Reflection.java

package net.ion.rosetta.misc;

import java.util.HashMap;
import java.util.Map;

/**
 * Common utility for working with reflection.
 * 
 * @author Ben Yu
 */
final class Reflection {

	/** Gets the class name of {@code obj} or "null" if {@code obj} is null. */
	static String getClassName(Object obj) {
		return (obj == null) ? "null" : obj.getClass().getName();
	}

	@SuppressWarnings("unchecked")
	private static final Map<Class, Class> WRAPPERS = new HashMap<Class, Class>();

	private static <T> void primitive(Class<T> primitive, Class<T> wrapper) {
		WRAPPERS.put(primitive, wrapper);
	}

	static {
		primitive(byte.class, Byte.class);
		primitive(short.class, Short.class);
		primitive(int.class, Integer.class);
		primitive(long.class, Long.class);
		primitive(boolean.class, Boolean.class);
		primitive(float.class, Float.class);
		primitive(double.class, Double.class);
		primitive(char.class, Character.class);
		primitive(void.class, Void.class);
	}

	static <T> Class<T> wrapperClass(Class<T> type) {
		@SuppressWarnings("unchecked")
		Class<T> wrapperClass = WRAPPERS.get(type);
		return (wrapperClass == null) ? type : wrapperClass;
	}

	static boolean isInstance(Class<?> type, Object obj) {
		return wrapperClass(type).isInstance(obj);
	}

	static boolean isAssignable(Class<?> type, Object obj) {
		return obj == null ? !type.isPrimitive() : isInstance(type, obj);
	}
}