java.lang.reflect.Field Maven / Gradle / Ivy
/*
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stub files, must be accompanied by this notice in its entirety.
This work corresponds to the API signatures of JSR 219: Foundation
Profile 1.1. In the event of a discrepency between this work and the
JSR 219 specification, which is available at
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*/
package java.lang.reflect;
/**
* 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 Member
* @see java.lang.Class
* @see java.lang.Class#getFields()
* @see java.lang.Class#getField(String)
* @see java.lang.Class#getDeclaredFields()
* @see java.lang.Class#getDeclaredField(String)
*
* @author Nakul Saraiya
*/
public final class Field extends AccessibleObject implements Member
{
/*
* This hidden constructor does not necessarily correspond to
* a constructor in the original source file -- it keeps javadoc
* from generating an inappropriate default constructor.
*/
private Field() { }
/**
* Returns the Class object representing the class or interface
* that declares the field represented by this Field object.
*/
public Class getDeclaringClass() {
return null;
}
/**
* Returns the name of the field represented by this Field object.
*/
public String getName() {
return null;
}
/**
* 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.
*
* @see Modifier
*/
public int getModifiers() {
return 0;
}
/**
* Returns a Class object that identifies the
* declared type for the field represented by this
* Field object.
*
* @return a Class object identifying the declared
* type of the field represented by this object
*/
public Class getType() {
return null;
}
/**
* 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.
*/
public boolean equals(Object obj) {
return false;
}
/**
* 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.
*/
public int hashCode() {
return 0;
}
/**
* 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.
*/
public String toString() {
return null;
}
/**
* 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.
*
* @param obj object from which the represented field's value is
* to be extracted
* @return the value of the represented field in object
* obj; primitive values are wrapped in an appropriate
* object before being returned
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception IllegalArgumentException if the specified object is not an
* instance of the class or interface declaring the underlying
* field (or a subclass or implementor thereof).
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
*/
public Object get(Object obj)
throws IllegalArgumentException, IllegalAccessException
{
return null;
}
/**
* Gets the value of a static or instance boolean field.
*
* @param obj the object to extract the boolean value
* from
* @return the value of the boolean field
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#get
*/
public boolean getBoolean(Object obj)
throws IllegalArgumentException, IllegalAccessException
{
return false;
}
/**
* Gets the value of a static or instance byte field.
*
* @param obj the object to extract the byte value
* from
* @return the value of the byte field
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#get
*/
public byte getByte(Object obj)
throws IllegalArgumentException, IllegalAccessException
{
return ' ';
}
/**
* 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.
*
* @param obj the object to extract the char value
* from
* @return the value of the field converted to type char
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#get
*/
public char getChar(Object obj)
throws IllegalArgumentException, IllegalAccessException
{
return ' ';
}
/**
* 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.
*
* @param obj the object to extract the short value
* from
* @return the value of the field converted to type short
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#get
*/
public short getShort(Object obj)
throws IllegalArgumentException, IllegalAccessException
{
return -1;
}
/**
* 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.
*
* @param obj the object to extract the int value
* from
* @return the value of the field converted to type int
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#get
*/
public int getInt(Object obj)
throws IllegalArgumentException, IllegalAccessException
{
return 0;
}
/**
* 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.
*
* @param obj the object to extract the long value
* from
* @return the value of the field converted to type long
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#get
*/
public long getLong(Object obj)
throws IllegalArgumentException, IllegalAccessException
{
return -1;
}
/**
* 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.
*
* @param obj the object to extract the float value
* from
* @return the value of the field converted to type float
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#get
*/
public float getFloat(Object obj)
throws IllegalArgumentException, IllegalAccessException
{
return 0.0f;
}
/**
* 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.
*
* @param obj the object to extract the double value
* from
* @return the value of the field converted to type double
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#get
*/
public double getDouble(Object obj)
throws IllegalArgumentException, IllegalAccessException
{
return 0.0d;
}
/**
* 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.
*
* @param obj the object whose field should be modified
* @param value the new value for the field of obj
* being modified
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
*/
public void set(Object obj, Object value)
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.
*
* @param obj the object whose field should be modified
* @param z the new value for the field of obj
* being modified
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#set
*/
public void setBoolean(Object obj, boolean z)
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.
*
* @param obj the object whose field should be modified
* @param b the new value for the field of obj
* being modified
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#set
*/
public void setByte(Object obj, byte b)
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.
*
* @param obj the object whose field should be modified
* @param c the new value for the field of obj
* being modified
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#set
*/
public void setChar(Object obj, char c)
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.
*
* @param obj the object whose field should be modified
* @param s the new value for the field of obj
* being modified
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#set
*/
public void setShort(Object obj, short s)
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.
*
* @param obj the object whose field should be modified
* @param i the new value for the field of obj
* being modified
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#set
*/
public void setInt(Object obj, int i)
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.
*
* @param obj the object whose field should be modified
* @param l the new value for the field of obj
* being modified
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#set
*/
public void setLong(Object obj, long l)
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.
*
* @param obj the object whose field should be modified
* @param f the new value for the field of obj
* being modified
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#set
*/
public void setFloat(Object obj, float f)
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.
*
* @param obj the object whose field should be modified
* @param d the new value for the field of obj
* being modified
*
* @exception IllegalAccessException if the underlying field
* is inaccessible.
* @exception 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.
* @exception NullPointerException if the specified object is null
* and the field is an instance field.
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails.
* @see Field#set
*/
public void setDouble(Object obj, double d)
throws IllegalArgumentException, IllegalAccessException
{ }
}