Class CObjectCon

class CObjectCon : public CBase;

Description

An object container.

An object container acts as a home for a set of related reference counting objects.

A reference counting object, a CObject type, must be added to an object container. Only one instance of a given reference counting object can be held by an object container, i.e. each object within an object container must be distinct.

Object containers are constructed by an object container index, a CObjectConIx type.

Note that this class is not intended for user derivation.

Derivation

• CBase - Base class for all classes to be instantiated on the heap

• CObjectCon - An object container

Members

Defined in CObjectCon:
AddL(), At(), AtL(), CObjectCon(), CheckUniqueFullName(), CheckUniqueFullName(), Count(), FindByFullName(), FindByName(), NewL(), Remove(), UniqueID(), iUniqueID, operator[](), ~CObjectCon()

Inherited from CBase:
Delete(), Extension_(), operator new()

See also:

• CObject
• CObjectConIx

static IMPORT_C CObjectCon *NewL();

Description

Creates an object container.

Open code rarely, if ever, explicitly calls this function. Instead, call the CreateL() member function of the container index, CObjectConIx, which uses this function in its implementation.

Return value

CObjectCon * A pointer to the new object container.

IMPORT_C ~CObjectCon();

Description

Destructor.

Frees all resources owned by the object container, prior to its destruction.

In particular, it destroys all contained reference counting objects.

See also:

• CObject

protected: IMPORT_C CObjectCon(TInt aUniqueID);

Description

Constructor taking a unique Id.

Parameters

TInt aUniqueID The unique Id value.

IMPORT_C void Remove(CObject *anObj);

Description

Removes a reference counting object from this object container.

The specified reference counting object is destroyed on removal.

Parameters

CObject *anObj A pointer to the reference counting object to be removed.

Panic codes

E32USER-CBase 35 if the reference counting object is not held by this object container.

IMPORT_C void AddL(CObject *anObj);

Description

Adds a reference counting object to this object container.

If the specified reference counting object has a name, it must be valid, otherwise the function leaves with KErrBadName; in addition, the reference counting object's full name must be unique to this object container, otherwise the function leaves with KErrAlreadyExists.

If the specified reference counting object has no name, then the object itself must be unique to the object container, i.e. the object container should not already contain the same reference counting object, otherwise the function leaves with KErrAlreadyExists.

Parameters

CObject *anObj A pointer to the reference counting object to be added.

IMPORT_C CObject *operator[](TInt anIndex);

Description

Gets a pointer to the reference counting object located at the specified offset within the object container.

Parameters

TInt anIndex The offset of the reference counting object within the object container. Offset is relative to zero.

Return value

CObject * A pointer to the owning reference counting object.

Panic codes

E32USER-CBase 21 if anIndex is negative or is greater than or equal to the total number of objects held by the container.

IMPORT_C CObject *At(TInt aFindHandle) const;

Description

Gets a pointer to the reference counting object with the specified find-handle number.

A find-handle number is an integer which uniquely identifies a reference counting object with respect to its object container.

Parameters

TInt aFindHandle The find-handle number of the reference counting object. The unique Id part of this number must be the same as the unique Id of this container. The index part of the find-handle number must be a valid index.

Return value

CObject * A pointer to the reference counting object.

Panic codes

E32User-CBase 38 if the unique Id part of aFindHandle is not the same as the unique Id of this container. E32User-CBase 39 if the index part of aFindHandle is negative or greater than or equal to the total number of reference counting objects held by this object container.

IMPORT_C CObject *AtL(TInt aFindHandle) const;

Description

Gets a pointer to the reference counting object with the specified find-handle number, and leaves on error..

A find-handle number is an integer which uniquely identifies a reference counting object with respect to its object container.

Parameters

TInt aFindHandle The find-handle number of the reference counting object. The unique Id part of this number must be the same as the unique Id of this container. The index part of the find-handle number must be a valid index.

Return value

CObject * A pointer to the reference counting object.

Leave codes

KErrBadHandle if the unique Id part of aFindHandle is not the same as the unique Id of this container. KErrArgument if the index part of aFindHandle is negative or greater than or equal to the total number of reference counting objects held by this object container.

IMPORT_C TInt CheckUniqueFullName(const CObject *anOwner, const TDesC &aName) const;

Description

Checks that a name will be unique.

The function checks that no reference counting object exists in this object container with the same full name as that generated from the specified name and the specified owning reference counting object.

This is a useful test to ensure that the name for a potential new reference counting object will result in a unique full name.

Parameters

const CObject *anOwner A pointer to a potential owning reference counting object. const TDesC &aName The name for a potential new reference counting object.

Return value

TInt KErrNone, if the full name does not already exist in this object container; KErrBadName, if the specified name is invalid; KErrAlreadyExists, if a reference counting object with the same fullname as the generated one already exists in this object container.

IMPORT_C TInt CheckUniqueFullName(const CObject *anObject) const;

Description

Checks that the specified reference counting object does not already exist in this object container.

Uniqueness is decided by name, if the object has a name, otherwise by pointer.

If the reference counting object has a name, then it is unique only if there is no other reference counting object in the container with the same full name.

If the reference counting object has no name, then it is unique only if there is no other reference counting object in the container with the same pointer.

Parameters

const CObject *anObject A pointer to the reference counting object to be checked.

Return value

TInt KErrNone, if the reference counting object does not already exist in this object container; KErrBadName, if the name of the reference counting object is invalid; KErrAlreadyExists, if the reference counting object already exists.

IMPORT_C TInt FindByName(TInt &aFindHandle, const TDesC &aMatch, TName &aName) const;

Description

Searches for the reference counting object whose name matches the specified match pattern.

The search starts at the reference counting object following the one associated with the specified find-handle number. If the specified find-handle number is zero, then searching starts at the beginning of the object container.

Notes:

1. names are folded for the purpose of pattern matching

2. if the specified find-handle number is non-zero, then the unique Id part of the number must be the same as the unique Id of this container.

Parameters

TInt &aFindHandle On entry, contains the find-handle number of a reference counting object from where searching is to start, or zero. On return, if an object is found, then this is set to the find-handle number of that object; if no object is found, then this is set to a generated number, the index part of which has the value 0x7fff. If the object container is empty, then this reference is not changed. const TDesC &aMatch The match pattern. TName &aName A modifiable buffer descriptor with a defined maximum length. On return, if an object is found, then this contains the name of that object; if no object is found, then the length of this descriptor is set to zero. If the object container is empty, then this reference is not changed.

Return value

TInt KErrNone, if a matching reference counting object is found; KErrNotFound, if no matching reference counting object can be found or the object container is empty.

Panic codes

E32User-CBase 38 if aFindHandle is non-zero and the unique Id part of it is not the same as the unique Id of this container.

IMPORT_C TInt FindByFullName(TInt &aFindHandle, const TDesC &aMatch, TFullName &aFullName) const;

Description

Searches for the reference counting object whose full name matches the specified match pattern.

The search starts at the reference counting object following the one associated with the specified find-handle number. If the specified find-handle number is zero, then searching starts at the beginning of the object container.

Notes:

1. names are folded for the purpose of pattern matching

2. if the specified find-handle number is non-zero, then the unique Id part of the number must be the same as the unique Id of this container.

Parameters

TInt &aFindHandle On entry, contains the find-handle number of a reference counting object from where searching is to start or zero. On return, if an object is found, then this is set to the find-handle number of that object; if no object is found, then this is set to a generated number, the index part of which has the value 0x7fff. If the object container is empty, then this reference is not changed. const TDesC &aMatch The match pattern. TFullName &aFullName A modifiable buffer descriptor with a defined maximum length. On return, if an object is found, then this contains the full name of that object; if no object is found, then the length of this descriptor is set to zero. If the object container is empty, then this reference is not changed.

Return value

TInt KErrNone, if a matching reference counting object is found; KErrNotFound, if no matching reference counting object can be found or the object container is empty.

Panic codes

E32User-CBase 38 if aFindHandle is non-zero and the unique Id part of it is not the same as the unique Id of this container.

inline TInt UniqueID() const;

Description

Gets this object container's unique ID.

Return value

TInt The unique ID value.

inline TInt Count() const;

Description

Gets the number of reference counting objects in this object container.

Return value

TInt The number of objects.

TInt iUniqueID;

Description

The object container's unique Id value.