xslt-2.0 - 为什么 Saxon 将结果文档 URI 评估为相同？

Question

我的 XSL 源文件是这样的

<Topology>
<Environment>
    <Id>test</Id>
    <Machines>
        <Machine>
            <Id>machine1</Id>
            <modules>
                <module>m1</module>
                <module>m2</module>
            </modules>
        </Machine>
    </Machines>
</Environment>
<Environment>
    <Id>production</Id>
    <Machines>
        <Machine>
            <Id>machine1</Id>
            <modules>
                <module>m1</module>
                <module>m2</module>
            </modules>
        </Machine>
        <Machine>
            <Id>machine2</Id>
            <modules>
                <module>m3</module>
                <module>m4</module>
            </modules>
        </Machine>
    </Machines>
</Environment>
</Topology>

我想为每台机器创建一个结果文档，所以我使用以下样式表，将 modelDir 作为结果文档的路径作为参数。

<xsl:output method="xml" version="1.0" encoding="UTF-8" 
            indent="yes" name="myXML" doctype-system="http://java.sun.com/dtd/properties.dtd"/>

<xsl:template match="/">
    <xsl:for-each-group select="/Topology/Environment/Machines/Machine" group-by="Id">

        <xsl:variable name="machine" select="Id"/>
        <xsl:variable name="filename" select="concat($modelDir,$machine,'.xml')" />

        <xsl:message terminate="no">Writing machine description to <xsl:value-of select="$filename"/></xsl:message>

        <xsl:result-document href="$filename" format="myXML">

            <xsl:variable name="currentMachine" select="Id"/>
            <xsl:for-each select="current-group()/LogicalHosts/LogicalHost">
                <xsl:variable name="environment" select="normalize-space(../../../../Id)"/>
                <xsl:message terminate="no">Module <xsl:value-of select="."/> for <xsl:value-of select="$environment"/></xsl:message>
            </xsl:for-each>

        </xsl:result-document>

     </xsl:for-each-group>
</xsl:template>

正如我的消息所显示的那样，这似乎工作正常 - 如果 saxon 不会将结果文档的 URI 评估为相同并因此给出以下输出。

Writing machine description to target/build/model/m1.xml
Module m1 for test
Module m2 for test
Module m1 for production
Module m2 for production
Writing machine description to target/build/model/m2.xml
Error at xsl:result-document on line 29 of file:/C:/Projekte/.../machine.xsl:
  XTDE1490: Cannot write more than one result document to the same URI, or write to a URI
  that has been read:
  file:/C:/Projekte/.../$filename
file:/C:/Projekte/.../machine.xsl(29,-1) : here Cannot write more than one result document to the same URI, or write to a URI that has been read: file:/C:/Projekte/.../$filename
; SystemID: file:/C:/Projekte/.../machine.xsl; Line#: 29; Column#: -1
net.sf.saxon.trans.DynamicError: Cannot write more than one result document to the same URI, or write to a URI that has been read: file:/C:/Projekte/.../$filename
    at net.sf.saxon.instruct.ResultDocument.processLeavingTail(ResultDocument.java:300)
    at net.sf.saxon.instruct.Block.processLeavingTail(Block.java:365)
    at net.sf.saxon.instruct.Instruction.process(Instruction.java:91)

关于如何解决这个问题有什么想法吗？

Answer 1

您正在为 @file 指定一个变量 $filename，但没有包装在 {} 中，因此它正在评估它作为每次都是字符串“$filename”(这是相同的 URI，因此是错误)。

您需要它来评估为 Attribute Value Template .

<xsl:result-document href="{$filename}" format="myXML">