org.springframework.util

Class ReflectionUtils


  • public abstract class ReflectionUtils
    extends Object
    Simple utility class for working with the reflection API and handling reflection exceptions.

    Only intended for internal use.

    Since:
    1.2.2
    Author:
    Juergen Hoeller, Rob Harrop, Rod Johnson, Costin Leau, Sam Brannen, Chris Beams
    • Field Detail

      • COPYABLE_FIELDS

        public static ReflectionUtils.FieldFilter COPYABLE_FIELDS
        Pre-built FieldFilter that matches all non-static, non-final fields.
      • NON_BRIDGED_METHODS

        public static ReflectionUtils.MethodFilter NON_BRIDGED_METHODS
        Pre-built MethodFilter that matches all non-bridge methods.
      • USER_DECLARED_METHODS

        public static ReflectionUtils.MethodFilter USER_DECLARED_METHODS
        Pre-built MethodFilter that matches all non-bridge methods which are not declared on java.lang.Object.
    • Constructor Detail

      • ReflectionUtils

        public ReflectionUtils()
    • Method Detail

      • findField

        public static Field findField(Class<?> clazz,
                      String name)
        Attempt to find a field on the supplied Class with the supplied name. Searches all superclasses up to Object.
        Parameters:
        clazz - the class to introspect
        name - the name of the field
        Returns:
        the corresponding Field object, or null if not found
      • findField

        public static Field findField(Class<?> clazz,
                      String name,
                      Class<?> type)
        Attempt to find a field on the supplied Class with the supplied name and/or type. Searches all superclasses up to Object.
        Parameters:
        clazz - the class to introspect
        name - the name of the field (may be null if type is specified)
        type - the type of the field (may be null if name is specified)
        Returns:
        the corresponding Field object, or null if not found
      • setField

        public static void setField(Field field,
                    Object target,
                    Object value)
        Set the field represented by the supplied field object on the specified target object to the specified value. In accordance with Field.set(Object, Object) semantics, the new value is automatically unwrapped if the underlying field has a primitive type.

        Thrown exceptions are handled via a call to handleReflectionException(Exception).

        Parameters:
        field - the field to set
        target - the target object on which to set the field
        value - the value to set; may be null
      • getField

        public static Object getField(Field field,
                      Object target)
        Get the field represented by the supplied field object on the specified target object. In accordance with Field.get(Object) semantics, the returned value is automatically wrapped if the underlying field has a primitive type.

        Thrown exceptions are handled via a call to handleReflectionException(Exception).

        Parameters:
        field - the field to get
        target - the target object from which to get the field
        Returns:
        the field's current value
      • findMethod

        public static Method findMethod(Class<?> clazz,
                        String name)
        Attempt to find a Method on the supplied class with the supplied name and no parameters. Searches all superclasses up to Object.

        Returns null if no Method can be found.

        Parameters:
        clazz - the class to introspect
        name - the name of the method
        Returns:
        the Method object, or null if none found
      • findMethod

        public static Method findMethod(Class<?> clazz,
                        String name,
                        Class<?>... paramTypes)
        Attempt to find a Method on the supplied class with the supplied name and parameter types. Searches all superclasses up to Object.

        Returns null if no Method can be found.

        Parameters:
        clazz - the class to introspect
        name - the name of the method
        paramTypes - the parameter types of the method (may be null to indicate any signature)
        Returns:
        the Method object, or null if none found
      • invokeMethod

        public static Object invokeMethod(Method method,
                          Object target,
                          Object... args)
        Invoke the specified Method against the supplied target object with the supplied arguments. The target object can be null when invoking a static Method.

        Thrown exceptions are handled via a call to handleReflectionException(java.lang.Exception).

        Parameters:
        method - the method to invoke
        target - the target object to invoke the method on
        args - the invocation arguments (may be null)
        Returns:
        the invocation result, if any
      • handleReflectionException

        public static void handleReflectionException(Exception ex)
        Handle the given reflection exception. Should only be called if no checked exception is expected to be thrown by the target method.

        Throws the underlying RuntimeException or Error in case of an InvocationTargetException with such a root cause. Throws an IllegalStateException with an appropriate message else.

        Parameters:
        ex - the reflection exception to handle
      • handleInvocationTargetException

        public static void handleInvocationTargetException(InvocationTargetException ex)
        Handle the given invocation target exception. Should only be called if no checked exception is expected to be thrown by the target method.

        Throws the underlying RuntimeException or Error in case of such a root cause. Throws an IllegalStateException else.

        Parameters:
        ex - the invocation target exception to handle
      • rethrowException

        public static void rethrowException(Throwable ex)
                                     throws Exception
        Rethrow the given exception, which is presumably the target exception of an InvocationTargetException. Should only be called if no checked exception is expected to be thrown by the target method.

        Rethrows the underlying exception cast to an Exception or Error if appropriate; otherwise, throws an IllegalStateException.

        Parameters:
        ex - the exception to rethrow
        Throws:
        Exception - the rethrown exception (in case of a checked exception)
      • declaresException

        public static boolean declaresException(Method method,
                                Class<?> exceptionType)
        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.
        Parameters:
        method - the declaring method
        exceptionType - the exception to throw
        Returns:
        true if the exception can be thrown as-is; false if it needs to be wrapped
      • isPublicStaticFinal

        public static boolean isPublicStaticFinal(Field field)
        Determine whether the given field is a "public static final" constant.
        Parameters:
        field - the field to check
      • isEqualsMethod

        public static boolean isEqualsMethod(Method method)
        Determine whether the given method is an "equals" method.
        See Also:
        Object.equals(Object)
      • isHashCodeMethod

        public static boolean isHashCodeMethod(Method method)
        Determine whether the given method is a "hashCode" method.
        See Also:
        Object.hashCode()
      • isToStringMethod

        public static boolean isToStringMethod(Method method)
        Determine whether the given method is a "toString" method.
        See Also:
        Object.toString()
      • isObjectMethod

        public static boolean isObjectMethod(Method method)
        Determine whether the given method is originally declared by Object.
      • isCglibRenamedMethod

        public static boolean isCglibRenamedMethod(Method renamedMethod)
        Determine whether the given method is a CGLIB 'renamed' method, following the pattern "CGLIB$methodName$0".
        Parameters:
        renamedMethod - the method to check
        See Also:
        org.springframework.cglib.proxy.Enhancer#rename
      • makeAccessible

        public static void makeAccessible(Field field)
        Make the given field accessible, explicitly setting it accessible if necessary. The setAccessible(true) method is only called when actually necessary, to avoid unnecessary conflicts with a JVM SecurityManager (if active).
        Parameters:
        field - the field to make accessible
        See Also:
        AccessibleObject.setAccessible(java.lang.reflect.AccessibleObject[], boolean)
      • makeAccessible

        public static void makeAccessible(Method method)
        Make the given method accessible, explicitly setting it accessible if necessary. The setAccessible(true) method is only called when actually necessary, to avoid unnecessary conflicts with a JVM SecurityManager (if active).
        Parameters:
        method - the method to make accessible
        See Also:
        AccessibleObject.setAccessible(java.lang.reflect.AccessibleObject[], boolean)
      • makeAccessible

        public static void makeAccessible(Constructor<?> ctor)
        Make the given constructor accessible, explicitly setting it accessible if necessary. The setAccessible(true) method is only called when actually necessary, to avoid unnecessary conflicts with a JVM SecurityManager (if active).
        Parameters:
        ctor - the constructor to make accessible
        See Also:
        AccessibleObject.setAccessible(java.lang.reflect.AccessibleObject[], boolean)
      • getUniqueDeclaredMethods

        public static Method[] getUniqueDeclaredMethods(Class<?> leafClass)
                                                 throws IllegalArgumentException
        Get the unique set of declared methods on the leaf class and all superclasses. Leaf class methods are included first and while traversing the superclass hierarchy any methods found with signatures matching a method already included are filtered out.
        Throws:
        IllegalArgumentException
      • shallowCopyFieldState

        public static void shallowCopyFieldState(Object src,
                                 Object dest)
                                          throws IllegalArgumentException
        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