  Client Request() Target* Request ( ) Adapter SpecificRequest() (implementation) specificRequest() Adaptee Convert the interface of a class into another inteface clients expect.  Client Request() Target* Request( ) Adapter adaptee->SpecifricRequest() adaptee specificRequest() Adaptee  ConstraintStateVariable ConstraintVariableStateVariable (to QOCA class hierarchy) (to Unidraw class hierarchy)  ! GetChildren(node) CreateGraphicNode(Node) Display() BuildTree(Node n) TreeDisplay (Client,Target ) GetChildren(node) CreateGraphicNode(Node) DirectoryTreeDisplay (Adapter) FileSystemEntity (Adaptee) GetChildren(n) for each child { AddGraphicNode(CreateGraphi cNode(child)) BuildTree(child) }  " SetDelegate(Delegate) Display() BuildTree(Node n) TreeDisplay* (Client) GetChildren(TreeDisplay, Node) CreateGraphicNode(TreeDisplay, Node) TreeAccessorDelegate* (Target) GetChildren(TreeDisplay, Node) CreateGraphicNode(TreeDisplay, Node) CreateFile() DeleteFile() DirectoryBrowser (Adapter) FileSystemEntity (Adaptee) delegate->GetChildren(this, n) for each child{ AddGraphicNode( delegate->CreateGraphicNode(this, child) ) BuildTree(child) } delegate #$% Object* value: value ValueModel* getBlock setBlock value: value PluggableAdaptor ^ getBlock value:adaptee adaptee . Target* Request ( ) Adapter SpecificRequest() (implementation) specificRequest() Adaptee Convert the interface of a class into another inteface clients. expect.  Client Request() Target* Request( ) Adapter adaptee->SpecifricRequest() adaptee specificRequest() Adaptee  ConstraintStateVariable ConstraintVariableStateVariable (to