XPathString

XPathString - Get Value With XPath

The XPathString component gets a node's value from the input XML stream as specified by the XPath.

Stream Information

Input	Format	XML
Input	Number of Inputs	1
Output	Format	XML
Output	Description	The input stream is copied to the output stream.

Component Properties

Name	Data Type	Mapping	Description
XPath	category	In	The XPath statement. XPath can specify XPath generated automatically by the selection from the tree of XML by the use of the XPath Expression editor for the property. For details, refer the topic XPath Expression Editor below. Also, XPath is set as a stream variable automatically. The XPath can used by next mapper component as a stream variable. For details of stream variable, refer the help of Stream Variables in Flow Service manual. Name The field name to which the retrieved data will be set. XPath XPath The XPath statement. ASTERIA variables can be referenced in this statement. The input stream's Namespace is the Namespace by which the statement is applied. Type The output's data type. The output data is converted from the String value retrieved from the input XML. An Exception will occur if the retrieved data can not be converted to the selected data type.

Name

Data Type

Mapping

Description

XPath

Loop

This component cannot be the starting point for a loop.

Transaction

Commit	Do nothing
Rollback	Do nothing

Exceptions

Type	Parameter	Stream for error handling flow	Error Code	Description
Exception	None	This component's input stream	-	The XPath is invalid.
Exception	None	This component's input stream	-	Can not convert the retrieved data to the selected output field's data type.

How to use Variables

Flow variables and system variables can be referenced in the XPath statement.
External variable set can not be used.

Flow Variables	$flow.variableName
System Variables	$system.variableName

XPath Expression Editor

XPath Expression Editor is for helping when you input the Xpath expression. Select the node from the tree, then the XPath of that node will be set to the property.
Click "..." in the right of the field that specifies XPath, then it starts.

Tree

The field definition of the target stream for XPath is displayed in the tree. For instance, the target input stream in the XPathNodeset component for XPath and the field definition is displayed. When the link is not connected with the input side of the component, nothing is displayed in the input stream in the initial state when the field definition is not done.

Reference sample button

Arbitrary XML is read, and the structure can be displayed in the tree. Moreover, the value of the node selected with the tree (attribute value or element content) is displayed in the value tab, and it can be used to specify the conditional expression.

If clicking the "Reference sample" button, "Open" dialog box is displayed. Then, select XML to be read.
The structure of XML is analyzed and it is displayed in the tree.

"Save sample instance to xfp" checkbox

Read XML is preserved in the xfp file (project file) when "The sample is preserved in xfp" check box is turned on when XML is read from the "Reference sample", and that XML can be referred to when the xfp file will be opened next time. As for read XML, when the check box is off, the editor is not preserved. To use it next time, it reads from "Reference sample" button again.

Notice:Sample XML is not information necessary for the execution of the component. Please preserve only the stage of development and the test so that the size of the file of the xfp file (project file) may grow when big XML of the size of the file is preserved, and the time that hangs to preservation and the compilation may increase, too.

Set XPath

When the node is selected with the tree, the XPath is displayed in "Selected path" field. When the button of "Copy selected path to XPath" is clicked, the path is copied onto the "XPath" field. "XPath" field can be edited. If you want to specify complex XPath, you can edit the value directly there.

Set variables to conditional expression

The variable that can be used by the component like the flow variable and the local variable, etc. is listed in the variable tab.
When path selected with the tree composes a part of XPath, the comparison with the variable can be added to XPath with "Add parameter to selected path" button.

Example

XPath	/School/Class/Student
Selected path	/School/Class/@name
Variable	$flow.var1
XPath after adding the variable	/School/Class[@name=$flow.var1]/Student

Because the selected path "/School/Class/@name" is ancestor of "/School/Class/Student", it can be used as conditional expression. If the selected path is not related the XPath like "/School/Class/Teacher/@name", the button is disabled.

Set the value to conditional expression

When sample XML is used, the value actually set to the selected path is listed in the value tab. When the selected path with the tree composes a part of XPath, the comparison with the value can be added to XPath with "Add parameter to selected path" button.

Example

XPath	/School/Class/Student
Selected path	/School/Class/@name
Value	Class A
XPath after adding the condition	/School/Class[@name="Class A"]/Student

The rule that can add the condition is the same as the case of the variable.