6 Oracle CEP IDE for Eclipse and the Event Processing Network

6.1.1 How to Open the EPN Editor from a Project Folder

You can open the EPN Editor from the Eclipse project folder of an Oracle CEP application. Alternatively, you can open the EPN Editor from a context or configuration file (see Section 6.1.2, "How to Open the EPN Editor from a Context or Configuration File").

To open the EPN Editor from a project:

1. Launch the Oracle CEP IDE for Eclipse.

2. Open your Oracle CEP project in the Project Explorer.

3. Right-click the project folder and select Open EPN Editor as Figure 6-1 shows.

   Figure 6-1 Opening the EPN Editor from a Project

   
   Description of "Figure 6-1 Opening the EPN Editor from a Project"
   
   

   The EPN Editor opens in a tab named EPN:PROJECT-NAME, where PROJECT-NAME is the name of your Oracle CEP project, as Figure 6-2 shows.

   Figure 6-2 EPN Editor

   
   Description of "Figure 6-2 EPN Editor"
   
   

6.1.2 How to Open the EPN Editor from a Context or Configuration File

You can open the EPN Editor from a Spring context file or an Oracle CEP server configuration file in an Oracle CEP application. Alternatively, you can open the EPN Editor from a context or configuration file (see Section 6.1.1, "How to Open the EPN Editor from a Project Folder")

To open the EPN Editor from a context or configuration file:

1. Launch the Oracle CEP IDE for Eclipse.

2. Open your Oracle CEP project in the Project Explorer.

3. Right-click a context or configuration file and select Open in EPN Editor as Figure 6-3 shows.

   Figure 6-3 Opening the EPN Editor from a Context or Configuration File

   
   Description of "Figure 6-3 Opening the EPN Editor from a Context or Configuration File"
   
   

   The EPN Editor opens in a tab named EPN:PROJECT-NAME, where PROJECT-NAME is the name of your Oracle CEP project, as Figure 6-4 shows.

   Figure 6-4 EPN Editor

   
   Description of "Figure 6-4 EPN Editor"
   
   

6.2.1 Flow Representation

The primary display in the editor is of the flow inside the application as Figure 6-5 shows.

Figure 6-5 EPN Flow Representation

Description of "Figure 6-5 EPN Flow Representation"

The EPN is composed of nodes connected by links and streams. Nodes are of various types including adapter, processor, database table, bean, and cache. For more information on the graphic notation the EPN Editor uses on nodes, links, and streams, see:

• Section 6.2.7, "Configuration Badging"

• Section 6.2.8, "Link Specification Location Indicator"

6.2.2 Filtering

Although you often specify your EPN in a single assembly file, you may specify an EPN across multiple assembly files.

By default the EPN Editor shows the EPN for a single Oracle CEP application bundle with the information combined from all files.

To see the network for a single assembly file simply select that file from the Filter pull-down menu as Figure 6-6 shows.

Figure 6-6 Filtering the EPN by Assembly File

Description of "Figure 6-6 Filtering the EPN by Assembly File"

When editing an EPN, the assembly file shown in the EPN Editor filter is the assembly file to which new nodes will be added. If the EPN Editor filter is set to Full EPN then the first assembly file in the filter list will be the file to which new nodes will be added. Existing nodes will be edited in or deleted from the assembly file in which they are defined.

If the assembly file the EPN Editor edits is open in an Eclipse source editor, then the edits will be made to the editor for that open file. In this case, you will need to save changes to the open editor before the changes appear in the file on disk.

If the assembly file the EPN Editor edits is not open in an Eclipse source editor, then the edits are immediately applied to the file on disk.

For more information, see Section 4.3, "Creating EPN Assembly Files".

6.2.3 Zooming

You can change the zoom level of the EPN Editor by entering a percent value into the zoom field or selecting a value from the zoom field pull-down menu as Figure 6-7 shows. To fit the EPN into the current EPN Editor window, select Fit to Window.

Figure 6-7 Zoom Level

Description of "Figure 6-7 Zoom Level"

6.2.4 Layout

You can optimize and simplify the EPN layout by clicking Layout EPN as Figure 6-8 shows.

Figure 6-8 Optimize Layout

Description of "Figure 6-8 Optimize Layout"

6.2.5 Showing and Hiding Unconnected Beans

You can also filter out <bean> elements with no references in the EPN. Clicking Show/Hide Unconnected Beans will toggle the visibility of such beans as Figure 6-9 shows. For more information, see Section 6.4.3, "Laying Out Nodes".

Figure 6-9 Show/Hide Unconnected Beans

Description of "Figure 6-9 Show/Hide Unconnected Beans"

6.2.6 Printing and Exporting to an Image

You can export the EPN Editor view to an image file by clicking Export to Image as Figure 6-10 shows. You can export the image as a .bmp, .gif, .jpg, or .png file.

Figure 6-10 Exporting the EPN as an Image File

Description of "Figure 6-10 Exporting the EPN as an Image File"

You can print the EPN Editor view by clicking Print as Figure 6-11 shows.

Figure 6-11 Printing the EPN

Description of "Figure 6-11 Printing the EPN"

6.2.7 Configuration Badging

Nodes that have configuration information in one of the configuration files in the META-INF/wlevs directories are badged with an indicator on the bottom right as Figure 6-12 shows.

Figure 6-12 Configuration Badging

Description of "Figure 6-12 Configuration Badging"

Nodes with this badge will also have the Go To Configuration Source context menu item.

6.2.8 Link Specification Location Indicator

When working with streams, you can specify a link in the assembly file as a:

• source element in the downstream node.

• listener element in the upstream node

A circle on the line indicates where a particular link is specified in the assembly file.

Figure 6-13 shows an example in which the link is specified as a source element on the downstream node outStream so the circle is next to the outStream node. Figure 6-14 shows the corresponding assembly file.

Figure 6-13 Link Source

Description of "Figure 6-13 Link Source"

Figure 6-14 Link Source Assembly File

Description of "Figure 6-14 Link Source Assembly File"

Figure 6-15 shows an example in which the link is specified as a listener element in the upstream node algoTradingProcessor so the circle is next to the algoTradingProcessor node. Figure 6-16 shows the corresponding assembly file.

Figure 6-15 Link Listener

Description of "Figure 6-15 Link Listener"

Figure 6-16 Link Listener Assembly File

Description of "Figure 6-16 Link Listener Assembly File"

6.2.9 Nested Stages

When you define a child node within a parent node, the child node is said to be nested. Only the parent node can specify the child node as a listener. You can drag references from a nested element, but not to them. For more information, see Section 6.4.2, "Connecting Nodes".

Consider the EPN that Figure 6-17 shows. Example 6-1 shows the EPN assembly source for this EPN. Note that the HelloWorldBean is nested within the helloworldOutputChannel. As a result, it appears within a box in the EPN diagram. Only the parent helloworldOutputChannel may specify the nested bean as a listener.

Figure 6-17 EPN With Nested Bean

Description of "Figure 6-17 EPN With Nested Bean"

<wlevs:adapter id="helloworldAdapter"
 class="com.bea.wlevs.adapter.example.helloworld.HelloWorldAdapter" >
    <wlevs:instance-property name="message" value="HelloWorld - the current time is:"/>
</wlevs:adapter>

<wlevs:channel id="helloworldInputChannel" event-type="HelloWorldEvent" >
    <wlevs:listener ref="helloworldProcessor"/>
    <wlevs:source ref="helloworldAdapter"/>
</wlevs:channel>

<wlevs:processor id="helloworldProcessor" />

<wlevs:channel id="helloworldOutputChannel" event-type="HelloWorldEvent" advertise="true">
    <wlevs:listener>
        <bean class="com.bea.wlevs.example.helloworld.HelloWorldBean"/>
    </wlevs:listener>
    <wlevs:source ref="helloworldProcessor"/>
</wlevs:channel>

Alternatively, you can define this EPN so that all nodes are nested as Figure 6-18 shows. Example 6-2 shows the EPN assembly source for this EPN. Note that all the nodes are nested and as a result, all nodes appear within a box in the EPN diagram. The helloworldAdapter is the outermost parent node and does not appear within a box in the EPN diagram.

Figure 6-18 EPN With all Nodes Nested

Description of "Figure 6-18 EPN With all Nodes Nested"

<wlevs:adapter id="helloworldAdapter" class="com.bea.wlevs.adapter.example.helloworld.HelloWorldAdapter" >
    <wlevs:instance-property name="message" value="HelloWorld - the current time is:"/>
    <wlevs:listener>
        <wlevs:channel id="helloworldInputChannel" event-type="HelloWorldEvent" >
            <wlevs:listener>
                <wlevs:processor id="helloworldProcessor">
                    <wlevs:listener>
                        <wlevs:channel id="helloworldOutputChannel" event-type="HelloWorldEvent">
                            <wlevs:listener>
                                <bean class="com.bea.wlevs.example.helloworld.HelloWorldBean"/>
                            </wlevs:listener>
                        </wlevs:channel>
                    </wlevs:listener>
                </wlevs:processor>
            </wlevs:listener>
        </wlevs:channel>
    </wlevs:listener>
</wlevs:adapter>

6.2.10 Event Type Repository Editor

You can create and edit JavaBean and tuple event types using the event type repository editor.

To open the event type repository editor, click on the Event Types tab in the EPN editor as Figure 6-19 shows.

Figure 6-19 Event Type Repository Editor

Description of "Figure 6-19 Event Type Repository Editor"

For more information, see:

• Section 2.2.2, "How to Create an Oracle CEP Event Type as a JavaBean Using the Event Type Repository Editor"

• Section 2.3.1, "How to Create an Oracle CEP Event Type as a Tuple Using the Event Type Repository Editor"

For information on the other types of events you can create, see Section 1.1.2, "Oracle CEP Event Types".

6.3.1 Moving the Canvas

To move the EPN canvas without using the horizontal and vertical scroll bars, you can use any of the following options:

• Position the cursor on the canvas, hold down the middle mouse button, and drag.

• Hold down the space bar and click and drag the canvas.

• In the Overview view, click in the highlight box and drag.

6.3.2 Shortcuts to Component Configuration and EPN Assembly Files

If a node has a configuration object associated with it, then double-clicking that node will open the component configuration file where that node's behavior is defined.

Otherwise, double-clicking that node will open the EPN assembly file (the Spring context file) where that node is defined.

A configuration badge will be shown on nodes with associated configuration objects as shown in Figure 6-20.

Figure 6-20 Node with Configuration Badge

Description of "Figure 6-20 Node with Configuration Badge"

For more information, see:

• Section 6.2.7, "Configuration Badging"

• Section 6.3.3, "Hyperlinking"

6.3.3 Hyperlinking

When editing a component configuration file, EPN assembly file, or Oracle CQL statement, hold down the Ctrl key to turn on hyperlinking. Using hyperlinking, you can easily move between assembly and configuration files and follow reference IDs to jump to bean implementation classes.

This section describes:

• Section 6.3.3.1, "Hyperlinking in Component Configuration and EPN Assembly Files"

• Section 6.3.3.2, "Hyperlinking in Oracle CQL Statements"

6.3.3.1 Hyperlinking in Component Configuration and EPN Assembly Files

Figure 6-21 shows a component configuration file with the cursor over the value of a processor element name child element while holding down the Ctrl key. The name value has an underline to indicate it is a hyperlink. Click this link to jump to the corresponding element in the EPN assembly file as Figure 6-22 shows.

Figure 6-21 Component Configuration File: Hyperlinking to EPN Assembly File

Description of "Figure 6-21 Component Configuration File: Hyperlinking to EPN Assembly File"

Similarly, hovering over the wlevs:processor element id child element value filterFanoutProcessor while holding down the Ctrl key allows you to hyperlink back to the component configuration file.

Figure 6-22 EPN Assembly File: Hyperlinking to Component Configuration File

Description of "Figure 6-22 EPN Assembly File: Hyperlinking to Component Configuration File "

6.3.3.2 Hyperlinking in Oracle CQL Statements

Figure 6-23 shows a component configuration file with the cursor over an event attribute while holding down the Ctrl key. The fromRate attribute has an underline to indicate it is a hyperlink. Click this link to jump to the corresponding event definition in the EPN assembly file as Figure 6-24 shows.

Note:

Hyperlinking in Oracle SQL statements is designed for simple use cases and may not work as expected in more complex implementations.

Figure 6-23 Oracle CQL Statement: Event Schema

Description of "Figure 6-23 Oracle CQL Statement: Event Schema"

Figure 6-24 Corresponding Event Definition in EPN Assembly File

Description of "Figure 6-24 Corresponding Event Definition in EPN Assembly File"

Similarly, you can Ctrl-click the FxQuoteStream channel in the Oracle CQL statement that Figure 6-23 shows to jump to the channel's definition. This is applicable wherever references to external objects are present in a Oracle CQL statement.

6.3.4 Context Menus

Each node on the EPN Editor has a group of context menu items that provide convenient access to various node-specific functions. Right-click the node to display its context menu.

Depending on the node type, you can use the EPN Editor context menu to select from the following options:

• Go to Configuration Source: opens the corresponding component configuration file and positions the cursor in the appropriate element. You can use hyperlinking to quickly move from this file to the corresponding EPN assembly file. For more information, see Section 6.3.3, "Hyperlinking".

• Go to Assembly Source: opens the corresponding EPN assembly file and positions the cursor in the appropriate element. You can use hyperlinking to quickly move from this file to the corresponding component configuration file. For more information, see Section 6.3.3, "Hyperlinking"

• Go to Java Source: opens the corresponding Java source file for this component.

• Delete: deletes the component from both the EPN assembly file and component configuration file (if applicable).

• Rename: allows you to change the name of the component. The name is updated in both the EPN assembly file and component configuration file (if applicable).

• Help: displays context sensitive help for the component.

Note that these navigation options will become disabled when a corresponding source artifact cannot be found. For example, if an adapter does not have a corresponding entry in a configuration XML file, its Go to Configuration Source menu item will be greyed out.

6.3.5 Browsing Oracle CEP Types

A typical Oracle CEP project contains many instances of Oracle CEP types such as adapters, channels, processors, event beans. In a large, complex Oracle CEP project, it can be a challenge to locate a particular instance. The Oracle CEP IDE for Eclipse provides an Oracle CEP type browser that you can use to quickly locate instances of any Oracle CEP type.

6.4.1 Creating Nodes

When adding new nodes to an EPN using the EPN editor, a new node will appear at the location of the mouse click that was used to show the EPN Editor context menu. You can create any of the nodes that Table 6-2 lists.

Table 6-2 EPN Editor Icons

Node	Description
	Adapter: a node that interfaces an event data source with the EPN or interfaces the EPN with an event data sink. For more information, see: Section 6.4.1.2, "How to Create an Adapter Node" Chapter 7, "Configuring JMS Adapters" Chapter 8, "Configuring HTTP Publish-Subscribe Server Adapters" Chapter 14, "Configuring Custom Adapters" Chapter 25, "Testing Applications With the Load Generator and csvgen Adapter"
	Channel: a node that conveys events between an event data source and an event data sink. For more information, see: Section 6.4.1.1, "How to Create a Basic Node" Chapter 9, "Configuring Channels"
	Processor: a node that executes Oracle CQL or EPL rules on the event data offered to it by one or more channels. For more information, see: Section 6.4.1.3, "How to Create a Processor Node" Chapter 10, "Configuring Oracle CQL Processors" Chapter 11, "Configuring EPL Processors"
	Event Bean: a node similar to a standard Spring bean except that it can be managed by the Oracle CEP management framework and can actively use the capabilities of the Oracle CEP server container. For more information, see: Section 6.4.1.1, "How to Create a Basic Node" Chapter 15, "Configuring Custom Event Beans"
	Spring Bean: a Plain Old Java Object (POJO) node that consumes events. A Spring bean is managed by the Spring framework. For more information, see: Section 6.4.1.1, "How to Create a Basic Node" Chapter 16, "Configuring Custom Spring Beans"
	Cache: a node that provides a temporary storage area for events, created exclusively to improve the overall performance of your Oracle CEP application. For more information, see: Section 6.4.1.1, "How to Create a Basic Node" Chapter 12, "Configuring Caching"
	Table: a node that connects a relational database table to the EPN as an event data source. For more information, see: Section 6.4.1.1, "How to Create a Basic Node" Section 10.3, "Configuring an Oracle CQL Processor Table Source"

The user may not reposition the nodes on the EPN Editor. To refresh the layout of the nodes on the EPN Editor, click the Layout EPN button on the EPN Editor toolbar. For more information, see Section 6.4.3, "Laying Out Nodes".

When a child node is nested within a parent node, its icon appears within a box. For more information, see Section 6.2.9, "Nested Stages".

6.4.2 Connecting Nodes

The nodes in the EPN represent the flow of events through an Event Processing Network of an Oracle CEP application. When a node may forward events to another node in the EPN, the EPN Editor allows you to connect that node visually by dragging a line from the source node to the destination node.

6.4.3 Laying Out Nodes

Certain EPN Editor actions will use the location of the action as the location of the rendered result. For example, when adding new nodes to an EPN using the EPN editor, a new node will appear at the location of the mouse click that was used to show the EPN Editor context menu. The user may not reposition the nodes on the EPN Editor. To refresh the layout of the nodes on the EPN Editor, click the Layout EPN button on the EPN Editor toolbar as Figure 6-46 shows.

Figure 6-46 Laying Out Nodes

Description of "Figure 6-46 Laying Out Nodes"

For more information, see Section 6.2.4, "Layout".

6.4.4 Renaming Nodes

Most node types support a rename operation that will change all references to the node across both assembly and configuration XML files. You can select Rename from the node's context menu as Figure 6-47 shows.

Figure 6-47 Renaming Nodes

Description of "Figure 6-47 Renaming Nodes"

6.4.5 Deleting Nodes

You may delete most nodes and connections visible on the EPN Editor using the node's context menu or the Delete key:

• Using the keyboard, select the object you want to delete and then click the Delete key.

• Using the context menu, right-click on the object to show the context menu, then select Delete as Figure 6-48 shows.

  Figure 6-48 Deleting Nodes

  
  Description of "Figure 6-48 Deleting Nodes"
  
  

When deleting a node, the incoming and outgoing connections are also deleted. For example, Figure 6-49 shows the EPN and Figure 6-51 shows the assembly file before deleting the channel node named stream.

Figure 6-49 EPN Before Deleting a Channel Node

Description of "Figure 6-49 EPN Before Deleting a Channel Node"

Figure 6-50 Assembly File Before Deleting a Channel Node

Description of "Figure 6-50 Assembly File Before Deleting a Channel Node"

Figure 6-51 shows the EPN and Figure 6-52 shows the assembly file after deleting this channel node.

Figure 6-51 EPN After Deleting a Channel Node

Description of "Figure 6-51 EPN After Deleting a Channel Node"

Figure 6-52 Assembly File After Deleting a Channel Node

Description of "Figure 6-52 Assembly File After Deleting a Channel Node"