XSLT 1.0 grouping

Question

我有这样的xml：

<?xml version="1.0" encoding="UTF-8"?>
<Returns>
 <Row>
  <Application>
   app1
  </Application>
  <Component>
   comp1
  </Component>
  <Version>
   1
  </Version>
 </Row>
 <Row>
  <Application>
   app1
  </Application>
  <Component>
   comp2
  </Component>
  <Version>
   1
  </Version>
 </Row>
 <Row>
  <Application>
   app1
  </Application>
  <Component>
   comp1
  </Component>
  <Version>
   2
  </Version>
 </Row>
 <Row>
  <Application>
   app1
  </Application>
  <Component>
   comp2
  </Component>
  <Version>
   2
  </Version>
 </Row>
 <Row>
  <Application>
   app2
  </Application>
  <Component>
   comp1
  </Component>
  <Version>
   1
  </Version>
 </Row>
  <Row>
  <Application>
   app2
  </Application>
  <Component>
   comp2
  </Component>
  <Version>
   1
  </Version>
 </Row>
  <Row>
  <Application>
   app2
  </Application>
  <Component>
   comp1
  </Component>
  <Version>
   2
  </Version>
 </Row>
  <Row>
  <Application>
   app2
  </Application>
  <Component>
   comp2
  </Component>
  <Version>
   2
  </Version>
 </Row>
</Returns>

我需要将其转换为这样的东西：

    <?xml version="1.0" encoding="UTF-8"?>
<Components>
   <Component application="app1" version="2" name="comp1"/>
   <Component application="app1" version="2" name="comp2"/>
   <Component application="app2" version="2" name="comp1"/>
   <Component application="app2" version="2" name="comp2"/>
</Components>

目标是仅显示属于每个应用程序的最新版本的组件。

我编写了使用Muenchian分组的XSL模板：

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes" />
<xsl:key name="application" match="Row" use="Application" />
<xsl:template match="Returns">
    <Components>
        <xsl:apply-templates select="Row[generate-id(.)=generate-id(key('application',Application)[1])]">
        </xsl:apply-templates>
    </Components>
</xsl:template>
 <xsl:template match="Row">
        <xsl:for-each select="key('application', Application)">
                    <xsl:sort select="Version" order="descending"/>
                  <xsl:for-each select="Version">
                    <Component application="{normalize-space(../Application)}" version="{normalize-space(current())}" name="{normalize-space(../Component)}"></Component>                      
                 </xsl:for-each>
        </xsl:for-each>
</xsl:template>

现在我得到了此输出：

<?xml version="1.0" encoding="UTF-8"?>
<Components>
   <Component application="app1" version="2" name="comp1"/>
   <Component application="app1" version="2" name="comp2"/>
   <Component application="app1" version="1" name="comp1"/>
   <Component application="app1" version="1" name="comp2"/>
   <Component application="app2" version="2" name="comp1"/>
   <Component application="app2" version="2" name="comp2"/>
   <Component application="app2" version="1" name="comp1"/>
   <Component application="app2" version="1" name="comp2"/>
</Components>

如何过滤组件以仅获取属于同一应用程序的最新版本的组件？

Answer 1

在模板中匹配行（对于每个不同的"应用程序"），您可能需要添加一个变量，其中包含最新版本的值对于当前组。XSLT 1.0中没有可用的"最大"功能，因此您必须像这样做

    <xsl:variable name="Version">
       <xsl:for-each select="key('application', Application)">
           <xsl:sort select="Version" order="descending"/>
           <xsl:if test="position() = 1">
               <xsl:value-of select="Version" />
           </xsl:if>
        </xsl:for-each>
    </xsl:variable>

然后，您可以在当前组中获得最新版本的元素，例如so

<xsl:for-each select="key('application', Application)[Version=$Version]">

尝试此XSLT

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes" />
<xsl:key name="application" match="Row" use="Application" />
<xsl:template match="Returns">
    <Components>
        <xsl:apply-templates select="Row[generate-id(.)=generate-id(key('application',Application)[1])]">
        </xsl:apply-templates>
    </Components>
</xsl:template>
 <xsl:template match="Row">
        <xsl:variable name="Version">
           <xsl:for-each select="key('application', Application)">
               <xsl:sort select="Version" order="descending"/>
               <xsl:if test="position() = 1">
                   <xsl:value-of select="Version" />
               </xsl:if>
            </xsl:for-each>
        </xsl:variable>
        <xsl:for-each select="key('application', Application)[Version=$Version]">
            <Component application="{normalize-space(Application)}" version="{normalize-space(Version)}" name="{normalize-space(Component)}"></Component>                      
        </xsl:for-each>
</xsl:template>
</xsl:stylesheet>

这会产生以下输出

<Components>
  <Component application="app1" version="2" name="comp1"/>
  <Component application="app1" version="2" name="comp2"/>
  <Component application="app2" version="2" name="comp1"/>
  <Component application="app2" version="2" name="comp2"/>
</Components>