Module openj9.dtfj

Package com.ibm.dtfj.java.javacore

Class JCJavaClass

java.lang.Object

com.ibm.dtfj.java.javacore.JCJavaClass

All Implemented Interfaces:

JavaClass

public class JCJavaClass
extends Object
implements JavaClass

Field Summary

Fields declared in interface com.ibm.dtfj.java.JavaClass

MODIFIERS_UNAVAILABLE

Constructor Summary

Constructors

Constructor	Description
JCJavaClass(JCJavaRuntime javaRuntime, String className)

Method Summary

Modifier and Type	Method	Description
void	addMethod(JavaMethod method)	NON-DTFJ For internal building purposes only.
JavaClassLoader	getClassLoader()	Fetch the class loader associated with this class.
JavaClass	getComponentType()	component type only for arrays
Iterator	getConstantPoolReferences()	Java classes may refer to other classes and to String objects via the class's constant pool.
Iterator	getDeclaredFields()	Get the set of fields declared in this class.
Iterator	getDeclaredMethods()	Get the set of methods declared in this class.
ImagePointer	getID()	The ID of a class is a pointer to a section of memory which identifies the class.
long	getInstanceSize()	Returns the size in bytes of an instance of this class on the heap.
Iterator	getInterfaces()	Get the set of names of interfaces directly implemented by this class.
int	getModifiers()	Return the Java language modifiers for this class.
String	getName()	Get the name of the class.
JavaObject	getObject()	Instance object of this class
JavaObject	getProtectionDomain()	Returns the protection domain for this class.
Iterator	getReferences()	Get the set of references from this class.
JavaClass	getSuperclass()	Returning null is permissable for cases like Object, primitives, interfaces, etc..
String	internalGetName()	NON-DTFJ For internal building purposes only.
boolean	isArray()	Same as the J9 System Core implementation for DTFJ.
void	setClassLoader(JavaClassLoader classLoader)	NON-DTFJ For internal building purposes only.
void	setID(long classID)	NON-DTFJ For internal building purposes only.
void	setJavaObject(JavaObject javaObject)	NON-DTFJ For internal building purposes only.
void	setJavaSuperClass(long superClassID)	NON-DTFJ For internal building purposes only.
void	setModifiers(int modifiers)	NON-DTFJ For internal building purposes only.

Methods declared in class java.lang.Object

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

Methods declared in interface com.ibm.dtfj.java.JavaClass

equals, hashCode

Constructor Details

JCJavaClass

public JCJavaClass(JCJavaRuntime javaRuntime,
 String className)
            throws JCInvalidArgumentsException

Parameters:

javaRuntime -

className -

Throws:

JCInvalidArgumentsException

Method Details

getClassLoader

public JavaClassLoader getClassLoader()
                               throws CorruptDataException

Description copied from interface: JavaClass

Fetch the class loader associated with this class. Classes defined in the bootstrap class loader (including classes representing primitive types or void) will always return a JavaClassLoader representing the bootstrap class loader. This asymmetry with java.lang.Class#getClassLoader() is intentional.

Specified by:

getClassLoader in interface JavaClass

Returns:

the JavaClassLoader in which this class was defined

Throws:

CorruptDataException - if the class loader for this class cannot be found (a class cannot exist without a loader so this implies corruption)

getComponentType

public JavaClass getComponentType()
                           throws CorruptDataException

component type only for arrays

Specified by:

getComponentType in interface JavaClass

Returns:

a JavaClass representing the component type of this array class

Throws:

CorruptDataException

getConstantPoolReferences

public Iterator getConstantPoolReferences()

Description copied from interface: JavaClass

Java classes may refer to other classes and to String objects via the class's constant pool. These references are followed by the garbage collector, forming edges on the graph of reachable objects. This getConstantPoolReferences() may be used to determine which objects are referred to by the receiver's constant pool.

Although Java VMs typically permit only Class and String objects in the constant pool, some esoteric or future virtual machines may permit other types of objects to occur in the constant pool. This API imposes no restrictions on the types of JavaObjects which might be included in the Iterator.

No assumption should be made about the order in which constant pool references are returned.

Classes may also refer to objects through static variables. These may be found with the getDeclaredFields() API. Objects referenced by static variables are not returned by getConstantPoolReferences() unless the object is also referenced by the constant pool.

Specified by:

getConstantPoolReferences in interface JavaClass

Returns:

an iterator over the collection of JavaObjects which are referred to by the constant pool of this class

See Also:

• JavaObject
• CorruptData

getDeclaredFields

public Iterator getDeclaredFields()

Description copied from interface: JavaClass

Get the set of fields declared in this class.

Specified by:

getDeclaredFields in interface JavaClass

Returns:

an iterator over the collection of fields declared in this class.

See Also:

• JavaField
• CorruptData

getDeclaredMethods

public Iterator getDeclaredMethods()

Description copied from interface: JavaClass

Get the set of methods declared in this class.

Specified by:

getDeclaredMethods in interface JavaClass

Returns:

an iterator over the collection of methods declared in this class.

See Also:

• JavaMethod
• CorruptData

getID

public ImagePointer getID()

Description copied from interface: JavaClass

The ID of a class is a pointer to a section of memory which identifies the class. The contents of this memory are implementation defined.

In some implementations getID() and getObject().getID() may return the same value. This implies that the class object is also the primary internal representation of the class. DTFJ users should not rely on this behaviour.

In some implementations, getID() may return null for some classes. This indicates that the class is a synthetic class which has been constructed for DTFJ purposes only. The class has no physical representation in the VM.

Specified by:

getID in interface JavaClass

Returns:

a pointer to the class

getInterfaces

public Iterator getInterfaces()

Description copied from interface: JavaClass

Get the set of names of interfaces directly implemented by this class.

Specified by:

getInterfaces in interface JavaClass

Returns:

an iterator over the collection of the names of interfaces directly implemented by this class. Some JVM implementations may choose to load interfaces lazily, so only the names are returned. The JavaClass objects may be found through the defining class loader.

See Also:

• String
• JavaClassLoader.findClass(String)
• CorruptData

getModifiers

public int getModifiers()
                 throws CorruptDataException

Description copied from interface: JavaClass

Return the Java language modifiers for this class.

The modifiers are defined by the JVM Specification.

Return MODIFIERS_UNAVAILABLE if the modifiers are unavailable. This might be the case if DTFJ is operating against an artefact such as a portable heap dump that does not contain information about a class's modifiers.

Note that, for inner classes, the actual modifiers are returned, not the synthetic modifiers. For instance, a class will never have its 'protected' modifier set, even if the inner class was a protected member, since 'protected' is not a legal modifier for a class file.

Specified by:

getModifiers in interface JavaClass

Returns:

the modifiers for this class

Throws:

CorruptDataException - if modifiers not set

See Also:

• JavaClass.getModifiers()

getName

public String getName()
               throws CorruptDataException

Description copied from interface: JavaClass

Get the name of the class.

Specified by:

getName in interface JavaClass

Returns:

the name of the class in the form: "full/package/class$innerclass"

Throws:

CorruptDataException - if class name is not set

See Also:

• JavaClass.getName()

getObject

public JavaObject getObject()
                     throws CorruptDataException

Instance object of this class

Specified by:

getObject in interface JavaClass

Returns:

the java.lang.Class object associated with this class

Throws:

CorruptDataException - if no instance of this class is set

See Also:

• JavaClass.getObject()

getSuperclass

public JavaClass getSuperclass()
                        throws CorruptDataException

Returning null is permissable for cases like Object, primitives, interfaces, etc..

Specified by:

getSuperclass in interface JavaClass

Returns:

JavaClass of this class's superclass.

Throws:

CorruptDataException - if super class not found.

See Also:

• JavaClass.getSuperclass()

getInstanceSize

public long getInstanceSize()
                     throws DataUnavailable,
CorruptDataException

Description copied from interface: JavaClass

Returns the size in bytes of an instance of this class on the heap.

The call is only meaningful for a non-array JavaClass, where all instances of the class are of the same size. If this method is called on a JavaArrayClass, where instances can be of different sizes, an UnsupportedOperationException will be thrown. DataUnavailable can be thrown if no value is available: for example when DTFJ is examining a javacore, where the instance size for a class is not recorded.

Specified by:

getInstanceSize in interface JavaClass

Returns:

size in bytes of an instance

Throws:

DataUnavailable

CorruptDataException

isArray

public boolean isArray()
                throws CorruptDataException

Same as the J9 System Core implementation for DTFJ.

Specified by:

isArray in interface JavaClass

Returns:

true if an array

Throws:

CorruptDataException

See Also:

• JavaClass

setID

public void setID(long classID)
           throws JCInvalidArgumentsException

NON-DTFJ
For internal building purposes only. Do not call outside the DTFJ implementation.

Parameters:

classID - which is a valid hexadecimal address

Throws:

JCInvalidArgumentsException - if invalid address is passed as an ID

internalGetName

public String internalGetName()

NON-DTFJ
For internal building purposes only. Do not call outside the DTFJ implementation.

Returns:

class Name

setClassLoader

public void setClassLoader(JavaClassLoader classLoader)

NON-DTFJ
For internal building purposes only. Do not call outside the DTFJ implementation.

Parameters:

classLoader -

setJavaSuperClass

public void setJavaSuperClass(long superClassID)

NON-DTFJ
For internal building purposes only. Do not call outside the DTFJ implementation.

Parameters:

superClassID -

setJavaObject

public void setJavaObject(JavaObject javaObject)

NON-DTFJ
For internal building purposes only. Do not call outside the DTFJ implementation.

Parameters:

javaObject -

setModifiers

public void setModifiers(int modifiers)

NON-DTFJ
For internal building purposes only. Do not call outside the DTFJ implementation.

Parameters:

java - class modifiers

getReferences

public Iterator getReferences()

Description copied from interface: JavaClass

Get the set of references from this class.

Specified by:

getReferences in interface JavaClass

Returns:

an iterator of JavaReferences

See Also:

• JavaReference
• CorruptData

addMethod

public void addMethod(JavaMethod method)

NON-DTFJ
For internal building purposes only. Do not call outside the DTFJ implementation.

Parameters:

java - method - a method declared by this class

getProtectionDomain

public JavaObject getProtectionDomain()
                               throws DataUnavailable,
CorruptDataException

Description copied from interface: JavaClass

Returns the protection domain for this class.

Specified by:

getProtectionDomain in interface JavaClass

Returns:

the protection domain or null for the default protection domain

Throws:

DataUnavailable

CorruptDataException