com.cedarsoftware.util.Convention Maven / Gradle / Ivy
package com.cedarsoftware.util;
import java.util.Map;
/**
* Utility class containing common defensive programming helpers.
*
* {@code Convention} offers a set of static convenience methods for
* validating method arguments such as null checks or ensuring that a
* string is not empty. The class is not intended to be instantiated.
*/
public class Convention {
/**
* statically accessed class
*/
private Convention() {
}
/**
* Throws an exception if null
*
* @param value object to check if null
* @param message message to use when thrown
* @throws IllegalArgumentException if the string passed in is null or empty
*/
public static void throwIfNull(Object value, String message) {
if (value == null) {
throw new IllegalArgumentException(message);
}
}
/**
* Throws an exception if null or empty
*
* @param value string to check
* @param message message to use when thrown
* @throws IllegalArgumentException if the string passed in is null or empty
*/
public static void throwIfNullOrEmpty(String value, String message) {
if (StringUtilities.isEmpty(value)) {
throw new IllegalArgumentException(message);
}
}
/**
* Verify that the supplied class can be loaded.
*
* @param fullyQualifiedClassName fully qualified name of the class to look up
* @param loader the {@link ClassLoader} used to locate the class
* @throws IllegalArgumentException if the class cannot be resolved
*/
public static void throwIfClassNotFound(String fullyQualifiedClassName, ClassLoader loader) {
throwIfNullOrEmpty(fullyQualifiedClassName, "fully qualified ClassName cannot be null or empty");
throwIfNull(loader, "loader cannot be null");
Class c = ClassUtilities.forName(fullyQualifiedClassName, loader);
if (c == null) {
throw new IllegalArgumentException("Unknown class: " + fullyQualifiedClassName + " was not found.");
}
}
public static void throwIfKeyExists(Map map, K key, String message) {
throwIfNull(map, "map cannot be null");
throwIfNull(key, "key cannot be null");
if (map.containsKey(key)) {
throw new IllegalArgumentException(message);
}
}
/**
* Throws an exception if the logic is false.
*
* @param logic test to see if we need to throw the exception.
* @param message to include in the exception explaining why the the assertion failed
*/
public static void throwIfFalse(boolean logic, String message) {
if (!logic) {
throw new IllegalArgumentException(message);
}
}
}