Groovy example source code file (GroovyCastException.java)

This example Groovy source code file (GroovyCastException.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

cannot, class, class, classcastexception, exception, groovycastexception, groovycastexception, object, object, string, string, try

The Groovy GroovyCastException.java source code

/*
 * Copyright 2003-2010 the original author or authors.
 *
 * Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
 *
 * 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.codehaus.groovy.runtime.typehandling;

public class GroovyCastException extends ClassCastException {

    /**
     * @param objectToCast object we tried to cast
     * @param classToCastTo class we tried to cast to
     * @param cause not kept but we pass on message from this Exception if any
     */
    public GroovyCastException(Object objectToCast, Class classToCastTo, Exception cause) {
        super(makeMessage(objectToCast,classToCastTo) + " due to: " +
                cause.getClass().getName() + (cause.getMessage() == null ? "" : ": " + cause.getMessage()));
    }

    /**
     * @param objectToCast object we tried to cast
     * @param classToCastTo class we tried to cast to
     */
    public GroovyCastException(Object objectToCast, Class classToCastTo) {
        super(makeMessage(objectToCast,classToCastTo));
    }

    /**
     * @param message custom Exception message
     */
    public GroovyCastException(String message) {
        super(message);
    }

    private static String makeMessage(Object objectToCast, Class classToCastTo) {
       String classToCastFrom;
       Object msgObject = objectToCast;
       if (objectToCast!=null) {
           classToCastFrom = objectToCast.getClass().getName();
       } else {
           msgObject = "null";
           classToCastFrom = "null";
       }
       String msg = 
               "Cannot cast object '" + msgObject + "' " +
               "with class '" + classToCastFrom + "' " +
               "to class '" + classToCastTo.getName() + "'";

       if (objectToCast==null){
           msg += getWrapper(classToCastTo);
       }

       return msg;
    }

    private static String getWrapper(Class cls) {
        Class ncls = cls;
        if (cls==byte.class)        {ncls=Byte.class;}
        else if (cls==short.class)  {ncls=Short.class;}
        else if (cls==char.class)   {ncls=Character.class;}
        else if (cls==int.class)    {ncls=Integer.class;}
        else if (cls==long.class)   {ncls=Long.class;}
        else if (cls==float.class)  {ncls=Float.class;}
        else if (cls==double.class) {ncls=Double.class;}
        if (cls!=null && ncls!=cls) {
            String msg = ". Try '" + ncls.getName() + "' instead";
            return msg;
        }
        return "";
    }

}