Java Debug Interface

com.sun.jdi
Interface Value

All Superinterfaces:
Mirror
All Known Subinterfaces:
ArrayReference, BooleanValue, ByteValue, CharValue, ClassLoaderReference, ClassObjectReference, DoubleValue, FloatValue, IntegerValue, LongValue, ObjectReference, PrimitiveValue, ShortValue, StringReference, ThreadGroupReference, ThreadReference, VoidValue

public interface Value
extends Mirror

The mirror for a value in the target VM. This interface is the root of a value hierarchy encompassing primitive values and object values.

Some examples of where values may be accessed:

ObjectReference.getValue(Field) - value of a field
StackFrame.getValue(LocalVariable) - value of a variable
VirtualMachine.mirrorOf(double) - created in the target VM by the JDI client
ModificationWatchpointEvent.valueToBe() - returned with an event

The following table illustrates which subinterfaces of Value are used to mirror values in the target VM --

Subinterfaces of PrimitiveValue
Kind of value For example -
expression in target
Is mirrored as an
instance of
Type of value
Value.type()
a boolean true BooleanValue BooleanType
a byte (byte)4 ByteValue ByteType
a char 'a' CharValue CharType
a double 3.1415926 DoubleValue DoubleType
a float 2.5f FloatValue FloatType
an int 22 IntegerValue IntegerType
a long 1024L LongValue LongType
a short (short)12 ShortValue ShortType
a void   VoidValue VoidType
Subinterfaces of ObjectReference
Kind of value For example -
expression in target
Is mirrored as an
instance of
Type of value
Value.type()
a class instance this ObjectReference ClassType
an array new int[5] ArrayReference ArrayType
a string "hello" StringReference ClassType
a thread Thread.currentThread() ThreadReference ClassType
a thread group Thread.currentThread()
  .getThreadGroup()
ThreadGroupReference ClassType
a java.lang.Class
instance
this.getClass() ClassObjectReference ClassType
a class loader this.getClass()
  .getClassLoader()
ClassLoaderReference ClassType
Other
Kind of value For example -
expression in target
Is mirrored as Type of value
null null null n/a

Since:
1.3

Method Summary
 Type type()
          Returns the run-time type of this value.
 
Methods inherited from interface com.sun.jdi.Mirror
toString, virtualMachine
 

Method Detail

type

Type type()
Returns the run-time type of this value.

Returns:
a Type which mirrors the value's type in the target VM.
See Also:
Type

Java Debug Interface

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