reflectionutils.java

来自「spring framework 2.5.4源代码」· Java 代码 · 共 561 行 · 第 1/2 页

	}

	/**
	 * Throws an IllegalStateException with the given exception as root cause.
	 * @param ex the unexpected exception
	 */
	private static void handleUnexpectedException(Throwable ex) {
		// Needs to avoid the chained constructor for JDK 1.4 compatibility.
		IllegalStateException isex = new IllegalStateException("Unexpected exception thrown");
		isex.initCause(ex);
		throw isex;
	}

	/**
	 * Determine whether the given method explicitly declares the given exception
	 * or one of its superclasses, which means that an exception of that type
	 * can be propagated as-is within a reflective invocation.
	 * @param method the declaring method
	 * @param exceptionType the exception to throw
	 * @return <code>true</code> if the exception can be thrown as-is;
	 * <code>false</code> if it needs to be wrapped
	 */
	public static boolean declaresException(Method method, Class exceptionType) {
		Assert.notNull(method, "Method must not be null");
		Class[] declaredExceptions = method.getExceptionTypes();
		for (int i = 0; i < declaredExceptions.length; i++) {
			Class declaredException = declaredExceptions[i];
			if (declaredException.isAssignableFrom(exceptionType)) {
				return true;
			}
		}
		return false;
	}


	/**
	 * Determine whether the given field is a "public static final" constant.
	 * @param field the field to check
	 */
	public static boolean isPublicStaticFinal(Field field) {
		int modifiers = field.getModifiers();
		return (Modifier.isPublic(modifiers) && Modifier.isStatic(modifiers) && Modifier.isFinal(modifiers));
	}

	/**
	 * Make the given field accessible, explicitly setting it accessible if necessary.
	 * The <code>setAccessible(true)</code> method is only called when actually necessary,
	 * to avoid unnecessary conflicts with a JVM SecurityManager (if active).
	 * @param field the field to make accessible
	 * @see java.lang.reflect.Field#setAccessible
	 */
	public static void makeAccessible(Field field) {
		if (!Modifier.isPublic(field.getModifiers()) ||
				!Modifier.isPublic(field.getDeclaringClass().getModifiers())) {
			field.setAccessible(true);
		}
	}

	/**
	 * Make the given method accessible, explicitly setting it accessible if necessary.
	 * The <code>setAccessible(true)</code> method is only called when actually necessary,
	 * to avoid unnecessary conflicts with a JVM SecurityManager (if active).
	 * @param method the method to make accessible
	 * @see java.lang.reflect.Method#setAccessible
	 */
	public static void makeAccessible(Method method) {
		if (!Modifier.isPublic(method.getModifiers()) ||
				!Modifier.isPublic(method.getDeclaringClass().getModifiers())) {
			method.setAccessible(true);
		}
	}

	/**
	 * Make the given constructor accessible, explicitly setting it accessible if necessary.
	 * The <code>setAccessible(true)</code> method is only called when actually necessary,
	 * to avoid unnecessary conflicts with a JVM SecurityManager (if active).
	 * @param ctor the constructor to make accessible
	 * @see java.lang.reflect.Constructor#setAccessible
	 */
	public static void makeAccessible(Constructor ctor) {
		if (!Modifier.isPublic(ctor.getModifiers()) ||
				!Modifier.isPublic(ctor.getDeclaringClass().getModifiers())) {
			ctor.setAccessible(true);
		}
	}


	/**
	 * Perform the given callback operation on all matching methods of the
	 * given class and superclasses.
	 * <p>The same named method occurring on subclass and superclass will
	 * appear twice, unless excluded by a {@link MethodFilter}.
	 * @param targetClass class to start looking at
	 * @param mc the callback to invoke for each method
	 * @see #doWithMethods(Class, MethodCallback, MethodFilter)
	 */
	public static void doWithMethods(Class targetClass, MethodCallback mc) throws IllegalArgumentException {
		doWithMethods(targetClass, mc, null);
	}

	/**
	 * Perform the given callback operation on all matching methods of the
	 * given class and superclasses.
	 * <p>The same named method occurring on subclass and superclass will
	 * appear twice, unless excluded by the specified {@link MethodFilter}.
	 * @param targetClass class to start looking at
	 * @param mc the callback to invoke for each method
	 * @param mf the filter that determines the methods to apply the callback to
	 */
	public static void doWithMethods(Class targetClass, MethodCallback mc, MethodFilter mf)
			throws IllegalArgumentException {

		// Keep backing up the inheritance hierarchy.
		do {
			Method[] methods = targetClass.getDeclaredMethods();
			for (int i = 0; i < methods.length; i++) {
				if (mf != null && !mf.matches(methods[i])) {
					continue;
				}
				try {
					mc.doWith(methods[i]);
				}
				catch (IllegalAccessException ex) {
					throw new IllegalStateException(
							"Shouldn't be illegal to access method '" + methods[i].getName() + "': " + ex);
				}
			}
			targetClass = targetClass.getSuperclass();
		}
		while (targetClass != null);
	}

	/**
	 * Get all declared methods on the leaf class and all superclasses.
	 * Leaf class methods are included first.
	 */
	public static Method[] getAllDeclaredMethods(Class leafClass) throws IllegalArgumentException {
		final List list = new ArrayList(32);
		doWithMethods(leafClass, new MethodCallback() {
			public void doWith(Method method) {
				list.add(method);
			}
		});
		return (Method[]) list.toArray(new Method[list.size()]);
	}


	/**
	 * Invoke the given callback on all fields in the target class,
	 * going up the class hierarchy to get all declared fields.
	 * @param targetClass the target class to analyze
	 * @param fc the callback to invoke for each field
	 */
	public static void doWithFields(Class targetClass, FieldCallback fc) throws IllegalArgumentException {
		doWithFields(targetClass, fc, null);
	}

	/**
	 * Invoke the given callback on all fields in the target class,
	 * going up the class hierarchy to get all declared fields.
	 * @param targetClass the target class to analyze
	 * @param fc the callback to invoke for each field
	 * @param ff the filter that determines the fields to apply the callback to
	 */
	public static void doWithFields(Class targetClass, FieldCallback fc, FieldFilter ff)
			throws IllegalArgumentException {

		// Keep backing up the inheritance hierarchy.
		do {
			// Copy each field declared on this class unless it's static or file.
			Field[] fields = targetClass.getDeclaredFields();
			for (int i = 0; i < fields.length; i++) {
				// Skip static and final fields.
				if (ff != null && !ff.matches(fields[i])) {
					continue;
				}
				try {
					fc.doWith(fields[i]);
				}
				catch (IllegalAccessException ex) {
					throw new IllegalStateException(
							"Shouldn't be illegal to access field '" + fields[i].getName() + "': " + ex);
				}
			}
			targetClass = targetClass.getSuperclass();
		}
		while (targetClass != null && targetClass != Object.class);
	}

	/**
	 * Given the source object and the destination, which must be the same class
	 * or a subclass, copy all fields, including inherited fields. Designed to
	 * work on objects with public no-arg constructors.
	 * @throws IllegalArgumentException if the arguments are incompatible
	 */
	public static void shallowCopyFieldState(final Object src, final Object dest) throws IllegalArgumentException {
		if (src == null) {
			throw new IllegalArgumentException("Source for field copy cannot be null");
		}
		if (dest == null) {
			throw new IllegalArgumentException("Destination for field copy cannot be null");
		}
		if (!src.getClass().isAssignableFrom(dest.getClass())) {
			throw new IllegalArgumentException("Destination class [" + dest.getClass().getName() +
					"] must be same or subclass as source class [" + src.getClass().getName() + "]");
		}
		doWithFields(src.getClass(), new FieldCallback() {
			public void doWith(Field field) throws IllegalArgumentException, IllegalAccessException {
				makeAccessible(field);
				Object srcValue = field.get(src);
				field.set(dest, srcValue);
			}
		}, COPYABLE_FIELDS);
	}


	/**
	 * Action to take on each method.
	 */
	public static interface MethodCallback {

		/**
		 * Perform an operation using the given method.
		 * @param method the method to operate on
		 */
		void doWith(Method method) throws IllegalArgumentException, IllegalAccessException;
	}


	/**
	 * Callback optionally used to method fields to be operated on by a method callback.
	 */
	public static interface MethodFilter {

		/**
		 * Determine whether the given method matches.
		 * @param method the method to check
		 */
		boolean matches(Method method);
	}


	/**
	 * Callback interface invoked on each field in the hierarchy.
	 */
	public static interface FieldCallback {

		/**
		 * Perform an operation using the given field.
		 * @param field the field to operate on
		 */
		void doWith(Field field) throws IllegalArgumentException, IllegalAccessException;
	}


	/**
	 * Callback optionally used to filter fields to be operated on by a field callback.
	 */
	public static interface FieldFilter {

		/**
		 * Determine whether the given field matches.
		 * @param field the field to check
		 */
		boolean matches(Field field);
	}


	/**
	 * Pre-built FieldFilter that matches all non-static, non-final fields.
	 */
	public static FieldFilter COPYABLE_FIELDS = new FieldFilter() {
		public boolean matches(Field field) {
			return !(Modifier.isStatic(field.getModifiers()) ||
					Modifier.isFinal(field.getModifiers()));
		}
	};

}