Apple WebObjects 3.5 Manual de usuario descargar pdf (Pagina 137)

Controlling Component State

137

responsibility for maintaining any needed component state. For this reason,

it’s rarely advisable to turn off page caching.

Using awake and sleep

Another way to control the amount of component state that’s maintained

between cycles is to make use of WOComponent’s

awake and sleep methods.

Unlike WOComponent’s

init method that’s invoked just once in the life of

the component, a component’s

awake and sleep methods are invoked at the

beginning and end of any request-response loop that involves the

component.

By moving a component’s variable initialization routines from its

init method

to its

awake method and implementing a sleep method to release those

variables, you can reduce the space requirements for storing a component.

For example, the code for DodgeLite’s Main component could be changed

to:

// rewritten DodgeLite Main.wos

id models, model, selectedModels;

id prices, price, selectedPrices;

id types, type, selectedTypes;

- awake {

anApplication = [WOApplication application];

models = [[anApplication modelsDict] allValues];

types = [[anApplication typesDict] allValues];

prices = [anApplication prices];

}

- sleep {

models = nil;

types = nil;

prices = nil;

}

Note that in WebScript you set a variable to nil to mark it for release. In

Objective-C you send the object a

release message:

- sleep {

[models release];

[types release];

[prices release];

}

Of course, what you save in storage by moving variable initialization to the

awake method is lost in performance, since these variables will be

reinitialized on each cycle of the request-response loop.

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