/*

  * 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.krms.api.engine;

 import org.kuali.rice.core.api.exception.RiceRuntimeException;

 /**

  * An exception which indicates that the type of data being evaluated in the

  * engine does not match the expected type.

  * 

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

  *

  */

 public class IncompatibleTypeException extends RiceRuntimeException {

         private static final long serialVersionUID = -8359509154258982033L;

         private final Object value;

         private final Class<?>[] validTypes;

         /**

          * Constructs an IncompatibleTypeException with a reference to the object

          * being checked and an array of valid Class objects which the type failed

          * to match.

          * 

          * <p>A message describing the nature of the incompatible types will

          * automatically be generated and can be retrieved through {@link #getMessage()}

          * 

          * @param value the object which was being evaluated against a set of valid types

          * @param validTypes the valid types against which the value was being evaluated

          * but failed to be compatible with

          */

         public IncompatibleTypeException(Object value, Class<?>... validTypes) {

                 this(null, value, validTypes);

         }

         /**

          * Constructs an IncompatibleTypeException with a message, a reference to the object

          * being checked, and an array of valid Class objects which the type failed

          * to match.

          * 

          * <p>The additional message will be prepended to the front of an automatically

          * generated message describing the nature of the incompatible types and can be

          * retrieved through {@link #getMessage()}.

          * 

          * @param additionalMessage the additional message to prepend to the generated exception detail message

          * @param value the object which was being evaluated against a set of valid types

          * @param validTypes the valid types against which the value was being evaluated

          * but failed to be compatible with

          */

         public IncompatibleTypeException(String additionalMessage, Object value, Class<?>... validTypes) {

                 super(constructMessage(additionalMessage, value, validTypes));

                 this.value = value;

                 this.validTypes = validTypes;

         }

         private static String constructMessage(String additionalMessage, Object value, Class<?>... validTypes) {

                 StringBuilder message = new StringBuilder();

                 if (additionalMessage != null) {

                         message.append(additionalMessage);

                 }

                 if (message.length() > 0) {

                         message.append(" -> ");

                 }

                 if (validTypes != null && validTypes.length > 0) {        

                         message.append("Type should have been one of [");

                         for (Class<?> validType : validTypes) {

                                 message.append(validType.getName()).append(", ");

                         }

                         // trim off the last two character to get rid of the last ", "

                         message.delete(message.length() - 2, message.length());

                         message.append("] but was ").append(value == null ? "null" : value.getClass().getName());

                 } else {

                         message.append("Type was ").append(value == null ? "null" : value.getClass().getName());        

                 }

                 return message.toString();

         }

         /**

          * Returns the object which triggered the incompatible type exception.

          * 

          * @return the value passed to this exception upon construction

          */

         public Object getValue() {

                 return value;

         }

         /**

          * Returns the array of Class objects which include the types against

          * which the object value was deemed incompatible.

          * 

          * @return the valid types passed to this exception upon construction

          */

         public Class<?>[] getValidTypes() {

                 return validTypes;

         }

 }