org.faktorips.util.ArgumentCheck Maven / Gradle / Ivy
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/*******************************************************************************
* Copyright (c) Faktor Zehn GmbH - faktorzehn.org
*
* This source code is available under the terms of the AGPL Affero General Public License version
* 3.
*
* Please see LICENSE.txt for full license terms, including the additional permissions and
* restrictions as well as the possibility of alternative license terms.
*******************************************************************************/
package org.faktorips.util;
import java.util.Collection;
import org.faktorips.annotation.UtilityClass;
import org.w3c.dom.Node;
/**
* A class that provides static methods to check method arguments, e.g. check if an argument is not
* null or is an instance of a specific class.
*
* All methods have an "optional" context parameter. If the check fails, the context's toString
* method is called and put into the IllegalArgumentException that is thrown. In this way you can
* provide some information in which context the check has failed and avoid to create a String
* object in the default case, when the check passes successfully.
*/
@UtilityClass
public class ArgumentCheck {
private ArgumentCheck() {
// Prohibit instantiation.
}
/**
* Checks if the indicated argument is not null.
*
* @param arg the argument to check.
*
* @throws NullPointerException if arg is null.
*/
public static final void notNull(Object arg) {
if (arg == null) {
throw new NullPointerException();
}
}
/**
* Checks if the provided array or one of the objects at the array's positions is null. If so a
* NullPointerException is thrown.
*
* @param arg the argument to check.
*/
public static final void notNull(Object[] arg) {
notNull((Object)arg);
for (Object element : arg) {
notNull(element);
}
}
/**
* Checks if the provided array or the objects at the array positions are null. If so a
* NullPointerException is thrown.
*
* @param arg the argument to check.
* @param context information, in case the test fails, the context's toString()
*/
public static final void notNull(Object[] arg, Object context) {
notNull((Object)arg);
for (Object element : arg) {
notNull(element, context);
}
}
/**
* Checks if the indicated argument is not null.
*
* @param arg the argument to check.
* @param context context information, in case the test fails, the context's toString() method
* is called and the result passed to the NullPointerException.
*
* @throws NullPointerException if arg is null.
*/
public static final void notNull(Object arg, Object context) {
if (arg == null) {
throw new NullPointerException("" + context);
}
}
/**
* Checks if the indicated argument is true.
*
* @param arg the argument to check.
*
* @throws NullPointerException if arg is null.
*/
public static final void isTrue(boolean arg) {
if (!arg) {
throw new IllegalArgumentException();
}
}
/**
* Checks if the indicated argument is true.
*
* @param arg the argument to check.
*
* @throws NullPointerException if arg is null.
*/
public static final void isTrue(boolean arg, Object context) {
if (!arg) {
throw new IllegalArgumentException(context.toString());
}
}
/**
* Checks if the indicated arguments are equal.
*
* @throws IllegalArgumentException if arg1.equals(arg2) returns falls.
*/
public static final void equals(Object arg1, Object arg2) {
if (!arg1.equals(arg2)) {
throw new IllegalArgumentException();
}
}
/**
* Checks if the indicated arguments are equal.
*
* @throws IllegalArgumentException if arg1.equals(arg2) returns falls.
*/
public static final void equals(Object arg1, Object arg2, Object context) {
if (!arg1.equals(arg2)) {
throw new IllegalArgumentException(context.toString());
}
}
/**
* Checks if the indicated argument is an instance of the indicated class.
*
* @param arg the argument to check.
*
* @throws IllegalArgumentException if arg is null.
*/
public static final void isInstanceOf(Object arg, Class clazz) {
if (!clazz.isAssignableFrom(arg.getClass())) {
throw new IllegalArgumentException();
}
}
/**
* Checks if the indicated argument is an instance of the indicated class.
*
* @param arg the argument to check.
*
* @throws IllegalArgumentException if arg is null.
*/
public static final void isInstanceOf(Object arg, Class clazz, Object context) {
if (!clazz.isAssignableFrom(arg.getClass())) {
throw new IllegalArgumentException(context.toString());
}
}
/**
* Checks if the indicated array has the indicated length.
*
* @param arg the array to check.
* @param length the expected array length
*
* @throws IllegalArgumentException if the array has not the given length.
*/
public static final void length(Object[] arg, int length) {
if (arg.length != length) {
throw new IllegalArgumentException();
}
}
/**
* Checks if the given collection has at least the given size.
*
* @param c the collection to check.
* @param size the expected array length
*
* @throws IllegalArgumentException if the array has not the given length.
*/
public static final void atLeast(Collection c, int size) {
if (c.size() < size) {
throw new IllegalArgumentException();
}
}
/**
* Checks if the indicated array has the indicated length.
*
* @param a the array to check.
* @param length the expected array length
* @param context an Object whose {@code toString} is used as the message for the
* IllegalArgumentException if it is thrown
*
* @throws IllegalArgumentException if the array has not the given length.
*/
public static final void length(Object[] a, int length, Object context) {
if (a.length != length) {
throw new IllegalArgumentException(context.toString());
}
}
/**
* Checks if the given subclass is a subclass of the given superclass.
*
* @throws IllegalArgumentException if subclass is not a subclass of superclass.
*/
public static final void isSubclassOf(Class subclass, Class superclass) {
if (!superclass.isAssignableFrom(subclass)) {
throw new IllegalArgumentException(subclass + " is not a subclass of " + superclass);
}
}
/**
* Checks if the given xml node has the given name.
*
* @throws IllegalArgumentException if the node has not the expected name.
* @throws NullPointerException if node is null.
*/
public static final void nodeName(Node node, String name) {
if (!node.getNodeName().equals(name)) {
throw new IllegalArgumentException("Node has name " + node.getNodeName() + ", expected " + name + ".");
}
}
}