Use a command

 

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Overview

To use a command, the client creates an instance of the command and calls the execute method for the command. Depending on the command, calling other methods can be necessary. The specifics will vary with the application.

In the example application, the server is the CheckingAccountBean, an entity enterprise bean. In order to use this enterprise bean, the client gets a reference to the bean’s home interface. The client then uses the reference to the home interface and one of the finder methods for the bean to obtain a reference to the remote interface for the bean. If there is no appropriate bean, the client can create one using a create method on the home interface. The following code example illustrates the use of the ModifyCheckingAccountCmd command. This work takes place after an appropriate CheckingAccount bean has been found or created. The code instantiates a command, setting the input values by using one of the constructors defined for the command. The null argument indicates that the command should look up the server using the default target policy, and 1000 is the amount the command attempts to add to the balance of the checking account. After the command is instantiated, the code calls the setCheckingAccount method to identify the account to be modified. Finally, the execute method on the command is called.

{
...
CheckingAccount checkingAccount
... try 
{
    ModifyCheckingAccountCmd cmd =
    new ModifyCheckingAccountCmdImpl(null, 1000);
    cmd.setCheckingAccount(checkingAccount);
    cmd.execute();
} catch (Exception e) 
{
    System.out.println(e.getMessage());
}
...
}


 

Related tasks

Writing a command target (server)