com.cjcrafter.foliascheduler.util

Class FieldAccessor

java.lang.Object

com.cjcrafter.foliascheduler.util.FieldAccessor

public class FieldAccessor
extends java.lang.Object

A class that provides access to the Field class in the Java Reflection API.

This class provides methods to access the value of a field, set the value of a field without requiring a try-catch block. Any IllegalAccessException is caught and rethrown as a WrappedReflectiveOperationException.

Constructor Summary

Constructors

Constructor and Description
FieldAccessor(@NotNull java.lang.reflect.Field field)

Method Summary

Modifier and Type	Method and Description
@Nullable java.lang.Object	get(@Nullable java.lang.Object obj) Returns the value of the field represented by this Field, on the specified object.
boolean	getBoolean(@Nullable java.lang.Object obj) Gets the value of a static or instance boolean field.
byte	getByte(@Nullable java.lang.Object obj) Gets the value of a static or instance byte field.
char	getChar(@Nullable java.lang.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.
double	getDouble(@Nullable java.lang.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.
@NotNull java.lang.reflect.Field	getField() Returns the Field object that this FieldAccessor object represents.
float	getFloat(@Nullable java.lang.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.
int	getInt(@Nullable java.lang.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(@Nullable java.lang.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.
short	getShort(@Nullable java.lang.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.
void	set(@Nullable java.lang.Object obj, @Nullable java.lang.Object value) Sets the field represented by this Field object on the specified object argument to the specified new value.
void	setBoolean(@Nullable java.lang.Object obj, boolean z) Sets the value of a field as a boolean on the specified object.
void	setByte(@Nullable java.lang.Object obj, byte b) Sets the value of a field as a byte on the specified object.
void	setChar(@Nullable java.lang.Object obj, char c) Sets the value of a field as a char on the specified object.
void	setDouble(@Nullable java.lang.Object obj, double d) Sets the value of a field as a double on the specified object.
void	setFloat(@Nullable java.lang.Object obj, float f) Sets the value of a field as a float on the specified object.
void	setInt(@Nullable java.lang.Object obj, int i) Sets the value of a field as an int on the specified object.
void	setLong(@Nullable java.lang.Object obj, long l) Sets the value of a field as a long on the specified object.
void	setShort(@Nullable java.lang.Object obj, short s) Sets the value of a field as a short on the specified object.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FieldAccessor

public FieldAccessor(@NotNull
                     @NotNull java.lang.reflect.Field field)

Method Detail

getField

@NotNull
public @NotNull java.lang.reflect.Field getField()

Returns the Field object that this FieldAccessor object represents.

Returns:

the underlying Field object

getBoolean

public boolean getBoolean(@Nullable
                          @Nullable java.lang.Object obj)
                   throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is inaccessible.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.get(java.lang.Object)

get

@Nullable
public @Nullable java.lang.Object get(@Nullable
                                                @Nullable java.lang.Object obj)
                                         throws java.lang.IllegalArgumentException

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 is enforcing 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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is inaccessible.

java.lang.IllegalArgumentException - if the specified object is not an instance of the class or interface declaring the underlying field (or a subclass or implementor thereof).

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

set

public void set(@Nullable
                @Nullable java.lang.Object obj,
                @Nullable
                @Nullable java.lang.Object value)
         throws java.lang.IllegalArgumentException

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 is enforcing 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 unless setAccessible(true) has succeeded for this Field object and the field is non-static. Setting a final field in this way is meaningful only during deserialization or reconstruction of instances of classes with blank final fields, before they are made available for access by other parts of a program. Use in any other context may have unpredictable effects, including cases in which other parts of a program continue to use the original value of this field.

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

setFloat

public void setFloat(@Nullable
                     @Nullable java.lang.Object obj,
                     float f)
              throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.set(java.lang.Object, java.lang.Object)

getByte

public byte getByte(@Nullable
                    @Nullable java.lang.Object obj)
             throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is inaccessible.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.get(java.lang.Object)

setBoolean

public void setBoolean(@Nullable
                       @Nullable java.lang.Object obj,
                       boolean z)
                throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.set(java.lang.Object, java.lang.Object)

getChar

public char getChar(@Nullable
                    @Nullable java.lang.Object obj)
             throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is inaccessible.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.get(java.lang.Object)

setDouble

public void setDouble(@Nullable
                      @Nullable java.lang.Object obj,
                      double d)
               throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.set(java.lang.Object, java.lang.Object)

setByte

public void setByte(@Nullable
                    @Nullable java.lang.Object obj,
                    byte b)
             throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.set(java.lang.Object, java.lang.Object)

getShort

public short getShort(@Nullable
                      @Nullable java.lang.Object obj)
               throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is inaccessible.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.get(java.lang.Object)

setChar

public void setChar(@Nullable
                    @Nullable java.lang.Object obj,
                    char c)
             throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.set(java.lang.Object, java.lang.Object)

getInt

public int getInt(@Nullable
                  @Nullable java.lang.Object obj)
           throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is inaccessible.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.get(java.lang.Object)

getLong

public long getLong(@Nullable
                    @Nullable java.lang.Object obj)
             throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is inaccessible.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.get(java.lang.Object)

setShort

public void setShort(@Nullable
                     @Nullable java.lang.Object obj,
                     short s)
              throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.set(java.lang.Object, java.lang.Object)

setInt

public void setInt(@Nullable
                   @Nullable java.lang.Object obj,
                   int i)
            throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.set(java.lang.Object, java.lang.Object)

getFloat

public float getFloat(@Nullable
                      @Nullable java.lang.Object obj)
               throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is inaccessible.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.get(java.lang.Object)

getDouble

public double getDouble(@Nullable
                        @Nullable java.lang.Object obj)
                 throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is inaccessible.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.get(java.lang.Object)

setLong

public void setLong(@Nullable
                    @Nullable java.lang.Object obj,
                    long l)
             throws java.lang.IllegalArgumentException

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:

WrappedReflectiveOperationException - if this Field object is enforcing Java language access control and the underlying field is either inaccessible or final.

java.lang.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.

java.lang.NullPointerException - if the specified object is null and the field is an instance field.

java.lang.ExceptionInInitializerError - if the initialization provoked by this method fails.

See Also:

Field.set(java.lang.Object, java.lang.Object)