Adding Parameters to an asadmin Subcommand

The parameters of an asadmin subcommand are the options and operands of the subcommand.

• Options control how the asadmin utility performs a subcommand.

• Operands are the objects on which a subcommand acts. For example, the operand of the start-domain(1) subcommand is the domain that is to be started.

The following topics are addressed here:

• Representing a Parameter of an asadmin Subcommand

• Identifying a Parameter of an asadmin Subcommand

• Specifying Whether a Parameter Is an Option or an Operand

• Specifying the Name of an Option

• Specifying the Acceptable Values of a Parameter

• Specifying the Default Value of a Parameter

• Specifying Whether a Parameter Is Required or Optional

• Example of Adding Parameters to an asadmin Subcommand

Representing a Parameter of an asadmin Subcommand

Represent each parameter of a subcommand in your implementation as a field or as the property of a JavaBeans^TM specification setter method. Use the property of a setter method for the following reasons:

• To provide data encapsulation for the parameter

• To add code for validating the parameter before the property is set

Identifying a Parameter of an asadmin Subcommand

Identifying a parameter of an asadmin subcommand enables GlassFish Server to perform the following operations at runtime on the parameter:

• Validation. The GlassFish Server determines whether all required parameters are specified and returns an error if any required parameter is omitted.

• Injection. Before the subcommand runs, the GlassFish Server injects each parameter into the required field or method before the subcommand is run.

• Usage message generation. The GlassFish Server uses reflection to obtain the list of parameters for a subcommand and to generate the usage message from this list.

• Localized string display. If the subcommand supports internationalization and if localized strings are available, the GlassFish Server can automatically obtain the localized strings for a subcommand and display them to the user.

To identify a parameter of a subcommand, annotate the declaration of the item that is associated with the parameter with the org.glassfish.api.Param annotation. This item is either the field or setter method that is associated with the parameter.

To specify the properties of the parameter, use the elements of the @Param annotation as explained in the sections that follow.

Specifying Whether a Parameter Is an Option or an Operand

Whether a parameter is an option or an operand determines how a user must specify the parameter when running the subcommand:

• If the parameter is an option, the user must specify the option with the parameter name.

• If the parameter is an operand, the user may omit the parameter name.

To specify whether a parameter is an option or an operand, set the primary element of the @Param annotation as follows:

• If the parameter is an option, set the primary element to false. This value is the default.

• If the parameter is an operand, set the primary element to true.

Specifying the Name of an Option

The name of an option is the name that a user must type on the command line to specify the option when running the subcommand.

The name of each option that you add in your implementation of an asadmin subcommand can have a long form and a short form. When running the subcommand, the user specifies the long form and the short form as follows:

• The short form of an option name has a single dash (-) followed by a single character.

• The long form of an option name has two dashes (--) followed by an option word.

For example, the short form and the long form of the name of the option for specifying terse output are as follows:

• Short form: -m

• Long form: --monitor

Option names are case-sensitive.

Specifying the Long Form of an Option Name

To specify the long form of an option name, set the name element of the @Param annotation to a string that specifies the name. If you do not set this element, the default name depends on how you represent the option.

• If you represent the option as a field, the default name is the field name.

• If you represent the option as the property of a JavaBeans specification setter method, the default name is the property name from the setter method name. For example, if the setter method setPassword is associated with an option, the property name and the option name are both password.

Specifying the Short Form of an Option Name

To specify the short form of an option name, set the shortName element of the @Param annotation to a single character that specifies the short form of the parameter. The user can specify this character instead of the full parameter name, for example -m instead of --monitor. If you do not set this element, the option has no short form.

Specifying the Acceptable Values of a Parameter

When a user runs the subcommand, the GlassFish Server validates option arguments and operands against the acceptable values that you specify in your implementation.

To specify the acceptable values of a parameter, set the acceptableValues element of the @Param annotation to a string that contains a comma-separated list of acceptable values. If you do not set this element, any string of characters is acceptable.

Specifying the Default Value of a Parameter

The default value of a parameter is the value that is applied if a user omits the parameter when running the subcommand.

To specify the default value of a parameter, set the defaultValue element of the @Param annotation to a string that contains the default value. If you do not set this element, the parameter has no default value.

Specifying Whether a Parameter Is Required or Optional

Whether a parameter is required or optional determines how a subcommand responds if a user omits the parameter when running the subcommand:

• If the parameter is required, the subcommand returns an error.

• If the parameter is optional, the subcommand runs successfully.

To specify whether a parameter is optional or required, set the optional element of the @Param annotation as follows:

• If the parameter is required, set the optional element to false. This value is the default.

• If the parameter is optional, set the optional element to true.

Example of Adding Parameters to an asadmin Subcommand

Example 4–2 Adding Parameters to an asadmin Subcommand

This example shows the code for adding parameters to an asadmin subcommand with the properties as shown in the table.

...
import org.glassfish.api.Param;
...
{
…
    @Param
    String originator;
    
    @Param(name="description", optional=true)
    …
    String mycontainerDescription
    
    @Param (acceptableValues="true,false", defaultValue="false", optional=true)
    String enabled
    
    @Param(primary=true)
    String containername;
…
}