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first difference.
There are 10 differences.
is old.
is new.
java.lang.reflect
Class Field
java.lang.Object
java.lang.reflect.AccessibleObject
java.lang.reflect.Field
-
All Implemented Interfaces:
-
AnnotatedElement
Member
,
Member
-
public final class
Field
-
extends
AccessibleObject
-
implements
Member
A Field provides information about, and dynamic access to, a single field of a class or an interface. The reflected field may be a class (static) field or an instance field.
A Field permits widening conversions to occur during a get or set access operation, but throws an IllegalArgumentException if a narrowing conversion would occur.
-
See Also:
-
Member
,
Class
,
Class.getFields()
,
Class.getField(String)
,
Class.getDeclaredFields()
,
Class.getDeclaredField(String)
Method Summary
|
boolean |
equals
(
Object
obj)
Compares this Field against the specified object. |
Object
|
get
(
Object
obj)
Returns the value of the field represented by this Field, on the specified object. |
<T extends java.lang.annotation.Annotation>
T
|
|
getAnnotation
(
Class
<T> annotationClass)
Returns this element's annotation for the specified type if such an annotation is present, else null.
|
boolean |
getBoolean
(
Object
obj)
Gets the value of a static or instance boolean field. |
byte |
getByte
(
Object
obj)
Gets the value of a static or instance byte field. |
char |
getChar
(
Object
obj)
Gets the value of a static or instance field of type char or of another primitive type convertible to type char via a widening conversion. |
java.lang.annotation.Annotation[]
|
getDeclaredAnnotations
()
Returns all annotations that are directly present on this element.
|
Class
|
getDeclaringClass
()
Returns the Class object representing the class or interface that declares the field represented by this Field object. |
double |
getDouble
(
Object
obj)
Gets the value of a static or instance field of type double or of another primitive type convertible to type double via a widening conversion. |
float |
getFloat
(
Object
obj)
Gets the value of a static or instance field of type float or of another primitive type convertible to type float via a widening conversion. |
Type
|
getGenericType
()
Returns a
Type
object that represents the declared type for the field represented by this
Field
object.
|
int |
getInt
(
Object
obj)
Gets the value of a static or instance field of type int or of another primitive type convertible to type int via a widening conversion. |
long |
getLong
(
Object
obj)
Gets the value of a static or instance field of type long or of another primitive type convertible to type long via a widening conversion. |
int |
getModifiers
()
Returns the Java language modifiers for the field represented by this Field object, as an integer. |
String
|
getName
()
Returns the name of the field represented by this Field object. |
short |
getShort
(
Object
obj)
Gets the value of a static or instance field of type short or of another primitive type convertible to type short via a widening conversion. |
Class
|
getType
()
Returns a Class object that identifies the declared type for the field represented by this Field object. |
int |
hashCode
()
Returns a hashcode for this Field. |
boolean
|
isEnumConstant
()
Returns
true
if this field represents an element of an enumerated type; returns
false
otherwise.
|
boolean
|
isSynthetic
()
Returns
true
if this field is a synthetic field; returns
false
otherwise.
|
void |
set
(
Object
obj,
Object
value)
Sets the field represented by this Field object on the specified object argument to the specified new value. |
void |
setBoolean
(
Object
obj, boolean z)
Sets the value of a field as a boolean on the specified object. |
void |
setByte
(
Object
obj, byte b)
Sets the value of a field as a byte on the specified object. |
void |
setChar
(
Object
obj, char c)
Sets the value of a field as a char on the specified object. |
void |
setDouble
(
Object
obj, double d)
Sets the value of a field as a double on the specified object. |
void |
setFloat
(
Object
obj, float f)
Sets the value of a field as a float on the specified object. |
void |
setInt
(
Object
obj, int i)
Sets the value of a field as an int on the specified object. |
void |
setLong
(
Object
obj, long l)
Sets the value of a field as a long on the specified object. |
void |
setShort
(
Object
obj, short s)
Sets the value of a field as a short on the specified object. |
String
|
toString
()
Returns a string describing this Field. |
getDeclaringClass
public Class getDeclaringClass()
-
Returns the Class object representing the class or interface that declares the field represented by this Field object.
-
-
Specified by:
-
getDeclaringClass
in interface
Member
-
-
Returns:
-
an object representing the declaring class of the underlying member
getName
public String getName()
-
Returns the name of the field represented by this Field object.
-
-
Specified by:
-
getName
in interface
Member
-
-
Returns:
-
the simple name of the underlying member
getModifiers
public int getModifiers()
-
Returns the Java language modifiers for the field represented by this Field object, as an integer. The Modifier class should be used to decode the modifiers.
-
-
Specified by:
-
getModifiers
in interface
Member
-
-
Returns:
-
the Java language modifiers for the underlying member
-
See Also:
-
Modifier
isEnumConstant
public boolean isEnumConstant ()
-
Returns
true
if this field represents an element of an enumerated type; returns
false
otherwise.
-
-
-
Returns:
-
true
if and only if this field represents an element of an enumerated type.
-
Since:
-
1.5
isSynthetic
public boolean isSynthetic ()
-
Returns
true
if this field is a synthetic field; returns
false
otherwise.
-
-
Specified by:
-
isSynthetic
in interface
Member
-
-
Returns:
-
true if and only if this field is a synthetic field as defined by the Java Language Specification.
-
Since:
-
1.5
getType
public Class getType()
-
Returns a Class object that identifies the declared type for the field represented by this Field object.
-
-
-
Returns:
-
a Class object identifying the declared type of the field represented by this object
getGenericType
public TypegetGenericType ()
-
Returns a
Type
object that represents the declared type for the field represented by this
Field
object.
If the
Type
is a parameterized type, the
Type
object returned must accurately reflect the actual type parameters used in the source code.
If an the type of the underlying field is a type variable or a parameterized type, it is created. Otherwise, it is resolved.
-
-
-
Returns:
-
a
Type
object that represents the declared type for the field represented by this
Field
object
-
Throws:
-
GenericSignatureFormatError
- if the generic field signature does not conform to the format specified in the Java Virtual Machine Specification, 3rd edition
-
TypeNotPresentException
- if the generic type signature of the underlying field refers to a non-existent type declaration
-
MalformedParameterizedTypeException
- if the generic signature of the underlying field refers to a parameterized type that cannot be instantiated for any reason
-
Since:
-
1.5
equals
public boolean equals(Object obj)
-
Compares this Field against the specified object. Returns true if the objects are the same. Two Field objects are the same if they were declared by the same class and have the same name and type.
-
-
Overrides:
-
equals
in class
Object
-
-
Parameters:
-
obj - the reference object with which to compare.
-
Returns:
-
true if this object is the same as the obj argument; false otherwise.
-
See Also:
-
Object.hashCode()
,
Hashtable
hashCode
public int hashCode()
-
Returns a hashcode for this Field. This is computed as the exclusive-or of the hashcodes for the underlying field's declaring class name and its name.
-
-
Overrides:
-
hashCode
in class
Object
-
-
Returns:
-
a hash code value for this object.
-
See Also:
-
Object.equals(java.lang.Object)
,
Hashtable
toString
public String toString()
-
Returns a string describing this Field. The format is the access modifiers for the field, if any, followed by the field type, followed by a space, followed by the fully-qualified name of the class declaring the field, followed by a period, followed by the name of the field. For example:
public static final int java.lang.Thread.MIN_PRIORITY
private int java.io.FileDescriptor.fd
The modifiers are placed in canonical order as specified by "The Java Language Specification". This is
public
,
protected
or
private
first, and then other modifiers in the following order:
static
,
final
,
transient
,
volatile
.
-
-
Overrides:
-
toString
in class
Object
-
-
Returns:
-
a string representation of the object.
get
public Object get(Object obj)
throws IllegalArgumentException,
IllegalAccessException
-
Returns the value of the field represented by this Field, on the specified object. The value is automatically wrapped in an object if it has a primitive type.
The underlying field's value is obtained as follows:
If the underlying field is a static field, the obj argument is ignored; it may be null.
Otherwise, the underlying field is an instance field. If the specified obj argument is null, the method throws a NullPointerException. If the specified object is not an instance of the class or interface declaring the underlying field, the method throws an IllegalArgumentException.
If this Field object enforces Java language access control, and the underlying field is inaccessible, the method throws an IllegalAccessException. If the underlying field is static, the class that declared the field is initialized if it has not already been initialized.
Otherwise, the value is retrieved from the underlying instance or static field. If the field has a primitive type, the value is wrapped in an object before being returned, otherwise it is returned as is.
If the field is hidden in the type of obj, the field's value is obtained according to the preceding rules.
-
-
-
Parameters:
-
obj - object from which the represented field's value is to be extracted
-
Returns:
-
the value of the represented field in object
obj
; primitive values are wrapped in an appropriate object before being returned
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof).
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
getBoolean
public boolean getBoolean(Object obj)
throws IllegalArgumentException,
IllegalAccessException
-
Gets the value of a static or instance boolean field.
-
-
-
Parameters:
-
obj - the object to extract the boolean value from
-
Returns:
-
the value of the boolean field
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if the field value cannot be converted to the type boolean by a widening conversion.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
get(java.lang.Object)
getByte
public byte getByte(Object obj)
throws IllegalArgumentException,
IllegalAccessException
-
Gets the value of a static or instance byte field.
-
-
-
Parameters:
-
obj - the object to extract the byte value from
-
Returns:
-
the value of the byte field
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if the field value cannot be converted to the type byte by a widening conversion.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
get(java.lang.Object)
getChar
public char getChar(Object obj)
throws IllegalArgumentException,
IllegalAccessException
-
Gets the value of a static or instance field of type char or of another primitive type convertible to type char via a widening conversion.
-
-
-
Parameters:
-
obj - the object to extract the char value from
-
Returns:
-
the value of the field converted to type char
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if the field value cannot be converted to the type char by a widening conversion.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
get(java.lang.Object)
getShort
public short getShort(Object obj)
throws IllegalArgumentException,
IllegalAccessException
-
Gets the value of a static or instance field of type short or of another primitive type convertible to type short via a widening conversion.
-
-
-
Parameters:
-
obj - the object to extract the short value from
-
Returns:
-
the value of the field converted to type short
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if the field value cannot be converted to the type short by a widening conversion.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
get(java.lang.Object)
getInt
public int getInt(Object obj)
throws IllegalArgumentException,
IllegalAccessException
-
Gets the value of a static or instance field of type int or of another primitive type convertible to type int via a widening conversion.
-
-
-
Parameters:
-
obj - the object to extract the int value from
-
Returns:
-
the value of the field converted to type int
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if the field value cannot be converted to the type int by a widening conversion.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
get(java.lang.Object)
getLong
public long getLong(Object obj)
throws IllegalArgumentException,
IllegalAccessException
-
Gets the value of a static or instance field of type long or of another primitive type convertible to type long via a widening conversion.
-
-
-
Parameters:
-
obj - the object to extract the long value from
-
Returns:
-
the value of the field converted to type long
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if the field value cannot be converted to the type long by a widening conversion.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
get(java.lang.Object)
getFloat
public float getFloat(Object obj)
throws IllegalArgumentException,
IllegalAccessException
-
Gets the value of a static or instance field of type float or of another primitive type convertible to type float via a widening conversion.
-
-
-
Parameters:
-
obj - the object to extract the float value from
-
Returns:
-
the value of the field converted to type float
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if the field value cannot be converted to the type float by a widening conversion.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
get(java.lang.Object)
getDouble
public double getDouble(Object obj)
throws IllegalArgumentException,
IllegalAccessException
-
Gets the value of a static or instance field of type double or of another primitive type convertible to type double via a widening conversion.
-
-
-
Parameters:
-
obj - the object to extract the double value from
-
Returns:
-
the value of the field converted to type double
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if the field value cannot be converted to the type double by a widening conversion.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
get(java.lang.Object)
set
public void set(Object obj,
Object value)
throws IllegalArgumentException,
IllegalAccessException
-
Sets the field represented by this Field object on the specified object argument to the specified new value. The new value is automatically unwrapped if the underlying field has a primitive type.
The operation proceeds as follows:
If the underlying field is static, the obj argument is ignored; it may be null.
Otherwise the underlying field is an instance field. If the specified object argument is null, the method throws a NullPointerException. If the specified object argument is not an instance of the class or interface declaring the underlying field, the method throws an IllegalArgumentException.
If this Field object enforces Java language access control, and the underlying field is inaccessible, the method throws an IllegalAccessException.
If the underlying field is final, the method throws an IllegalAccessException.
If the underlying field is of a primitive type, an unwrapping conversion is attempted to convert the new value to a value of a primitive type. If this attempt fails, the method throws an IllegalArgumentException.
If, after possible unwrapping, the new value cannot be converted to the type of the underlying field by an identity or widening conversion, the method throws an IllegalArgumentException.
If the underlying field is static, the class that declared the field is initialized if it has not already been initialized.
The field is set to the possibly unwrapped and widened new value.
If the field is hidden in the type of obj, the field's value is set according to the preceding rules.
-
-
-
Parameters:
-
obj - the object whose field should be modified
-
value - the new value for the field of obj being modified
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
setBoolean
public void setBoolean(Object obj,
boolean z)
throws IllegalArgumentException,
IllegalAccessException
-
Sets the value of a field as a boolean on the specified object. This method is equivalent to set(obj, zObj), where zObj is a Boolean object and zObj.booleanValue() == z.
-
-
-
Parameters:
-
obj - the object whose field should be modified
-
z - the new value for the field of obj being modified
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
set(java.lang.Object, java.lang.Object)
setByte
public void setByte(Object obj,
byte b)
throws IllegalArgumentException,
IllegalAccessException
-
Sets the value of a field as a byte on the specified object. This method is equivalent to set(obj, bObj), where bObj is a Byte object and bObj.byteValue() == b.
-
-
-
Parameters:
-
obj - the object whose field should be modified
-
b - the new value for the field of obj being modified
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
set(java.lang.Object, java.lang.Object)
setChar
public void setChar(Object obj,
char c)
throws IllegalArgumentException,
IllegalAccessException
-
Sets the value of a field as a char on the specified object. This method is equivalent to set(obj, cObj), where cObj is a Character object and cObj.charValue() == c.
-
-
-
Parameters:
-
obj - the object whose field should be modified
-
c - the new value for the field of obj being modified
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
set(java.lang.Object, java.lang.Object)
setShort
public void setShort(Object obj,
short s)
throws IllegalArgumentException,
IllegalAccessException
-
Sets the value of a field as a short on the specified object. This method is equivalent to set(obj, sObj), where sObj is a Short object and sObj.shortValue() == s.
-
-
-
Parameters:
-
obj - the object whose field should be modified
-
s - the new value for the field of obj being modified
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
set(java.lang.Object, java.lang.Object)
setInt
public void setInt(Object obj,
int i)
throws IllegalArgumentException,
IllegalAccessException
-
Sets the value of a field as an int on the specified object. This method is equivalent to set(obj, iObj), where iObj is a Integer object and iObj.intValue() == i.
-
-
-
Parameters:
-
obj - the object whose field should be modified
-
i - the new value for the field of obj being modified
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
set(java.lang.Object, java.lang.Object)
setLong
public void setLong(Object obj,
long l)
throws IllegalArgumentException,
IllegalAccessException
-
Sets the value of a field as a long on the specified object. This method is equivalent to set(obj, lObj), where lObj is a Long object and lObj.longValue() == l.
-
-
-
Parameters:
-
obj - the object whose field should be modified
-
l - the new value for the field of obj being modified
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
set(java.lang.Object, java.lang.Object)
setFloat
public void setFloat(Object obj,
float f)
throws IllegalArgumentException,
IllegalAccessException
-
Sets the value of a field as a float on the specified object. This method is equivalent to set(obj, fObj), where fObj is a Float object and fObj.floatValue() == f.
-
-
-
Parameters:
-
obj - the object whose field should be modified
-
f - the new value for the field of obj being modified
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
set(java.lang.Object, java.lang.Object)
setDouble
public void setDouble(Object obj,
double d)
throws IllegalArgumentException,
IllegalAccessException
-
Sets the value of a field as a double on the specified object. This method is equivalent to set(obj, dObj), where dObj is a Double object and dObj.doubleValue() == d.
-
-
-
Parameters:
-
obj - the object whose field should be modified
-
d - the new value for the field of obj being modified
-
Throws:
-
IllegalAccessException
- if the underlying field is inaccessible.
-
IllegalArgumentException
- if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof), or if an unwrapping conversion fails.
-
NullPointerException
- if the specified object is null and the field is an instance field.
-
ExceptionInInitializerError
- if the initialization provoked by this method fails.
-
See Also:
-
set(java.lang.Object, java.lang.Object)
getAnnotation
public <T extends java.lang.annotation.Annotation> T getAnnotation ( Class<T> annotationClass)
-
Description copied from interface:
AnnotatedElement
-
Returns this element's annotation for the specified type if such an annotation is present, else null.
-
-
Specified by:
-
getAnnotation
in interface
AnnotatedElement
-
Overrides:
-
getAnnotation
in class
AccessibleObject
-
-
Parameters:
-
annotationClass - the Class object corresponding to the annotation type
-
Returns:
-
this element's annotation for the specified annotation type if present on this element, else null
getDeclaredAnnotations
public java.lang.annotation.Annotation[] getDeclaredAnnotations ()
-
Description copied from interface:
AnnotatedElement
-
Returns all annotations that are directly present on this element. Unlike the other methods in this interface, this method ignores inherited annotations. (Returns an array of length zero if no annotations are directly present on this element.)
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Specified by:
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getDeclaredAnnotations
in interface
AnnotatedElement
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Overrides:
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getDeclaredAnnotations
in class
AccessibleObject
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Returns:
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All annotations directly present on this element