It is time to put everything together in the configuration file, command-chain.xml

All alias (outgoing transitions) used by JSP's is associated to a command-chains in the Action URLs mapping section. This mapping makes a loose coupling between the JSP's and the command-chains, and thus several alias can be used for the same command-chain.

In the example the alias login is associated with the command-chain handleLogin.

            <actions>
                <action name="login"            chain="handleLogin" />
                <action name="logout"           chain="handleLogout" />

                <action name="main"             chain="main" />

                <!-- CREATE -->
                <action name="add"              chain="handleAddComponent"/>
                <action name="create"           chain="handleCreateComponent"/>
                <action name="createManifest"   chain="handleCreateManifest"/>
                <action name="createAnnotation" chain="handleCreateAnnotation"/>
                
                

In the command definition section is the implementation of a command associated with a name and initialization parameters. This is convenient when the command is used with the same parameters in several command-chains. Defining all commands is not nessesary, but I find the command-chain definition section to become more readable using shorter names for the commands, but again it is a matter of taste. This is optional as a command implementation can be defined inline in a command-chain definition.

                <command-def name="ReadModel"
                             class="se.kmr.scam.client.http.command.ReadModel">
                   <init-param name="depth" value="0"/>
                   <init-param name="maxDepth" value="1"/>
                   <init-param name="includeAnnotations" value="false"/>
                </command-def>
                
                

The header of command-chain definitions section defines a default command-chain, an error handler command-chain and the default command chain executor class. The default command-chain is executed when no alias is provided in the request. The error handler is executed in case of an, unhandled, exception occures in the command chain executor.

                <chain-defs default="main"
                            errorhandler="error"
                            defaultclass="se.kmr.scam.client.http.CommandChainImpl">


                    <!-- LOCAL: Base chain -->
                    <chain name="_baseChain" class="se.kmr.scam.client.http.CommandChainImpl">
                         <command-ref ref="SyncManifest"/>
                    </chain>
                    
                

This example includes the definition of the _baseChain command-chain. Since no alias is associated with this name can this command-chain not be requested directly. The class attribute value overides the value of the default class defined in the header.

                    <chain name="handleCreateManifest" extends="_baseChain">
                        <command-ref ref="CreateManifest"/>
                        <command-ref ref="CreateDefaultModel"/>
                        <command-ref ref="StoreModel"/>
                        <include chain="_editView"/>
                    </chain>
                    
                

An alternative to define the same sequence of command in several command-chains is to include other command-chains. The include directive will append commands from the referenced command-chain into current command-chain definition. The command-chain definition attribute extends conveniently prepends the referenced command-chain into the current command-chain .