoker(MethodInvoker renderingMethodInvoker) {

                 this.renderingMethodInvoker = renderingMethodInvoker;

         }

         /**

          * Rendering output for the component that will be sent as part of the

          * response (can contain static text and HTML)

          * 

          * @return String render output

          */

         public String getRenderOutput() {

                 return this.renderOutput;

         }

 }