edu.vub.at.objects.mirrors
Class OBJMirrorRoot

java.lang.Object
  edu.vub.at.objects.natives.NATNil
      edu.vub.at.objects.natives.NATByCopy
          edu.vub.at.objects.mirrors.OBJMirrorRoot

All Implemented Interfaces:

ATAbstractGrammar, ATConversions, ATExpression, ATNil, ATObject, ATStatement, java.io.Serializable

public class OBJMirrorRoot

extends NATByCopy

OBJMirrorRoot is a singleton which is shared by as a parent by all NATIntercessiveMirrors, It encodes the default behaviour to deal with invocation, selection and field assignment along the dynamic parent chain. This behaviour can be extracted, since these operations are always parameterised by a receiver object, namely the intercessive mirror in question.

Author:

smostinc

See Also:

Serialized Form

Field Summary

static OBJMirrorRoot	_INSTANCE_
static ATSymbol	_MIRROR_

Constructor Summary

private

OBJMirrorRoot()

Method Summary

protected ATObject	createChild(ATClosure code, boolean parentPointerType)
ATNil	meta_assignField(ATObject receiver, ATSymbol name, ATObject value) The effect of assigning a field on a mirror can be twofold.
ATObject	meta_clone() OBJMirrorRoot is a singleton object.
ATTable	meta_getStripes() By default, a native object (and also nil) has no stripes.
ATObject	meta_invoke(ATObject receiver, ATSymbol atSelector, ATTable arguments) The effect of invoking methods on a mirror (through meta_invoke) consists of checking whether the requested functionality is provided as a meta-operation by the principal that is wrapped by this mirror.
ATObject	meta_resolve() After deserialization, ensure that the mirror root remains unique.
ATObject	meta_select(ATObject receiver, ATSymbol atSelector) The effect of selecting fields or methods on a mirror (through meta_select) consists of checking whether the requested selector matches a field of the principal wrapped by this mirror.

Methods inherited from class edu.vub.at.objects.natives.NATByCopy

meta_pass

Methods inherited from class edu.vub.at.objects.natives.NATNil

asAmbientTalkObject, asJavaClassUnderSymbiosis, asJavaObjectUnderSymbiosis, asNativeBoolean, asNativeException, asNativeFarReference, asNativeFraction, asNativeNumber, asNativeNumeric, asNativeTable, asNativeText, base__opeql__opeql_, base_asActorMirror, base_asAsyncMessage, base_asBegin, base_asBoolean, base_asClosure, base_asDefinition, base_asExpression, base_asFarReference, base_asField, base_asHandler, base_asMessage, base_asMessageCreation, base_asMethod, base_asMirror, base_asNumber, base_asSplice, base_asStatement, base_asStripe, base_asSymbol, base_asTable, base_asUnquoteSplice, base_asVariableAssignment, base_init, base_isBoolean, base_isCallFrame, base_isClosure, base_isFarReference, base_isMessageCreation, base_isMethod, base_isMirror, base_isSplice, base_isStripe, base_isSymbol, base_isTable, base_isUnquoteSplice, base_isVariableAssignment, base_new, equals, isAmbientTalkObject, isJavaObjectUnderSymbiosis, isNativeBoolean, isNativeField, isNativeText, meta_addField, meta_addMethod, meta_assignVariable, meta_defineField, meta_doesNotUnderstand, meta_eval, meta_extend, meta_getDynamicParent, meta_getLexicalParent, meta_grabField, meta_grabMethod, meta_isCloneOf, meta_isRelatedTo, meta_isStripedWith, meta_listFields, meta_listMethods, meta_lookup, meta_newInstance, meta_print, meta_quote, meta_receive, meta_respondsTo, meta_send, meta_share, readResolve, toString, writeReplace

Methods inherited from class java.lang.Object

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

Field Detail

_MIRROR_

public static final ATSymbol _MIRROR_

_INSTANCE_

public static final OBJMirrorRoot _INSTANCE_

Constructor Detail

OBJMirrorRoot

private OBJMirrorRoot()

Method Detail

meta_invoke

public ATObject meta_invoke(ATObject receiver,
                            ATSymbol atSelector,
                            ATTable arguments)
                     throws InterpreterException

The effect of invoking methods on a mirror (through meta_invoke) consists of checking whether the requested functionality is provided as a meta-operation by the principal that is wrapped by this mirror. Since such meta-operations are intercepted and forwarded to allow for interception, the mirage is expected to have a method for the given selector albeit prefixed with 'magic_'.

Specified by:

meta_invoke in interface ATObject

Overrides:

meta_invoke in class NATNil

Throws:

InterpreterException

meta_clone

public ATObject meta_clone()
                    throws InterpreterException

OBJMirrorRoot is a singleton object.

Specified by:

meta_clone in interface ATObject

Overrides:

meta_clone in class NATNil

Throws:

InterpreterException

createChild

protected ATObject createChild(ATClosure code,
                               boolean parentPointerType)
                        throws InterpreterException

Overrides:

createChild in class NATNil

Throws:

InterpreterException

meta_select

public ATObject meta_select(ATObject receiver,
                            ATSymbol atSelector)
                     throws InterpreterException

The effect of selecting fields or methods on a mirror (through meta_select) consists of checking whether the requested selector matches a field of the principal wrapped by this mirror. If this is the case, the principal's ('meta_get' + selector) method will be invoked. Else the selector might identify one of the principal's meta-operations. If this is the case, then an AmbientTalk representation of the Java method ('meta_' + selector) will be returned.

Because an explicit AmbientTalk method invocation must be converted into an implicit Java method invocation, the invocation must be deified ('upped'). To uphold stratification of the mirror architecture, the result of this operation should be a mirror on the result of the Java method invocation.

Note that only when the principal does not have a matching meta_level field or method the mirror itself will be tested for a corresponding base_level behaviour (e.g. for its base field or for operators such as ==). In the latter case, stratification is not enforced. This is due to the fact that the said fields and methods are not meta-level behaviour, rather they are base-level operations which happen to be applicable on a mirror. An added advantage of this technique is that it permits a mirror to have a field referring to its principal.

Specified by:

meta_select in interface ATObject

Overrides:

meta_select in class NATNil

Throws:

InterpreterException

meta_assignField

public ATNil meta_assignField(ATObject receiver,
                              ATSymbol name,
                              ATObject value)
                       throws InterpreterException

The effect of assigning a field on a mirror can be twofold. Either a meta_field of the reflectee is altered (in this case, the passed value must be a mirror to uphold stratification). Otherwise it is possible that a base field of the mirror itself is changed.

Specified by:

meta_assignField in interface ATObject

Overrides:

meta_assignField in class NATNil

Throws:

InterpreterException

meta_resolve

public ATObject meta_resolve()
                      throws InterpreterException

After deserialization, ensure that the mirror root remains unique.

Specified by:

meta_resolve in interface ATObject

Overrides:

meta_resolve in class NATByCopy

Throws:

InterpreterException

meta_getStripes

public ATTable meta_getStripes()
                        throws InterpreterException

Description copied from class: NATNil

By default, a native object (and also nil) has no stripes.

Specified by:

meta_getStripes in interface ATObject

Overrides:

meta_getStripes in class NATNil

Throws:

InterpreterException