org.valid4j.ExceptionFactories Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of valid4j Show documentation

Simple assertion and validation library for Java

There is a newer version: 0.5.0

package org.valid4j;

import java.lang.reflect.Constructor;

import static org.hamcrest.CoreMatchers.notNullValue;
import static org.valid4j.Assertive.neverGetHereError;
import static org.valid4j.Assertive.require;

public class ExceptionFactories {

	private ExceptionFactories() {
		throw neverGetHereError("Prevent instantiation");
	}

	public static  ExceptionFactory exception(Class exceptionClass) {
		require(exceptionClass, notNullValue());
		Constructor constructor = findOneStringArgumentPublicConstructor(exceptionClass);
		if (constructor != null) {
			return new ExceptionOneStringArgumentFactory(constructor);
		} else {
			constructor = findNoArgumentPublicConstructor(exceptionClass);
			if (constructor != null) {
				return new ExceptionNoArgumentFactory(constructor);
			} else {
				throw neverGetHereError("Exception class must have a public constructor accepting one string argument or no arguments. (Note: Inner classes do not satisfy this condition)");
			}
		}
	}

	private static  Constructor findOneStringArgumentPublicConstructor(Class exceptionClass) {
		Constructor publicConstructors[] = exceptionClass.getConstructors();
		for (Constructor constructor : publicConstructors) {
			if (constructor.getParameterTypes().length != 1) {
				continue;
			}
			if (!constructor.getParameterTypes()[0].equals(String.class)) {
				continue;
			}
			return ((Constructor) constructor);
		}
		return null;
	}

	private static  Constructor findNoArgumentPublicConstructor(Class exceptionClass) {
		Constructor publicConstructors[] = exceptionClass.getConstructors();
		for (Constructor constructor : publicConstructors) {
			if (constructor.getParameterTypes().length != 0) {
				continue;
			}
			return ((Constructor) constructor);
		}
		return null;
	}

}