org.springframework.util
Class ReflectionUtils

java.lang.Object
  extended by org.springframework.util.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

Nested Class Summary
static interface ReflectionUtils.FieldCallback
          Callback interface invoked on each field in the hierarchy.
static interface ReflectionUtils.FieldFilter
          Callback optionally used to filter fields to be operated on by a field callback.
static interface ReflectionUtils.MethodCallback
          Action to take on each method.
static interface ReflectionUtils.MethodFilter
          Callback optionally used to method fields to be operated on by a method callback.
 
Field Summary
static ReflectionUtils.FieldFilter COPYABLE_FIELDS
          Pre-built FieldFilter that matches all non-static, non-final fields.
 
Constructor Summary
ReflectionUtils()
           
 
Method Summary
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.
static void doWithFields(Class<?> targetClass, ReflectionUtils.FieldCallback fc)
          Invoke the given callback on all fields in the target class, going up the class hierarchy to get all declared fields.
static void doWithFields(Class<?> targetClass, ReflectionUtils.FieldCallback fc, ReflectionUtils.FieldFilter ff)
          Invoke the given callback on all fields in the target class, going up the class hierarchy to get all declared fields.
static void doWithMethods(Class<?> targetClass, ReflectionUtils.MethodCallback mc)
          Perform the given callback operation on all matching methods of the given class and superclasses.
static void doWithMethods(Class<?> targetClass, ReflectionUtils.MethodCallback mc, ReflectionUtils.MethodFilter mf)
          Perform the given callback operation on all matching methods of the given class and superclasses.
static Field findField(Class<?> clazz, String name)
          Attempt to find a field on the supplied Class with the supplied name.
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.
static Method findMethod(Class<?> clazz, String name)
          Attempt to find a Method on the supplied class with the supplied name and no parameters.
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.
static Method[] getAllDeclaredMethods(Class<?> leafClass)
          Get all declared methods on the leaf class and all superclasses.
static Object getField(Field field, Object target)
          Get the field represented by the supplied field object on the specified target object.
static void handleInvocationTargetException(InvocationTargetException ex)
          Handle the given invocation target exception.
static void handleReflectionException(Exception ex)
          Handle the given reflection exception.
static Object invokeJdbcMethod(Method method, Object target)
          Invoke the specified JDBC API Method against the supplied target object with no arguments.
static Object invokeJdbcMethod(Method method, Object target, Object... args)
          Invoke the specified JDBC API Method against the supplied target object with the supplied arguments.
static Object invokeMethod(Method method, Object target)
          Invoke the specified Method against the supplied target object with no arguments.
static Object invokeMethod(Method method, Object target, Object... args)
          Invoke the specified Method against the supplied target object with the supplied arguments.
static boolean isEqualsMethod(Method method)
          Determine whether the given method is an "equals" method.
static boolean isHashCodeMethod(Method method)
          Determine whether the given method is a "hashCode" method.
static boolean isPublicStaticFinal(Field field)
          Determine whether the given field is a "public static final" constant.
static boolean isToStringMethod(Method method)
          Determine whether the given method is a "toString" method.
static void makeAccessible(Constructor<?> ctor)
          Make the given constructor accessible, explicitly setting it accessible if necessary.
static void makeAccessible(Field field)
          Make the given field accessible, explicitly setting it accessible if necessary.
static void makeAccessible(Method method)
          Make the given method accessible, explicitly setting it accessible if necessary.
static void rethrowException(Throwable ex)
          Rethrow the given exception, which is presumably the target exception of an InvocationTargetException.
static void rethrowRuntimeException(Throwable ex)
          Rethrow the given exception, which is presumably the target exception of an InvocationTargetException.
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.
static void shallowCopyFieldState(Object src, Object dest)
          Given the source object and the destination, which must be the same class or a subclass, copy all fields, including inherited fields.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

COPYABLE_FIELDS

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

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)
Invoke the specified Method against the supplied target object with no 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
Returns:
the invocation result, if any
See Also:
invokeMethod(java.lang.reflect.Method, Object, Object[])

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

invokeJdbcMethod

public static Object invokeJdbcMethod(Method method,
                                      Object target)
                               throws SQLException
Invoke the specified JDBC API Method against the supplied target object with no arguments.

Parameters:
method - the method to invoke
target - the target object to invoke the method on
Returns:
the invocation result, if any
Throws:
SQLException - the JDBC API SQLException to rethrow (if any)
See Also:
invokeJdbcMethod(java.lang.reflect.Method, Object, Object[])

invokeJdbcMethod

public static Object invokeJdbcMethod(Method method,
                                      Object target,
                                      Object... args)
                               throws SQLException
Invoke the specified JDBC API Method against the supplied target object with the supplied arguments.

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
Throws:
SQLException - the JDBC API SQLException to rethrow (if any)
See Also:
invokeMethod(java.lang.reflect.Method, Object, Object[])

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

rethrowRuntimeException

public static void rethrowRuntimeException(Throwable ex)
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 RuntimeException or Error if appropriate; otherwise, throws an IllegalStateException.

Parameters:
ex - the exception to rethrow
Throws:
RuntimeException - the rethrown exception

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()

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)

doWithMethods

public static void doWithMethods(Class<?> targetClass,
                                 ReflectionUtils.MethodCallback mc)
                          throws IllegalArgumentException
Perform the given callback operation on all matching methods of the given class and superclasses.

The same named method occurring on subclass and superclass will appear twice, unless excluded by a ReflectionUtils.MethodFilter.

Parameters:
targetClass - class to start looking at
mc - the callback to invoke for each method
Throws:
IllegalArgumentException
See Also:
doWithMethods(Class, MethodCallback, MethodFilter)

doWithMethods

public static void doWithMethods(Class<?> targetClass,
                                 ReflectionUtils.MethodCallback mc,
                                 ReflectionUtils.MethodFilter mf)
                          throws IllegalArgumentException
Perform the given callback operation on all matching methods of the given class and superclasses.

The same named method occurring on subclass and superclass will appear twice, unless excluded by the specified ReflectionUtils.MethodFilter.

Parameters:
targetClass - class to start looking at
mc - the callback to invoke for each method
mf - the filter that determines the methods to apply the callback to
Throws:
IllegalArgumentException

getAllDeclaredMethods

public static Method[] getAllDeclaredMethods(Class<?> leafClass)
                                      throws IllegalArgumentException
Get all declared methods on the leaf class and all superclasses. Leaf class methods are included first.

Throws:
IllegalArgumentException

doWithFields

public static void doWithFields(Class<?> targetClass,
                                ReflectionUtils.FieldCallback fc)
                         throws IllegalArgumentException
Invoke the given callback on all fields in the target class, going up the class hierarchy to get all declared fields.

Parameters:
targetClass - the target class to analyze
fc - the callback to invoke for each field
Throws:
IllegalArgumentException

doWithFields

public static void doWithFields(Class<?> targetClass,
                                ReflectionUtils.FieldCallback fc,
                                ReflectionUtils.FieldFilter ff)
                         throws IllegalArgumentException
Invoke the given callback on all fields in the target class, going up the class hierarchy to get all declared fields.

Parameters:
targetClass - the target class to analyze
fc - the callback to invoke for each field
ff - the filter that determines the fields to apply the callback to
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