Package org.apache.commons.lang3.reflect

Class MethodUtils

  • public class MethodUtils
extends Object

    Utility reflection methods focused on Methods, originally from Commons BeanUtils. Differences from the BeanUtils version may be noted, especially where similar functionality already existed within Lang.

    Known Limitations

    Accessing Public Methods In A Default Access Superclass

    There is an issue when invoking public methods contained in a default access superclass on JREs prior to 1.4. Reflection locates these methods fine and correctly assigns them as public. However, an IllegalAccessException is thrown if the method is invoked.

    MethodUtils contains a workaround for this situation. It will attempt to call AccessibleObject.setAccessible(boolean) on this method. If this call succeeds, then the method can be invoked as normal. This call will only succeed when the application has sufficient security privileges. If this call fails then the method may fail.

    Since:
    2.5

    • Constructor Detail

      • MethodUtils

        public MethodUtils()

        MethodUtils instances should NOT be constructed in standard programming. Instead, the class should be used as MethodUtils.getAccessibleMethod(method).

        This constructor is public to permit tools that require a JavaBean instance to operate.

    • Method Detail

      • invokeMethod

        public static Object invokeMethod​(Object object,
                                  boolean forceAccess,
                                  String methodName,
                                  Object[] args,
                                  Class<?>[] parameterTypes)
                           throws NoSuchMethodException,
                                  IllegalAccessException,
                                  InvocationTargetException

        Invokes a named method whose parameter type matches the object type.

        This method supports calls to methods taking primitive parameters via passing in wrapping classes. So, for example, a Boolean object would match a boolean primitive.

        Parameters:
        object - invoke method on this object
        forceAccess - force access to invoke method even if it's not accessible
        methodName - get method with this name
        args - use these arguments - treat null as empty array
        parameterTypes - match these parameters - treat null as empty array
        Returns:
        The value returned by the invoked method
        Throws:
        NoSuchMethodException - if there is no such accessible method
        InvocationTargetException - wraps an exception thrown by the method invoked
        IllegalAccessException - if the requested method is not accessible via reflection
        Since:
        3.5

      • getAccessibleMethod

        public static Method getAccessibleMethod​(Class<?> cls,
                                         String methodName,
                                         Class<?>... parameterTypes)

        Returns an accessible method (that is, one that can be invoked via reflection) with given name and parameters. If no such method can be found, return null. This is just a convenience wrapper for getAccessibleMethod(Method).

        Parameters:
        cls - get method from this class
        methodName - get method with this name
        parameterTypes - with these parameters types
        Returns:
        The accessible method

      • getAccessibleMethod

        public static Method getAccessibleMethod​(Method method)

        Returns an accessible method (that is, one that can be invoked via reflection) that implements the specified Method. If no such method can be found, return null.

        Parameters:
        method - The method that we wish to call
        Returns:
        The accessible method

      • getMatchingAccessibleMethod

        public static Method getMatchingAccessibleMethod​(Class<?> cls,
                                                 String methodName,
                                                 Class<?>... parameterTypes)

        Finds an accessible method that matches the given name and has compatible parameters. Compatible parameters mean that every method parameter is assignable from the given parameters. In other words, it finds a method with the given name that will take the parameters given.

        This method is used by invokeMethod(Object object, String methodName, Object[] args, Class[] parameterTypes).

        This method can match primitive parameter by passing in wrapper classes. For example, a Boolean will match a primitive boolean parameter.

        Parameters:
        cls - find method in this class
        methodName - find method with this name
        parameterTypes - find method with most compatible parameters
        Returns:
        The accessible method

      • getMatchingMethod

        public static Method getMatchingMethod​(Class<?> cls,
                                       String methodName,
                                       Class<?>... parameterTypes)

        Retrieves a method whether or not it's accessible. If no such method can be found, return null.

        Parameters:
        cls - The class that will be subjected to the method search
        methodName - The method that we wish to call
        parameterTypes - Argument class types
        Returns:
        The method
        Since:
        3.5

      • getOverrideHierarchy

        public static Set<Method> getOverrideHierarchy​(Method method,
                                               ClassUtils.Interfaces interfacesBehavior)
        Gets the hierarchy of overridden methods down to result respecting generics.
        Parameters:
        method - lowest to consider
        interfacesBehavior - whether to search interfaces, null implies false
        Returns:
        Set<Method> in ascending order from sub- to superclass
        Throws:
        NullPointerException - if the specified method is null
        Since:
        3.2

      • getMethodsWithAnnotation

        public static Method[] getMethodsWithAnnotation​(Class<?> cls,
                                                Class<? extends Annotation> annotationCls)
        Gets all class level public methods of the given class that are annotated with the given annotation.
        Parameters:
        cls - the Class to query
        annotationCls - the Annotation that must be present on a method to be matched
        Returns:
        an array of Methods (possibly empty).
        Throws:
        NullPointerException - if the class or annotation are null
        Since:
        3.4

      • getMethodsListWithAnnotation

        public static List<Method> getMethodsListWithAnnotation​(Class<?> cls,
                                                        Class<? extends Annotation> annotationCls)
        Gets all class level public methods of the given class that are annotated with the given annotation.
        Parameters:
        cls - the Class to query
        annotationCls - the Annotation that must be present on a method to be matched
        Returns:
        a list of Methods (possibly empty).
        Throws:
        IllegalArgumentException - if the class or annotation are null
        Since:
        3.4

      • getMethodsWithAnnotation

        public static Method[] getMethodsWithAnnotation​(Class<?> cls,
                                                Class<? extends Annotation> annotationCls,
                                                boolean searchSupers,
                                                boolean ignoreAccess)
        Gets all methods of the given class that are annotated with the given annotation.
        Parameters:
        cls - the Class to query
        annotationCls - the Annotation that must be present on a method to be matched
        searchSupers - determines if a lookup in the entire inheritance hierarchy of the given class should be performed
        ignoreAccess - determines if non public methods should be considered
        Returns:
        an array of Methods (possibly empty).
        Throws:
        NullPointerException - if the class or annotation are null
        Since:
        3.6

      • getMethodsListWithAnnotation

        public static List<Method> getMethodsListWithAnnotation​(Class<?> cls,
                                                        Class<? extends Annotation> annotationCls,
                                                        boolean searchSupers,
                                                        boolean ignoreAccess)
        Gets all methods of the given class that are annotated with the given annotation.
        Parameters:
        cls - the Class to query
        annotationCls - the Annotation that must be present on a method to be matched
        searchSupers - determines if a lookup in the entire inheritance hierarchy of the given class should be performed
        ignoreAccess - determines if non public methods should be considered
        Returns:
        a list of Methods (possibly empty).
        Throws:
        NullPointerException - if either the class or annotation class is null
        Since:
        3.6

      • getAnnotation

        public static <A extends Annotation> A getAnnotation​(Method method,
                                                     Class<A> annotationCls,
                                                     boolean searchSupers,
                                                     boolean ignoreAccess)

        Gets the annotation object with the given annotation type that is present on the given method or optionally on any equivalent method in super classes and interfaces. Returns null if the annotation type was not present.

        Stops searching for an annotation once the first annotation of the specified type has been found. Additional annotations of the specified type will be silently ignored.

        Type Parameters:
        A - the annotation type
        Parameters:
        method - the Method to query
        annotationCls - the Annotation to check if is present on the method
        searchSupers - determines if a lookup in the entire inheritance hierarchy of the given class is performed if the annotation was not directly present
        ignoreAccess - determines if underlying method has to be accessible
        Returns:
        the first matching annotation, or null if not found
        Throws:
        NullPointerException - if either the method or annotation class is null
        Since:
        3.6