org.apache.commons.lang.IllegalClassException Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.commons.lang;
/**
* Thrown when an object is an instance of an unexpected type (a class or interface).
* This exception supplements the standard IllegalArgumentException
* by providing a more semantically rich description of the problem.
*
* IllegalClassException represents the case where a method takes
* in a genericly typed parameter like Object (typically because it has to due to some
* other interface it implements), but this implementation only actually accepts a specific
* type, for example String. This exception would be used in place of
* IllegalArgumentException, yet it still extends it.
*
*
* public void foo(Object obj) {
* if (obj instanceof String == false) {
* throw new IllegalClassException(String.class, obj);
* }
* // do something with the string
* }
*
*
* @author Apache Software Foundation
* @author Matthew Hawthorne
* @author Gary Gregory
* @since 2.0
* @version $Id: IllegalClassException.java 905636 2010-02-02 14:03:32Z niallp $
*/
public class IllegalClassException extends IllegalArgumentException {
/**
* Required for serialization support.
*
* @see java.io.Serializable
*/
private static final long serialVersionUID = 8063272569377254819L;
/**
* Instantiates with the expected type, and actual object.
*
* @param expected the expected type
* @param actual the actual object
* @since 2.1
*/
public IllegalClassException(Class expected, Object actual) {
super(
"Expected: "
+ safeGetClassName(expected)
+ ", actual: "
+ (actual == null ? "null" : actual.getClass().getName()));
}
/**
* Instantiates with the expected and actual types.
*
* @param expected the expected type
* @param actual the actual type
*/
public IllegalClassException(Class expected, Class actual) {
super(
"Expected: "
+ safeGetClassName(expected)
+ ", actual: "
+ safeGetClassName(actual));
}
/**
* Instantiates with the specified message.
*
* @param message the exception message
*/
public IllegalClassException(String message) {
super(message);
}
/**
* Returns the class name or null if the class is
* null.
*
* @param cls a Class
* @return the name of cls, or null if if cls is null.
*/
private static final String safeGetClassName(Class cls) {
return cls == null ? null : cls.getName();
}
}