Page Comparison

This page provides information on WSO2 BPS's compliance to the final WS-BPEL 2.0 specification released by This page provides information on WSO2 BPS's compliance to the final WS-BPEL 2.0 specification released by OASIS.

Variable Initialization

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The following types of variants are available for in the <assign> activity.

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From/To-Spec Variants

The <assign> activity copies a type-compatible value from the source ("from-spec") to the destination ("to-spec"), using <copy> element. The from-spec must be one of the following:

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Selects value stored in a BPEL variable

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<to|from variable="BPELVariableName"part="NCName"?><queryqueryLanguage="anyURI"?>?
      queryContent
   </query></to|from>

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|from>

• variable - (required) name of the variable
• part - (optional) if the type of this variable is a WSDL messageType, this attribute may be used to provide the name of a part within that variable. This attribute must not be used when the variable is defined using XML schema types or element.
• <query> element may be used to select a value from the source or target variable or message part. The computed value of the query must be one the following:
  
  • a sigle XML node, for example an attribute or an element
  • test(i. e. a text node, CDATA section, string-valued XPath expression, etc..)

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<frompartnerLink="NCName"endpointReference="myRole|partnerRole"/>
<topartnerLink="NCName"/>

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• partnerLink - name of the partnerLink
• role - the role or "side" of the partnerLink
  
  • myRole - the endpoint reference of the process
  • partnerRole - the partner's endpoint reference

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Allows data manipulation using properties. The property value generated by the from-spec is generated in the same manner as the value returned by the bpel:getVariableProperty() function.

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<to|from variable="BPELVariableName"property="QName"/>

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• variable - name of the variable referenced
• property - name of the property to apply to the variable

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In the Expression Variant, an expression language (typically XPath), is used to calculate a value.

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<to|from expressionLanguage="anyURI"?>expression</from>

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• expressionLanguage - (optional) identifies the expression language.
• expression - the expression ; whose syntax is determined by the expression language.

The computed value of the expression must be one of the following:

• a single XML node, for example, an attribute or an element.
• text(i. e. a text node, CDATA section, string-valued XPath expression, etc.)

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The literal variant allows a literal value to be given as the rvalue.

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<from><literal>literal value</literal></from>

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• literal value - value to be assigned

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Empty Variant

Empty variant exist exists for extensibility purposes; it . It is not supported by WSO2 BPS.

<from|to/>

Insert Variant (

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Non-

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Standard Extension)

Faults

• bpel:invalidVariables - A modified variable does not conform to its schema and the validate flag was is set to yes.
• bpel:selectionFailure - The node(s) selected by a from/to-spec is (are) invalid. This includes cases when the to-spec returns a node that is not an lvalue, when multiple nodes are selected, or when no node is selected.
• bpel:subLanguageExecutionFault - Evaluating the expression (in the expression variant), or the query (in the variable variant) generated generates an error. For example, if when a divide-by-zero is attempted.
• bpel:uninitializedVariable - The variable referenced in the from-spec has is not been initialized.
• bpel:mismatchedAssignmentFailure - The nodes selected by the to-spec and from-spec are not compatible. This For example, this could occur if for example an attempt was made to assign a text node to an element variable, or an element variable was assigned to a message variable.

Examples

• The following assigns a childless element bar in namespace http://example.com to an element-typed variable myFooBarElemVar:

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<assign>
   <copy>
       <from><literalxmlns:foo="http://example.com"

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><foo:bar/

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></literal></from><tovariable="myFooBarElemVar"/>
   </

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copy>
</

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assign>

• The following assigns the string "FooBar" to a string-typed variable myStringVar:

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<assign>
   <copy>
      <from>
         <literal><![CDATA[FooBar]]

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></literal>
      </from>
      <tovariable="myStringVar"/>
   </

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copy>
</

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assign>

• The following assigns the string "" (i.e. the empty string) to a string-typed variable myStringVar:

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<assign> 
   <copy>
      <from>
         <literal/>
      </from>
      <tovariable="myStringVar"/>
   </

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copy>
</

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assign>

• The following illustrates copying one variable (c1) to another (c2) as well as copying a variable part (address part of variable c1) to a variable of compatible element type (c3):

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<assign>
    <copy>
       <fromvariable="c1"/

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>
       <tovariable="c2"/>

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    </copy>
    <copy>
       <from>$c1.address</from>
       <tovariable="c3"/>
    </

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copy>
</

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assign>