/*
* 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.geode.internal.lang;
/**
* The ClassUtils class is an abstract utility class for working with and invoking methods on Class
* objects.
* <p/>
*
* @see java.lang.Class
* @see java.lang.Object
* @since GemFire 7.0
*/
public abstract class ClassUtils {
public static final Class[] EMPTY_CLASS_ARRAY = new Class[0];
/**
* Attempts to load the specified class by fully qualified name. If the class could not be found,
* then this method handles the ClassNotFoundException and throws the specified RuntimeException
* instead.
* </p>
*
* @param className a String indicating the fully qualified name of the class to load.
* @param e the RuntimeException to throw in place of the ClassNotFoundException if the class
* could not be found and loaded.
* @return a Class object representing the specified class by name.
* @throws NullPointerException if either className or RuntimeException is null.
* @see java.lang.Class#forName(String)
*/
public static Class forName(final String className, final RuntimeException e) {
try {
return Class.forName(className);
} catch (ClassNotFoundException ignore) {
throw e;
} catch (NoClassDefFoundError ignore) {
throw e;
}
}
/**
* Gets the Class type for the specified Object, or returns null if the Object reference is null.
* <p/>
*
* @param obj the Object who's class type is determined.
* @return the Class type of the Object parameter, or null if the Object reference is null.
* @see java.lang.Object#getClass()
*/
public static Class getClass(final Object obj) {
return (obj == null ? null : obj.getClass());
}
/**
* Gets the name of the Object's Class type or null if the Object reference is null.
* <p/>
*
* @param obj the Object's who's class name is returned or null if the Object reference is null.
* @return a String value specifying the name of the Object's class type.
* @see #getClass(Object)
* @see java.lang.Class#getName()
*/
public static String getClassName(final Object obj) {
final Class objType = getClass(obj);
return (objType == null ? null : objType.getName());
}
/**
* Determine whether the specified class is on the classpath. <
* <p/>
*
* @param className a String value specifying the fully-qualified name of the class.
* @return a boolean value indicating whether the specified class is on the classpath.
* @see #forName(String, RuntimeException)
*/
public static boolean isClassAvailable(final String className) {
try {
forName(className,
new IllegalArgumentException(String.format("Class (%1$s) is not available!", className)));
return true;
} catch (IllegalArgumentException ignore) {
// NOTE the Exception could be logged at fine/debug level if we used category-based logging
return false;
}
}
/**
* Determines whether the specified Object parameter is an instance of, or is
* assignment-compatible with the given Class type. Note, this method is null-safe for both Class
* and Object value references.
* <p/>
*
* @param type the Class type used in an instanceof determination with the given Object.
* @param obj the Object being determined for assignment-compatibility with the specified Class
* type.
* @return a boolean value indicating if the given Object is an instance of the specified Class
* type.
* @see java.lang.Class#isInstance(Object)
*/
public static boolean isInstanceOf(final Class type, final Object obj) {
return (type != null && type.isInstance(obj));
}
/**
* Determines whether the specified Object is not a instance of the following Class types. The
* Object is considered not an instance of the Class types if the condition holds for all Class
* types.
* <p/>
*
* @param obj the Object who's Class type is in question.
* @param types an array of Class types that the Object is being tested as an instance of.
* @return a boolean value of true if the Object is not an instance of any of the specified Class
* types.
* @see java.lang.Class#isInstance(Object)
*/
public static boolean isNotInstanceOf(final Object obj, final Class... types) {
boolean condition = true;
if (types != null) {
for (int index = 0; index < types.length && condition; index++) {
condition &= !types[index].isInstance(obj);
}
}
return condition;
}
}