Author: irooskov(a)redhat.com Date: 2011-06-05 23:18:51 -0400 (Sun, 05 Jun 2011) New Revision: 31841 Added: trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_06.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_07.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_08.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_09.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_10.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_11.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_12.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_13.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_14.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_15.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_16.png trunk/bpel/docs/reference/en-US/images/reference/BPEL_Designer_17.png 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UTC (rev 31841) @@ -579,7 +579,7 @@ The <guilabel>Details</guilabel> tab allows you to select one of four basic actions: <property>Invoke</property>, <property>Receive</property>, <property>Reply</property> and <property>Assign</property>. Hovering the mouse over one of the selection buttons displays a brief description of that activity. </para> </section> - <section> + <section id="Reference-Details_tab-Invoke"> <title>Invoke</title> <figure> <title>Invoke</title> @@ -596,7 +596,7 @@ The checkbox labeled <guilabel>Use WSDL Message Parts Mapping</guilabel> provides an alternative to using variables for the request message. </para> </section> - <section> + <section id="Reference-Details_tab-Receive"> <title>Receive</title> <figure> <title>Receive</title> @@ -613,7 +613,7 @@ The <guilabel>Create a new Process Instance</guilabel> checkbox, when enabled, will cause the BPEL engine to start a new process. This will start a new conversation with a client. </para> </section> - <section> + <section id="Reference-Details_tab-Reply"> <title>Reply</title> <figure> <title>Reply</title> @@ -641,7 +641,7 @@ </mediaobject> </figure> </section> - <section> + <section id="Reference-Details_tab-Assign"> <title>Assign</title> <para> The <property>Assign</property> section is probably one of the more complex pages in the BPEL Designer, due to the nature of the BPEL <property>Assign</property> activity. The figure below shows the detail tab of an empty <property>Assign</property> activity with callouts describing each component: @@ -804,7 +804,7 @@ </tgroup> </table> </section> - <section> + <section id="Reference-Details_tab-Validate"> <title>Validate</title> <figure> <title>Validate</title> @@ -860,7 +860,7 @@ The <property>Pick</property> details tab allows you to specify whether the event will create a new process instance. <!-- See also the discussion of the Pick Activity. --> </para> </section> - <section> + <section id="Reference-Details_tab-OnMessage"> <title>OnMessage</title> <figure> <title>OnMessage</title> @@ -877,7 +877,7 @@ The <guilabel>Details</guilabel> tab allows you to specify the <property>Partner Link</property>, <property>Operation</property> and <property>Message Type</property> expected by the activity, and the process variable that will contain the received message data. </para> </section> - <section> + <section id="Reference-Details_tab-OnAlarm"> <title>OnAlarm</title> <figure> <title>OnAlarm</title> @@ -941,7 +941,7 @@ The optional <guilabel>Completion</guilabel> tab allows you to specify the early termination condition for the loop. </para> </section> - <section> + <section id="Reference-Details_tab-Wait"> <title>Wait</title> <figure> <title>Wait</title> @@ -1089,11 +1089,532 @@ <imageobject> <imagedata fileref="images/reference/BPEL_Designer_05.png"/> </imageobject> - </inlinemediaobject> activities. These do not correspond to actual BPEL elements however, and are simply placeholders for visualizing the beginning and end of the process flow: + </inlinemediaobject> activities. These do not correspond to actual BPEL elements however, and are simply placeholders for visualizing the beginning and end of the process flow. </para> </section> + <section> + <title>Assign</title> + <figure> + <title>Assign activity</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_06.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>Assign</property> activity allows you to manipulate variables and message contents that are defined in the process. See <xref linkend="Reference-Details_tab-Assign" /> for more information. + </para> + </section> + <section> + <title>Invoke</title> + <figure> + <title>Invoke activity</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_07.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>Invoke</property> activity is used to send a message to an external service (one-way invocation), and optionally wait for a response (request and response). An <property>Invoke</property> can also define a compensation handler and a fault handler to handle exception conditions. See <xref linkend="Reference-Details_tab-Invoke" /> for more information. + </para> + </section> + <section> + <title>Receive</title> + <figure> + <title>Receive activity</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_08.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>Receive</property> activity will wait for a specific message type from a service client. See <xref linkend="Reference-Details_tab-Receive" /> for more information. + </para> + </section> + <section> + <title>Reply</title> + <figure> + <title>Reply activity</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_09.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>Reply</property> activity is used to respond to clients with a specific message type, or fault message (if defined for the process interface). See <xref linkend="Reference-Details_tab-Reply" /> for more information. + </para> + </section> + <section> + <title>Validate</title> + <figure> + <title>Validate Input activity</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_10.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>Validate</property> activity is used to validate the values of variables against their XML Schema and WSDL data definitions. This includes the variable’s data type as well as structure. If validation fails, the BPEL standard fault invalidVariables is thrown. + </para> + <para> + Validation is typically performed just before sending messages to a partner or client, or after receiving a message to ensure the message contains all required data and that the data is as expected. See <xref linkend="Reference-Details_tab-Validate" /> for more information. + </para> + </section> + <section> + <title>Wait</title> + <figure> + <title>Wait activity</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_11.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + A <property>Wait</property> activity will delay process execution for a certain amount of time, or until a given date and time; this is typically used to invoke an operation at a certain time. For example to update process state hourly or daily, or to collect some information from another service at a certain time of day. See <xref linkend="Reference-Details_tab-Wait" /> for more information. + </para> + </section> </section> - </section> + <section> + <title>Structured activities</title> + <para> + Structured activities can be thought of as containers that can hold one or more activities. The <guilabel>Controls</guilabel> section of the <guilabel>Palette</guilabel> contains all of the <emphasis>structured activities</emphasis>. When you drag and drop one of these onto the drawing canvas, the BPEL Designer will create a basic skeleton of the activity, and assign default properties. + </para> + <para> + All structured activities will require some additional configuration before they are considered valid. For example, BPEL does not allow an empty <property>Sequence</property> activity. Invalid structured activities will be decorated with an error icon similar to basic activities. + </para> + <para> + Structured activities can be expanded and collapsed on the drawing canvas by clicking the plus and minus buttons at the bottom of the figure. Illustrated below is a collapsed and expanded <property>Sequence</property>: + </para> + <figure> + <title>Collapsed Sequence</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_12.png"/> + </imageobject> + </mediaobject> + </figure> + <figure> + <title>Expanded Sequence</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_13.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The following sections describe the structured activities and how each must be configured to be considered vaid for BPEL. + </para> + <section> + <title>If</title> + <figure> + <title>If, ElseIf and Else</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_14.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>If</property> activity allows conditional execution of one or more sequences of activities. It consists of a sequence of one or more conditional branches defined by <property>If</property> and optional <property>ElseIf</property> elements. The elements are evaluated in left-to-right order (or top-to-bottom if you have selected horizontal layout). An optional <property>Else</property> branch will be executed if none of the other conditions are true. + </para> + <para> + An <property>If</property> activity must define a condition (expressed as an XPath) and an activity which is executed if the condition evaluates true. To insert additional <property>ElseIf</property> and <property>Else</property> elements, right-click the <property>If</property> figure and select the desired element from the context menu. The figure above shows a complete <property>If</property> activity with optional <property>ElseIf</property> and <property>Else</property> elements. + </para> + </section> + <section> + <title>Pick</title> + <figure> + <title>Pick</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_15.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>Pick</property> activity will cause the process to wait for one of any number of messages to be received. An optional timer can be set to limit the time to wait for receipt of these messages. Activities to handle receipt of messages and timer expiration are defined in the <property>Pick</property>. Message receipts are handled by <property>OnMessage</property> activities (<xref linkend="Reference-Details_tab-OnMessage" />), and timer expiration is handled by the <property>OnAlaram</property> activity (<xref linkend="Reference-Details_tab-OnAlarm" />). + </para> + </section> + <section> + <title>While</title> + <figure> + <title>While</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_16.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>While</property> activity repeatedly executes the contained activity as long as a condition evaluates true at the beginning of each iteration. A <property>While</property> activity must define a condition and must contain an activity. + </para> + </section> + <section> + <title>ForEach</title> + <figure> + <title>ForEach</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_17.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + <property>ForEach</property> is a looping activity that executes the activities contained in its <property>Scope</property> a specified number of times. A counter variable, defined in the <property>ForEach</property> property detail tab, is used to keep track of the iterations. The <property>ForEach</property> properties must be configured with starting and ending value expressions for this counter variable. The counter is initially set to the starting value and activities in the <property>Scope</property> are executed until the counter exceeds the ending value. + </para> + <para> + This activity can also be configured to execute all iterations in parallel, meaning the enclosed <property>Scope</property> activity behaves as if multiple <property>Scopes</property> are enclosed in a <property>Flow</property> activity. + </para> + <para> + An optional early termination value can be defined, which will cause the loop to complete before the counter has reached its ending value. The <property>ForEach</property> will complete when the counter is equal to this early termination value for the sequential execution case. For the parallel execution case, the early termination value is the number of completed iterations. For example, the <property>ForEach</property> completes when at least <emphasis>some number</emphasis> of <emphasis>some action</emphasis> have finished. + </para> + </section> + <section> + <title>RepeatUntil</title> + <figure> + <title>RepeatUntil</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_18.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>RepeatUntil</property> activity repeatedly executes the contained activity as long as a condition evaluates true at the end of each iteration. A condition must be defined for a <property>RepeatUntil</property>, and it must contain an activity. + </para> + </section> + <section> + <title>Sequence</title> + <para> + A <property>Sequence</property> is a container for one or more other activities, which are executed in sequential order and (unlike <property>Scope</property> and <property>Flow</property> activities), has no other special characteristics. Because the conditional activities (<property>If</property>, <property>While</property>, <property>RepeatUntil</property> and <property>ForEach</property>) can have only one activity as the target of their execution, a <property>Sequence</property> is typically used to execute multiple activities. + </para> + <para> + For example, the <property>If</property> shown below contains only a single Assign activity: + </para> + <figure> + <title>Sequence</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_19.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + If it were necessary to perform an assignment and then invoke another web service, the <property>Assign</property> and <property>Invoke</property> could be contained within a <property>Sequence</property>. The <property>Sequence</property> would then become the target of the <property>If</property>: + </para> + <figure> + <title>Sequence</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_20.png"/> + </imageobject> + </mediaobject> + </figure> + <note> + <para> + The BPEL Designer will automatically create a <property>Sequence</property> if you drag-drop a second activity into any of the conditional activities. + </para> + </note> + </section> + <section> + <title>Scope</title> + <figure> + <title>Scope</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_21.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + A <property>Scope</property> provides a context for its enclosed activity. This context includes variables, partner links, message exchanges, correlation sets, event handlers, fault handlers, a compensation handler and a termination handler. These <property>Scope</property> contexts can be nested hierarchically where the root context is provided by the process itself. + </para> + <para> + A <property>Scope</property> can be thought of as a compartmentalized sub-process. If the <property>Scope</property> is declared as being <emphasis>isolated</emphasis>, then the variables and partner links shared with the process are locked to prevent other concurrent <property>Scopes</property> from altering them while a <property>Scope</property> is executing. <property>Scope</property> may also be nested to any depth and all variables, partner links and others defined in a <property>Scope</property>, are inherited by its children. Refer to <xref linkend="Reference-BPEL_Designer-Structured_Activities-Flow" /> for a discussion of concurrent execution. + </para> + <para> + To be valid, a <property>Scope</property> must have a single activity. The typical use of a Scope activity is to invoke a service and wait for a response message or timeout. In the above figure, the <property>Scope</property> has defined a message variable and a partner link used to interact with the invoked service. + </para> + </section> + <section id="Reference-BPEL_Designer-Structured_Activities-Flow"> + <title>Flow</title> + <para> + The <property>Flow</property> activity allows multiple activities to be executed in parallel. All activities or <property>Sequences</property> of activities that are contained in a <property>Flow</property>, are executed (or begun) at the same time by the BPEL engine. A <property>Flow</property> completes when all of its enclosed activities have completed. + </para> + <para> + Parallel processing is typically used to save time by doing more than one thing at a time and as a result, speed up the process. However, in many situations several tasks can be started at the same time, but one or more tasks may depend on the successful completion of other tasks. This task dependency sequencing is called <emphasis>synchronization</emphasis> and is achieved using <property>Links</property>. + </para> + <para> + For example, a process that handles purchase orders for material goods needs to: + </para> + <orderedlist> + <listitem> + <para> + Calculate the total order price + </para> + </listitem> + <listitem> + <para> + Calculate shipping costs for the order + </para> + </listitem> + <listitem> + <para> + Send a customer invoice + </para> + </listitem> + </orderedlist> + <para> + All of these activities can be started at the same time, however the shipping cost must be finalized before the total order price can be determined, and the invoice can be sent. + </para> + <para> + To create a <property>Link</property>, right-click on the activity that must be completed first (the activity that is the <emphasis>source</emphasis> of the dependency) and select <guimenuitem>Add Link</guimenuitem> from the context menu. Next, move the mouse to the activity in the <property>Flow</property> that depends on this one (the <emphasis>target</emphasis>) and click the left mouse button to create the link. + </para> + <para> + A <property>Link</property> is identified by a name that must be unique within the <property>Flow</property>. The BPEL Designer generates a reasonable default name, but you can change this in its properties. You can also add a test to the <property>Link</property> that defines the conditions for considering an activity to be complete. For example an activity in a <property>Flow</property> may require two pieces of information, provided by other services, in order to continue. Consider the process <property>Flow</property> shown below: + </para> + <figure> + <title>Flow example</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_22.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + In this example, the <emphasis>Billing</emphasis> department can begin preparation of a customer invoice, but it needs to know if sufficient stock is on hand to fulfill the order and if an outside vendor needs to provide the additional quantities ordered. The following condition would enable the <property>Link</property> so that execution can continue for the price calculation and customer invoicing: + </para> + <figure> + <title>Link example</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/BPEL_Designer_23.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + This process is only partially complete though as it does not consider the number of outside vendors, or if the total quantity being ordered can ever be filled. + </para> + </section> + </section> + <section> + <title>Fault Activities</title> + <para> + Fault activities cause the normal process execution flow to jump to a specialized handler, similar to exceptions in modern programming languages. There are five different types of fault activities, described in this section. + </para> + <section> + <title>Exit</title> + <figure> + <title>Exit</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/Fault_Activities_01.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>Exit</property> activity causes the process to immediately terminate. + </para> + </section> + <section> + <title>Throw</title> + <figure> + <title>Throw</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/Fault_Activities_02.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>Throw</property> activity propagates a specified fault to its ancestor <property>Scope</property>, or the process itself. + </para> + </section> + <section> + <title>Rethrow</title> + <figure> + <title>Rethrow</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/Fault_Activities_03.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + A <property>Rethrow</property> activity can only be used inside a fault handler. It is used to propagate the fault that was caught by the handler, using the original fault data. + </para> + </section> + <section> + <title>Compensate</title> + <figure> + <title>Compensate</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/Fault_Activities_04.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>Compensate</property> activity is used to invoke a compensation handler. This activity can only be used within a fault handler, compensation handler or termination handler. + </para> + </section> + <section> + <title>CompensateScope</title> + <figure> + <title>CompensateScope</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/Fault_Activities_05.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The <property>CompensateScope</property> activity is used to invoke a compensation handler in the enclosing <property>Scope</property>. This activity can only be used within a fault handler, compensation handler or termination handler. + </para> + </section> + </section> + <section> + <title>Faulot, compensation, termination and event handlers</title> + <para> + Handlers allow a BPEL process to recover from exception conditions. Exception conditions include: a timeout waiting for a response from a partner service, invalid or missing message data, a fault condition returned by a service. There are four types of handlers: + </para> + <itemizedlist> + <listitem> + <para> + Fault handler <inlinemediaobject> + <imageobject> + <imagedata fileref="images/reference/Handlers_01.png"/> + </imageobject> + </inlinemediaobject>: Executed when a fauly is thrown by an activity. + </para> + </listitem> + <listitem> + <para> + Compensation handler <inlinemediaobject> + <imageobject> + <imagedata fileref="images/reference/Handlers_02.png"/> + </imageobject> + </inlinemediaobject>: Executed when the BPEL process encounters a <property>Compensate</property> or <property>CompensateScope</property> activity. + </para> + </listitem> + <listitem> + <para> + Temination handler <inlinemediaobject> + <imageobject> + <imagedata fileref="images/reference/Handlers_03.png"/> + </imageobject> + </inlinemediaobject>: Executed if a <property>Scope</property> is forced to terminate early. + </para> + </listitem> + <listitem> + <para> + Event handler <inlinemediaobject> + <imageobject> + <imagedata fileref="images/reference/Handlers_04.png"/> + </imageobject> + </inlinemediaobject>: Executed for events include the receipt of a message and a timer expiration. + </para> + </listitem> + </itemizedlist> + <para> + Handlers are defined for the process or for certain activities. To create a new handler right-click an activity and select the desired handler from its context menu. The BPEL Designer will generate a skeleton of the handler within a collapsible window that is attached to the activity. The figure below illustrates all of the different types of handlers in their fully expanded view. The handler windows can be collapsed and expanded by clicking on their respective icon. + </para> + <figure> + <title>Handlers overview</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/Handlers_05.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + The behavior of handlers and the order of exception processing is complex and beyond the scope of this document. Refer to the OASIS WS-BPEL 2.0 specification at <ulink url="http://docs.oasis-open.org/wsbpel/2.0/wsbpel-v2.0.html">... for more information. + </para> + <section> + <title>Process-level Handlers</title> + <figure> + <title>Start activity with handlers</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/Handlers_06.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + Fault and event handlers can be defined for the process by right-clicking the <property>Start</property> activity and selecting the desired handler from the context menu. + </para> + </section> + <section> + <title>Scope-level handlers</title> + <para> + A <property>Scope</property> may have any handler. Since <property>Scopes</property> can be nested, each level can define its own set of handlers. Events that are not caught and processed by a handler in an inner <property>Scope</property>, will be propagated to its ancestors. + </para> + </section> + <section> + <title>Activity-level handlers</title> + <para> + Only the <property>Invoke</property> activity can define handlers. The handlers available to it are the fault and compensation handlers. + </para> + </section> + </section> + <section> + <title>Correlation Sets</title> + <para> + Correlation sets are used to identify ongoing conversations between a client and the BPEL process. Typically, a correlation is an element in a message that uniquely identifies the conversation between client and service; for example, an Order ID or Social Security Number. This also identifies a specific process instance being managed by the BPEL engine. + </para> + <para> + In many cases a single element of a message is not enough to make it unique, so correlations can be defined as composites of several fields. Since a conversation can involve many different types of messages. Different correlations will need to be defined for each message type. + </para> + <para> + To create a correlation for a messaging activity (for example: <property>Invoke</property>, <property>Receive</property>, <property>Reply</property>), select the activity and then click <guibutton>Add</guibutton> on the <guilabel>Correlation Detail</guilabel> property tab. This will display the <guilabel>Select a Property</guilabel> dialog. + </para> + <figure> + <title>Select a Property</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/Handlers_07.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + You canselect an existing property defined in the WSDL or click <guibutton>New</guibutton> to create a new WSDL property, which will display the <guilabel>Create Message Property</guilabel> dialog. + </para> + <figure> + <title>Create Message Property</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/Handlers_08.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + Enter a name for the new WSDL property and its type. Either an XSD simple type or an XML Schema element. + </para> + <para> + Next, click the <guibutton>Browse”</guibutton> button to select a type. This will display the <guilabel>Type Selection</guilabel> dialog. + </para> + <para> + Click <guilabel>New</guilabel> in the <guilabel>Aliases</guilabel> section to create a new WSDL property alias. + </para> + <figure> + <title>Create Property Alias</title> + <mediaobject> + <imageobject> + <imagedata fileref="images/reference/Handlers_09.png"/> + </imageobject> + </mediaobject> + </figure> + <para> + Select either the <guilabel>Message Type</guilabel>, XSD <guilabel>Simple Type</guilabel> or XML scheme <guilabel>Element</guilabel> radio button and click <guibutton>Browse</guibutton> to select its type. Then click <guibutton>OK</guibutton>. + </para> + </section> + </section> </section> </chapter>