Save This Page
Home » openjdk-7 » java » lang » reflect » [javadoc | source]
java.lang.reflect
public final class: Method [javadoc | source]
java.lang.Object
   java.lang.reflect.AccessibleObject
      java.lang.reflect.Method

All Implemented Interfaces:
    GenericDeclaration, Member, AnnotatedElement

A {@code Method} provides information about, and access to, a single method on a class or interface. The reflected method may be a class method or an instance method (including an abstract method).

A {@code Method} permits widening conversions to occur when matching the actual parameters to invoke with the underlying method's formal parameters, but it throws an {@code IllegalArgumentException} if a narrowing conversion would occur.

Fields inherited from java.lang.reflect.AccessibleObject:
override,  reflectionFactory,  securityCheckCache
Constructor:
 Method(Class<?> declaringClass,
    String name,
    Class<?>[] parameterTypes,
    Class<?> returnType,
    Class<?>[] checkedExceptions,
    int modifiers,
    int slot,
    String signature,
    byte[] annotations,
    byte[] parameterAnnotations,
    byte[] annotationDefault) 
    Package-private constructor used by ReflectAccess to enable instantiation of these objects in Java code from the java.lang package via sun.reflect.LangReflectAccess.
Method from java.lang.reflect.Method Summary:
copy,   equals,   getAnnotation,   getDeclaredAnnotations,   getDeclaringClass,   getDefaultValue,   getExceptionTypes,   getGenericExceptionTypes,   getGenericParameterTypes,   getGenericReturnType,   getMethodAccessor,   getModifiers,   getName,   getParameterAnnotations,   getParameterTypes,   getReturnType,   getTypeParameters,   hashCode,   invoke,   isBridge,   isSynthetic,   isVarArgs,   setMethodAccessor,   toGenericString,   toString
Methods from java.lang.reflect.AccessibleObject:
checkAccess,   getAnnotation,   getAnnotations,   getDeclaredAnnotations,   isAccessible,   isAnnotationPresent,   setAccessible,   setAccessible,   slowCheckMemberAccess
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.lang.reflect.Method Detail:
 Method copy() 
    Package-private routine (exposed to java.lang.Class via ReflectAccess) which returns a copy of this Method. The copy's "root" field points to this Method.
 public boolean equals(Object obj) 
    Compares this {@code Method} against the specified object. Returns true if the objects are the same. Two {@code Methods} are the same if they were declared by the same class and have the same name and formal parameter types and return type.
 public T getAnnotation(Class<T> annotationClass) 
 public Annotation[] getDeclaredAnnotations() 
 public Class<?> getDeclaringClass() 
    Returns the {@code Class} object representing the class or interface that declares the method represented by this {@code Method} object.
 public Object getDefaultValue() 
    Returns the default value for the annotation member represented by this {@code Method} instance. If the member is of a primitive type, an instance of the corresponding wrapper type is returned. Returns null if no default is associated with the member, or if the method instance does not represent a declared member of an annotation type.
 public Class<?>[] getExceptionTypes() 
    Returns an array of {@code Class} objects that represent the types of the exceptions declared to be thrown by the underlying method represented by this {@code Method} object. Returns an array of length 0 if the method declares no exceptions in its {@code throws} clause.
 public Type[] getGenericExceptionTypes() 
    Returns an array of {@code Type} objects that represent the exceptions declared to be thrown by this {@code Method} object. Returns an array of length 0 if the underlying method declares no exceptions in its {@code throws} clause.

    If an exception type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.

 public Type[] getGenericParameterTypes() 
    Returns an array of {@code Type} objects that represent the formal parameter types, in declaration order, of the method represented by this {@code Method} object. Returns an array of length 0 if the underlying method takes no parameters.

    If a formal parameter type is a parameterized type, the {@code Type} object returned for it must accurately reflect the actual type parameters used in the source code.

    If a formal parameter type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.

 public Type getGenericReturnType() 
    Returns a {@code Type} object that represents the formal return type of the method represented by this {@code Method} object.

    If the return type is a parameterized type, the {@code Type} object returned must accurately reflect the actual type parameters used in the source code.

    If the return type is a type variable or a parameterized type, it is created. Otherwise, it is resolved.

 MethodAccessor getMethodAccessor() 
 public int getModifiers() 
    Returns the Java language modifiers for the method represented by this {@code Method} object, as an integer. The {@code Modifier} class should be used to decode the modifiers.
 public String getName() 
    Returns the name of the method represented by this {@code Method} object, as a {@code String}.
 public Annotation[][] getParameterAnnotations() 
    Returns an array of arrays that represent the annotations on the formal parameters, in declaration order, of the method represented by this {@code Method} object. (Returns an array of length zero if the underlying method is parameterless. If the method has one or more parameters, a nested array of length zero is returned for each parameter with no annotations.) The annotation objects contained in the returned arrays are serializable. The caller of this method is free to modify the returned arrays; it will have no effect on the arrays returned to other callers.
 public Class<?>[] getParameterTypes() 
    Returns an array of {@code Class} objects that represent the formal parameter types, in declaration order, of the method represented by this {@code Method} object. Returns an array of length 0 if the underlying method takes no parameters.
 public Class<?> getReturnType() 
    Returns a {@code Class} object that represents the formal return type of the method represented by this {@code Method} object.
 public TypeVariable<Method>[] getTypeParameters() 
    Returns an array of {@code TypeVariable} objects that represent the type variables declared by the generic declaration represented by this {@code GenericDeclaration} object, in declaration order. Returns an array of length 0 if the underlying generic declaration declares no type variables.
 public int hashCode() 
    Returns a hashcode for this {@code Method}. The hashcode is computed as the exclusive-or of the hashcodes for the underlying method's declaring class name and the method's name.
 public Object invoke(Object obj,
    Object args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException 
    Invokes the underlying method represented by this {@code Method} object, on the specified object with the specified parameters. Individual parameters are automatically unwrapped to match primitive formal parameters, and both primitive and reference parameters are subject to method invocation conversions as necessary.

    If the underlying method is static, then the specified {@code obj} argument is ignored. It may be null.

    If the number of formal parameters required by the underlying method is 0, the supplied {@code args} array may be of length 0 or null.

    If the underlying method is an instance method, it is invoked using dynamic method lookup as documented in The Java Language Specification, Second Edition, section 15.12.4.4; in particular, overriding based on the runtime type of the target object will occur.

    If the underlying method is static, the class that declared the method is initialized if it has not already been initialized.

    If the method completes normally, the value it returns is returned to the caller of invoke; if the value has a primitive type, it is first appropriately wrapped in an object. However, if the value has the type of an array of a primitive type, the elements of the array are not wrapped in objects; in other words, an array of primitive type is returned. If the underlying method return type is void, the invocation returns null.

 public boolean isBridge() 
    Returns {@code true} if this method is a bridge method; returns {@code false} otherwise.
 public boolean isSynthetic() 
    Returns {@code true} if this method is a synthetic method; returns {@code false} otherwise.
 public boolean isVarArgs() 
    Returns {@code true} if this method was declared to take a variable number of arguments; returns {@code false} otherwise.
  void setMethodAccessor(MethodAccessor accessor) 
 public String toGenericString() 
    Returns a string describing this {@code Method}, including type parameters. The string is formatted as the method access modifiers, if any, followed by an angle-bracketed comma-separated list of the method's type parameters, if any, followed by the method's generic return type, followed by a space, followed by the class declaring the method, followed by a period, followed by the method name, followed by a parenthesized, comma-separated list of the method's generic formal parameter types. If this method was declared to take a variable number of arguments, instead of denoting the last parameter as "Type[]", it is denoted as "Type...". A space is used to separate access modifiers from one another and from the type parameters or return type. If there are no type parameters, the type parameter list is elided; if the type parameter list is present, a space separates the list from the class name. If the method is declared to throw exceptions, the parameter list is followed by a space, followed by the word throws followed by a comma-separated list of the generic thrown exception types. If there are no type parameters, the type parameter list is elided.

    The access modifiers are placed in canonical order as specified by "The Java Language Specification". This is {@code public}, {@code protected} or {@code private} first, and then other modifiers in the following order: {@code abstract}, {@code static}, {@code final}, {@code synchronized}, {@code native}, {@code strictfp}.

 public String toString() 
    Returns a string describing this {@code Method}. The string is formatted as the method access modifiers, if any, followed by the method return type, followed by a space, followed by the class declaring the method, followed by a period, followed by the method name, followed by a parenthesized, comma-separated list of the method's formal parameter types. If the method throws checked exceptions, the parameter list is followed by a space, followed by the word throws followed by a comma-separated list of the thrown exception types. For example:
       public boolean java.lang.Object.equals(java.lang.Object)
    

    The access modifiers are placed in canonical order as specified by "The Java Language Specification". This is {@code public}, {@code protected} or {@code private} first, and then other modifiers in the following order: {@code abstract}, {@code static}, {@code final}, {@code synchronized}, {@code native}, {@code strictfp}.