Property Accessors

Accessing fields of the heap object

Properties of heap objects are accessed using a simple dot notation:

[ <alias>. ] <field> . <field>. <field>

An alias can be defined in the FROM Clause to identify the current object, i.e. row in the SQL analogy, on which the OQL statement operates. Without alias, the field is assumed to be one of the fields of the current object. Fields are attributes of the Java objects in the heap dump. Use the Object Inspector to find out about the available fields of an object.

Accessing Java Bean properties

[ <alias>. ] @<attribute> ...

Using the @ symbol, OQL accesses attributes of the underlying Java objects. The attributes are resolved via Bean Introspection. The following table lists some commonly used Java attributes.

Any heap object IObject objectId id of snapshot object
    objectAddress address of snapshot object
    class class of this object
    usedHeapSize shallow heap size
    retainedHeapSize retained heap size
    displayName display name
Class object IClass classLoaderId id of the class loader
Any array IArray length length of the array

Calling Java methods

[ <alias> . ] @<method>( [ <expression>, <expression> ] ) ...

Adding ( ) forces OQL to interpret this as a Java method call. The call is executed via reflection. Common Java methods.

$snapshot ISnapshot
getClasses()
a collection of all classes
   
getClassesByName(String name, boolean includeSubClasses)
a collection of classes
Class object IClass
hasSuperClass()
result is true if the class has a super class
   
isArrayType()
the result is true if the class is an array type

Build-in OQL functions

<function>( <parameter> )

Build-in functions.

toHex( number )
Print the number as hexadecimal
toString( object )
Returns the value of an object, e.g. the content of a String etc.
dominators( object )
The objects immediately dominated by the object
outbounds( object )
outbound referrer
inbounds( object )
inbound referrer
classof( object )
the class of the current object
dominatorof( object )
the immediate dominator, -1 if none