Class MethodUtils


  • public class MethodUtils
    extends java.lang.Object

    Utility reflection methods focused on methods in general rather than properties in particular.

    Known Limitations

    Accessing Public Methods In A Default Access Superclass

    There is an issue when invoking public methods contained in a default access superclass. 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 setAccessible 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 privilages. If this call fails then a warning will be logged and the method may fail.

    Version:
    $Id: MethodUtils.java 1746219 2016-05-31 05:05:09Z ggregory $
    • Constructor Summary

      Constructors 
      Constructor Description
      MethodUtils()  
    • Method Summary

      All Methods Static Methods Concrete Methods 
      Modifier and Type Method Description
      static int clearCache()
      Clear the method cache.
      static java.lang.reflect.Method getAccessibleMethod​(java.lang.Class<?> clazz, java.lang.reflect.Method method)
      Return an accessible method (that is, one that can be invoked via reflection) that implements the specified Method.
      static java.lang.reflect.Method getAccessibleMethod​(java.lang.Class<?> clazz, java.lang.String methodName, java.lang.Class<?> parameterType)
      Return an accessible method (that is, one that can be invoked via reflection) with given name and a single parameter.
      static java.lang.reflect.Method getAccessibleMethod​(java.lang.Class<?> clazz, java.lang.String methodName, java.lang.Class<?>[] parameterTypes)
      Return an accessible method (that is, one that can be invoked via reflection) with given name and parameters.
      static java.lang.reflect.Method getAccessibleMethod​(java.lang.reflect.Method method)
      Return an accessible method (that is, one that can be invoked via reflection) that implements the specified Method.
      static java.lang.reflect.Method getMatchingAccessibleMethod​(java.lang.Class<?> clazz, java.lang.String methodName, java.lang.Class<?>[] parameterTypes)
      Find an accessible method that matches the given name and has compatible parameters.
      static java.lang.Class<?> getPrimitiveType​(java.lang.Class<?> wrapperType)
      Gets the class for the primitive type corresponding to the primitive wrapper class given.
      static java.lang.Class<?> getPrimitiveWrapper​(java.lang.Class<?> primitiveType)
      Gets the wrapper object class for the given primitive type class.
      static java.lang.Object invokeExactMethod​(java.lang.Object object, java.lang.String methodName, java.lang.Object arg)
      Invoke a method whose parameter type matches exactly the object type.
      static java.lang.Object invokeExactMethod​(java.lang.Object object, java.lang.String methodName, java.lang.Object[] args)
      Invoke a method whose parameter types match exactly the object types.
      static java.lang.Object invokeExactMethod​(java.lang.Object object, java.lang.String methodName, java.lang.Object[] args, java.lang.Class<?>[] parameterTypes)
      Invoke a method whose parameter types match exactly the parameter types given.
      static java.lang.Object invokeExactStaticMethod​(java.lang.Class<?> objectClass, java.lang.String methodName, java.lang.Object arg)
      Invoke a static method whose parameter type matches exactly the object type.
      static java.lang.Object invokeExactStaticMethod​(java.lang.Class<?> objectClass, java.lang.String methodName, java.lang.Object[] args)
      Invoke a static method whose parameter types match exactly the object types.
      static java.lang.Object invokeExactStaticMethod​(java.lang.Class<?> objectClass, java.lang.String methodName, java.lang.Object[] args, java.lang.Class<?>[] parameterTypes)
      Invoke a static method whose parameter types match exactly the parameter types given.
      static java.lang.Object invokeMethod​(java.lang.Object object, java.lang.String methodName, java.lang.Object arg)
      Invoke a named method whose parameter type matches the object type.
      static java.lang.Object invokeMethod​(java.lang.Object object, java.lang.String methodName, java.lang.Object[] args)
      Invoke a named method whose parameter type matches the object type.
      static java.lang.Object invokeMethod​(java.lang.Object object, java.lang.String methodName, java.lang.Object[] args, java.lang.Class<?>[] parameterTypes)
      Invoke a named method whose parameter type matches the object type.
      static java.lang.Object invokeStaticMethod​(java.lang.Class<?> objectClass, java.lang.String methodName, java.lang.Object arg)
      Invoke a named static method whose parameter type matches the object type.
      static java.lang.Object invokeStaticMethod​(java.lang.Class<?> objectClass, java.lang.String methodName, java.lang.Object[] args)
      Invoke a named static method whose parameter type matches the object type.
      static java.lang.Object invokeStaticMethod​(java.lang.Class<?> objectClass, java.lang.String methodName, java.lang.Object[] args, java.lang.Class<?>[] parameterTypes)
      Invoke a named static method whose parameter type matches the object type.
      static boolean isAssignmentCompatible​(java.lang.Class<?> parameterType, java.lang.Class<?> parameterization)
      Determine whether a type can be used as a parameter in a method invocation.
      static void setCacheMethods​(boolean cacheMethods)
      Set whether methods should be cached for greater performance or not, default is true.
      static java.lang.Class<?> toNonPrimitiveClass​(java.lang.Class<?> clazz)
      Find a non primitive representation for given primitive class.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • MethodUtils

        public MethodUtils()
    • Method Detail

      • setCacheMethods

        public static void setCacheMethods​(boolean cacheMethods)
        Set whether methods should be cached for greater performance or not, default is true.
        Parameters:
        cacheMethods - true if methods should be cached for greater performance, otherwise false
        Since:
        1.8.0
      • clearCache

        public static int clearCache()
        Clear the method cache.
        Returns:
        the number of cached methods cleared
        Since:
        1.8.0
      • invokeMethod

        public static java.lang.Object invokeMethod​(java.lang.Object object,
                                                    java.lang.String methodName,
                                                    java.lang.Object arg)
                                             throws java.lang.NoSuchMethodException,
                                                    java.lang.IllegalAccessException,
                                                    java.lang.reflect.InvocationTargetException

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

        The behaviour of this method is less deterministic than invokeExactMethod(). It loops through all methods with names that match and then executes the first it finds with compatible parameters.

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

        This is a convenient wrapper for invokeMethod(Object object,String methodName,Object [] args).

        Parameters:
        object - invoke method on this object
        methodName - get method with this name
        arg - use this argument. May be null (this will result in calling the parameterless method with name methodName).
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
      • invokeMethod

        public static java.lang.Object invokeMethod​(java.lang.Object object,
                                                    java.lang.String methodName,
                                                    java.lang.Object[] args)
                                             throws java.lang.NoSuchMethodException,
                                                    java.lang.IllegalAccessException,
                                                    java.lang.reflect.InvocationTargetException

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

        The behaviour of this method is less deterministic than invokeExactMethod(Object object,String methodName,Object [] args). It loops through all methods with names that match and then executes the first it finds with compatible parameters.

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

        This is a convenient wrapper for invokeMethod(Object object,String methodName,Object [] args,Class[] parameterTypes).

        Parameters:
        object - invoke method on this object
        methodName - get method with this name
        args - use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
      • invokeMethod

        public static java.lang.Object invokeMethod​(java.lang.Object object,
                                                    java.lang.String methodName,
                                                    java.lang.Object[] args,
                                                    java.lang.Class<?>[] parameterTypes)
                                             throws java.lang.NoSuchMethodException,
                                                    java.lang.IllegalAccessException,
                                                    java.lang.reflect.InvocationTargetException

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

        The behaviour of this method is less deterministic than invokeExactMethod(Object object,String methodName,Object [] args,Class[] parameterTypes). It loops through all methods with names that match and then executes the first it finds with compatible parameters.

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

        Parameters:
        object - invoke method on this object
        methodName - get method with this name
        args - use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
        parameterTypes - match these parameters - treat null as empty array
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
      • invokeExactMethod

        public static java.lang.Object invokeExactMethod​(java.lang.Object object,
                                                         java.lang.String methodName,
                                                         java.lang.Object arg)
                                                  throws java.lang.NoSuchMethodException,
                                                         java.lang.IllegalAccessException,
                                                         java.lang.reflect.InvocationTargetException

        Invoke a method whose parameter type matches exactly the object type.

        This is a convenient wrapper for invokeExactMethod(Object object,String methodName,Object [] args).

        Parameters:
        object - invoke method on this object
        methodName - get method with this name
        arg - use this argument. May be null (this will result in calling the parameterless method with name methodName).
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
      • invokeExactMethod

        public static java.lang.Object invokeExactMethod​(java.lang.Object object,
                                                         java.lang.String methodName,
                                                         java.lang.Object[] args)
                                                  throws java.lang.NoSuchMethodException,
                                                         java.lang.IllegalAccessException,
                                                         java.lang.reflect.InvocationTargetException

        Invoke a method whose parameter types match exactly the object types.

        This uses reflection to invoke the method obtained from a call to getAccessibleMethod().

        Parameters:
        object - invoke method on this object
        methodName - get method with this name
        args - use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
      • invokeExactMethod

        public static java.lang.Object invokeExactMethod​(java.lang.Object object,
                                                         java.lang.String methodName,
                                                         java.lang.Object[] args,
                                                         java.lang.Class<?>[] parameterTypes)
                                                  throws java.lang.NoSuchMethodException,
                                                         java.lang.IllegalAccessException,
                                                         java.lang.reflect.InvocationTargetException

        Invoke a method whose parameter types match exactly the parameter types given.

        This uses reflection to invoke the method obtained from a call to getAccessibleMethod().

        Parameters:
        object - invoke method on this object
        methodName - get method with this name
        args - use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
        parameterTypes - match these parameters - treat null as empty array
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
      • invokeExactStaticMethod

        public static java.lang.Object invokeExactStaticMethod​(java.lang.Class<?> objectClass,
                                                               java.lang.String methodName,
                                                               java.lang.Object[] args,
                                                               java.lang.Class<?>[] parameterTypes)
                                                        throws java.lang.NoSuchMethodException,
                                                               java.lang.IllegalAccessException,
                                                               java.lang.reflect.InvocationTargetException

        Invoke a static method whose parameter types match exactly the parameter types given.

        This uses reflection to invoke the method obtained from a call to getAccessibleMethod(Class, String, Class[]).

        Parameters:
        objectClass - invoke static method on this class
        methodName - get method with this name
        args - use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
        parameterTypes - match these parameters - treat null as empty array
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
        Since:
        1.8.0
      • invokeStaticMethod

        public static java.lang.Object invokeStaticMethod​(java.lang.Class<?> objectClass,
                                                          java.lang.String methodName,
                                                          java.lang.Object arg)
                                                   throws java.lang.NoSuchMethodException,
                                                          java.lang.IllegalAccessException,
                                                          java.lang.reflect.InvocationTargetException

        Invoke a named static method whose parameter type matches the object type.

        The behaviour of this method is less deterministic than invokeExactMethod(Object, String, Object[], Class[]). It loops through all methods with names that match and then executes the first it finds with compatible parameters.

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

        This is a convenient wrapper for invokeStaticMethod(Class objectClass,String methodName,Object [] args).

        Parameters:
        objectClass - invoke static method on this class
        methodName - get method with this name
        arg - use this argument. May be null (this will result in calling the parameterless method with name methodName).
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
        Since:
        1.8.0
      • invokeStaticMethod

        public static java.lang.Object invokeStaticMethod​(java.lang.Class<?> objectClass,
                                                          java.lang.String methodName,
                                                          java.lang.Object[] args)
                                                   throws java.lang.NoSuchMethodException,
                                                          java.lang.IllegalAccessException,
                                                          java.lang.reflect.InvocationTargetException

        Invoke a named static method whose parameter type matches the object type.

        The behaviour of this method is less deterministic than invokeExactMethod(Object object,String methodName,Object [] args). It loops through all methods with names that match and then executes the first it finds with compatible parameters.

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

        This is a convenient wrapper for invokeStaticMethod(Class objectClass,String methodName,Object [] args,Class[] parameterTypes).

        Parameters:
        objectClass - invoke static method on this class
        methodName - get method with this name
        args - use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
        Since:
        1.8.0
      • invokeStaticMethod

        public static java.lang.Object invokeStaticMethod​(java.lang.Class<?> objectClass,
                                                          java.lang.String methodName,
                                                          java.lang.Object[] args,
                                                          java.lang.Class<?>[] parameterTypes)
                                                   throws java.lang.NoSuchMethodException,
                                                          java.lang.IllegalAccessException,
                                                          java.lang.reflect.InvocationTargetException

        Invoke a named static method whose parameter type matches the object type.

        The behaviour of this method is less deterministic than invokeExactStaticMethod(Class objectClass,String methodName,Object [] args,Class[] parameterTypes). It loops through all methods with names that match and then executes the first it finds with compatible parameters.

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

        Parameters:
        objectClass - invoke static method on this class
        methodName - get method with this name
        args - use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
        parameterTypes - match these parameters - treat null as empty array
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
        Since:
        1.8.0
      • invokeExactStaticMethod

        public static java.lang.Object invokeExactStaticMethod​(java.lang.Class<?> objectClass,
                                                               java.lang.String methodName,
                                                               java.lang.Object arg)
                                                        throws java.lang.NoSuchMethodException,
                                                               java.lang.IllegalAccessException,
                                                               java.lang.reflect.InvocationTargetException

        Invoke a static method whose parameter type matches exactly the object type.

        This is a convenient wrapper for invokeExactStaticMethod(Class objectClass,String methodName,Object [] args).

        Parameters:
        objectClass - invoke static method on this class
        methodName - get method with this name
        arg - use this argument. May be null (this will result in calling the parameterless method with name methodName).
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
        Since:
        1.8.0
      • invokeExactStaticMethod

        public static java.lang.Object invokeExactStaticMethod​(java.lang.Class<?> objectClass,
                                                               java.lang.String methodName,
                                                               java.lang.Object[] args)
                                                        throws java.lang.NoSuchMethodException,
                                                               java.lang.IllegalAccessException,
                                                               java.lang.reflect.InvocationTargetException

        Invoke a static method whose parameter types match exactly the object types.

        This uses reflection to invoke the method obtained from a call to getAccessibleMethod(Class, String, Class[]).

        Parameters:
        objectClass - invoke static method on this class
        methodName - get method with this name
        args - use these arguments - treat null as empty array (passing null will result in calling the parameterless method with name methodName).
        Returns:
        The value returned by the invoked method
        Throws:
        java.lang.NoSuchMethodException - if there is no such accessible method
        java.lang.reflect.InvocationTargetException - wraps an exception thrown by the method invoked
        java.lang.IllegalAccessException - if the requested method is not accessible via reflection
        Since:
        1.8.0
      • getAccessibleMethod

        public static java.lang.reflect.Method getAccessibleMethod​(java.lang.Class<?> clazz,
                                                                   java.lang.String methodName,
                                                                   java.lang.Class<?> parameterType)

        Return an accessible method (that is, one that can be invoked via reflection) with given name and a single parameter. If no such method can be found, return null. Basically, a convenience wrapper that constructs a Class array for you.

        Parameters:
        clazz - get method from this class
        methodName - get method with this name
        parameterType - taking this type of parameter
        Returns:
        The accessible method
      • getAccessibleMethod

        public static java.lang.reflect.Method getAccessibleMethod​(java.lang.Class<?> clazz,
                                                                   java.lang.String methodName,
                                                                   java.lang.Class<?>[] parameterTypes)

        Return 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 convenient wrapper for getAccessibleMethod(Method method).

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

        public static java.lang.reflect.Method getAccessibleMethod​(java.lang.reflect.Method method)

        Return 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
      • getAccessibleMethod

        public static java.lang.reflect.Method getAccessibleMethod​(java.lang.Class<?> clazz,
                                                                   java.lang.reflect.Method method)

        Return 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:
        clazz - The class of the object
        method - The method that we wish to call
        Returns:
        The accessible method
        Since:
        1.8.0
      • getMatchingAccessibleMethod

        public static java.lang.reflect.Method getMatchingAccessibleMethod​(java.lang.Class<?> clazz,
                                                                           java.lang.String methodName,
                                                                           java.lang.Class<?>[] parameterTypes)

        Find 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 slightly undeterministic since it loops through methods names and return the first matching method.

        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:
        clazz - find method in this class
        methodName - find method with this name
        parameterTypes - find method with compatible parameters
        Returns:
        The accessible method
      • isAssignmentCompatible

        public static final boolean isAssignmentCompatible​(java.lang.Class<?> parameterType,
                                                           java.lang.Class<?> parameterization)

        Determine whether a type can be used as a parameter in a method invocation. This method handles primitive conversions correctly.

        In order words, it will match a Boolean to a boolean, a Long to a long, a Float to a float, a Integer to a int, and a Double to a double. Now logic widening matches are allowed. For example, a Long will not match a int.

        Parameters:
        parameterType - the type of parameter accepted by the method
        parameterization - the type of parameter being tested
        Returns:
        true if the assignment is compatible.
      • getPrimitiveWrapper

        public static java.lang.Class<?> getPrimitiveWrapper​(java.lang.Class<?> primitiveType)
        Gets the wrapper object class for the given primitive type class. For example, passing boolean.class returns Boolean.class
        Parameters:
        primitiveType - the primitive type class for which a match is to be found
        Returns:
        the wrapper type associated with the given primitive or null if no match is found
      • getPrimitiveType

        public static java.lang.Class<?> getPrimitiveType​(java.lang.Class<?> wrapperType)
        Gets the class for the primitive type corresponding to the primitive wrapper class given. For example, an instance of Boolean.class returns a boolean.class.
        Parameters:
        wrapperType - the
        Returns:
        the primitive type class corresponding to the given wrapper class, null if no match is found
      • toNonPrimitiveClass

        public static java.lang.Class<?> toNonPrimitiveClass​(java.lang.Class<?> clazz)
        Find a non primitive representation for given primitive class.
        Parameters:
        clazz - the class to find a representation for, not null
        Returns:
        the original class if it not a primitive. Otherwise the wrapper class. Not null