The WS-BPEL XPath Expression Editor is a NetBeans plug-in editor for building XPath expressions which are used in various WS-BPEL elements. The WS-BPEL XPath Expression Editor allows the user to build XPath expressions in a WYSWYG way. It works on XML Schema (XSD) trees to generator XPath expressions.

WS-BPEL 2.0 Language Background

The WS-BPEL 2.0 language supports XPath 1.0 for defining expressions in various WS-BPEL constructs. WS-BPEL uses several types of expressions. The kinds of expressions used are as follows (relevant usage contexts are listed in parentheses):

• Boolean-valued expressions (transition conditions, join conditions, while conditions, and if conditions)
• Deadline-valued expressions ("until" expression of onAlarm and wait)
• Duration-valued expressions ("for" expression of onAlarm and wait, "repeatEvery" expression of onAlarm)
• General expressions (assignment)

WS-BPEL 2.0 Language Supported Elements

The following WS-BPEL 2.0 language elements are supported by the WS-BPEL XPath Expression Editor:

• Boolean Expressions

• <conditon> element of <while>
• <condition> element of <if> and <elseif>
• <condition> element of <repeatUntil>
• <joinCondition> element of <targets>
• <transitionCondition> element of <source>
• Deadline Expressions
• <for> element of <onAlarm>
• <for> element of <wait>
• <for> element of <repeatEvery>
• Duration Expressions
• <until> element of <onAlarm>
• <until> element of <wait>
• General Expressions
• Inside <from> element of <copy>
• Inside <to> element of <copy>

XPath 1.0 Support

The WS-BPEL XPath Expression Editor supports the XPath 1.0 specification. (See Xpath specification for more information of how operators are evaluated)

Usage Scenarios

The following details some use-case scenarios in which the WS-BPEL XPath Expression Editor can help:

1. Creating a variable to variable assignment expression

 The user can create variable to variable assignments which will generate a <copy> with XPath expressions under the selected assign activity.

 e.g.,

<copy>

    <from variable="sayHello_Input"/>

    <to variable="sayHello_Output"/>

</copy>

2. Create a part to part assignment expression

The user can create part to part assignments which will generate a <copy> with XPath expressions under selected assign activity.

e.g.,

<copy>

    <from variable="sayHello_Input" part="result"/>

    <to variable="sayHello_Output" part="body"/>

</copy>

3. Create an XSD element-to-element assignment expression

The user can create an XSD element to XSD element assignment which will generate a <copy> with XPath expressions under the selected assign activity.

e.g.,

<copy>

    <from>$sayHello_Input.result/long</from>

    <to>$sayHello_Input.result/long</to>

</copy>

4. Create an XSD attribute-to-attribute assignment expression

The user can create an XSD attribute to XSD attribute assignment which will generate a <copy> with XPath expressions under the selected assign activity.

e.g.,

<copy>

    <from>$sayHello_Input.result/shiporder/@orderid</from>

    <to>$sayHello_Output.body/shiporder/@orderid</to>

</copy>

5. Create an expression using an XPath operator

The user can use any XPath 1.0 supported operator in the XPath expression editor.

e.g.,

<copy>

    <from>($sayHello_Input.result/int + $sayHello_Input.result/long) </from>

    <to>$sayHello_Output.body/double</to>

</copy>

6. Create an expression using any XPath core function

The user can use any XPath 1.0 supported core function in the XPath expression editor.

e.g.,

<copy>

    <from>concat($sayHello_Input.result/shiporder/shipto/name, $sayHello_Input.result/shiporder/shipto/address)</from>

    <to>$sayHello_Output.body/shiporder/shipto/name</to>

</copy>

7. Create an expression using literal

The user can define expressions using string literals, number literals and duration literals.

e.g.,

<copy>

    <from>&apos;Menlo Park&apos;</from>

    <to>$sayHello_Output.body/shiporder[1]/shipto/city</to>

</copy>

<copy>

    <from>1234</from>

    <to>$sayHello_Output.body/shiporder[1]/@orderid</to>

</copy>

<copy>

    <from>&apos;P2006Y5M10DT4H9M7S&apos;</from>

    <to>$sayHello_Output.body/dateTime</to>

</copy>

8. Create an XPath predicate

The user can define XPath predicate expressions.

e.g.,

$sayHello_Input.result/shiporder[5]

9. Use a predicate in assignment

The user can use a predicate in assignment.

e.g.,

<copy>

    <from>$sayHello_Input.result/shiporder[5]</from>

    <to>$sayHello_Output.body/shiporder</to>

</copy>

10. Create a Boolean expression

The user can create a Boolean expression used in various WS-BPEL elements which require Boolean conditional expressions. (for e.g., <while>)

e.g.,

<condition> $sayHello_Input.result/shiporder/shipto/country = &apos;US&apos;  </condition>

11. Create a Duration expression

The user can create a Duration expression used in various WS-BPEL elements which require Duration expressions. (e.g., <wait>)

e.g.,

<for>&apos;P2006Y1M30DT3M13S&apos;</for>

12. Create a Deadline expression

The user can create a Deadline expression used in various WS-BPEL elements which require Deadline expressions. (e.g., <wait> )

e.g.,

<until>$sayHello_Input.result/dateTime</until>

User Interface Interactions

The WS-BPEL XPath Expression Editor is launched based on the current selected WS-BPEL element in WS-BPEL editor. If there is currently a selected WS-BPEL element which requires the WS-BPEL XPath Expression Editor, then the editor is shown in the NetBeans IDE in the bottom pane.