Muenchian 分组样式表返回重复的未分组节点

Posted 2023-02-16

【中文标题】Muenchian 分组样式表返回重复的未分组节点

【英文标题】：Muenchian grouping stylesheet returning duplicate ungrouped nodes

【发布时间】：2020-10-24 11:25:39

【问题描述】：

我正在尝试使用 Apache Xalan 按其 productId 对产品变体列表进行分组。这是一个输入样本：

***input_1.xml***

<?xml version="1.0" encoding="utf-8"?>
<root>
    <variant>
        <productId>1</productId>
        <price>100</price>
        <stock unit="item">10</stock>
        <attributes>
            <attribute name="color" value="red" />
        </attributes>
    </variant>
    <variant>
        <productId>1</productId>
        <price>100</price>
        <stock unit="item">8</stock>
        <attributes>
            <attribute name="color" value="blue" />
        </attributes>
    </variant>
    <variant>
        <productId>1</productId>
        <price>150</price>
        <stock unit="item">12</stock>
        <attributes>
            <attribute name="color" value="green" />
        </attributes>
    </variant>
    <variant>
        <productId>2</productId>
        <price>200</price>
        <stock unit="item">7</stock>
        <attributes>
            <attribute name="color" value="purple" />
            <attribute name="material" value="faux-leather" />
        </attributes>
    </variant>
    <variant>
        <productId>3</productId>
        <price>190</price>
        <stock unit="item">22</stock>
        <attributes>
            <attribute name="color" value="yellow" />
            <attribute name="size" value="XL" />
        </attributes>
    </variant>
    <variant>
        <productId>3</productId>
        <price>180</price>
        <stock unit="item">13</stock>
        <attributes>
            <attribute name="color" value="yellow" />
            <attribute name="size" value="L" />
        </attributes>
    </variant>
    <variant>
        <productId>3</productId>
        <price>170</price>
        <stock unit="item">5</stock>
        <attributes>
            <attribute name="color" value="yellow" />
            <attribute name="size" value="M" />
        </attributes>
    </variant>
    <variant>
        <productId>3</productId>
        <price>170</price>
        <stock unit="item">7</stock>
        <attributes>
            <attribute name="color" value="yellow" />
            <attribute name="size" value="S" />
        </attributes>
    </variant>
    <variant>
        <productId>3</productId>
        <price>180</price>
        <stock unit="item">12</stock>
        <attributes>
            <attribute name="color" value="yellow" />
            <attribute name="size" value="XS" />
        </attributes>
    </variant>
</root>

然后我在 shell 中使用以下命令：

xalan -in input_1.xml -xsl muenchian_1.xsl -out output_1.xml -indent 4

使用以下样式表转换输入：

***muenchian_1.xml***

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"   >
    <xsl:strip-space elements="*" />
    <xsl:output method="xml" indent="yes"/>
    <xsl:key name="variants-by-productId" match="/root/variant" use="productId"/>
    <xsl:template match="@*|node()" name="identity">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>
    <xsl:template match="/root/variant[productId][generate-id() =
         generate-id(key('variants-by-productId', productId)[1])]" priority="1">
        <product-listing-group>
            <productId>
                <xsl:value-of select="productId"/>
            </productId>
            <xsl:for-each select="key('variants-by-productId', productId)">
                <xsl:call-template name="identity" />
            </xsl:for-each>
        </product-listing-group>
    </xsl:template>
</xsl:stylesheet>

期望得到以下输出：

***expected_1.xml***

<?xml version="1.0" encoding="utf-8"?>
<root>
    <product>
        <productId>1</productId>
        <variant>
            <price>100</price>
            <stock unit="item">10</stock>
            <attributes>
                <attribute name="color" value="red" />
            </attributes>
        </variant>
        <variant>
            <price>100</price>
            <stock unit="item">8</stock>
            <attributes>
                <attribute name="color" value="blue" />
            </attributes>
        </variant>
        <variant>
            <price>150</price>
            <stock unit="item">12</stock>
            <attributes>
                <attribute name="color" value="green" />
            </attributes>
        </variant>
    </product>
    <product>
        <productId>2</productId>
        <variant>
            <price>200</price>
            <stock unit="item">7</stock>
            <attributes>
                <attribute name="color" value="purple" />
                <attribute name="material" value="faux-leather" />
            </attributes>
        </variant>
    </product>
    <product>
        <productId>3</productId>
        <variant>
            <price>190</price>
            <stock unit="item">22</stock>
            <attributes>
                <attribute name="color" value="yellow" />
                <attribute name="size" value="XL" />
            </attributes>
        </variant>
        <variant>
            <price>180</price>
            <stock unit="item">13</stock>
            <attributes>
                <attribute name="color" value="L" />
            </attributes>
        </variant>
        <variant>
            <price>170</price>
            <stock unit="item">5</stock>
            <attributes>
                <attribute name="color" value="M" />
            </attributes>
        </variant>
        <variant>
            <price>170</price>
            <stock unit="item">7</stock>
            <attributes>
                <attribute name="color" value="S" />
            </attributes>
        </variant>
        <variant>
            <price>180</price>
            <stock unit="item">12</stock>
            <attributes>
                <attribute name="color" value="XS" />
            </attributes>
        </variant>
    </product>
</root>

但我得到了：

***output_1.xml***

<?xml version="1.0" encoding="UTF-8"?>
<root>
    <product-listing-group>
        <productId>1</productId>
        <variant>
            <productId>1</productId>
            <price>100</price>
            <stock unit="item">10</stock>
            <attributes>
                <attribute name="color" value="red"/>
            </attributes>
        </variant>
        <variant>
            <productId>1</productId>
            <price>100</price>
            <stock unit="item">8</stock>
            <attributes>
                <attribute name="color" value="blue"/>
            </attributes>
        </variant>
        <variant>
            <productId>1</productId>
            <price>150</price>
            <stock unit="item">12</stock>
            <attributes>
                <attribute name="color" value="green"/>
            </attributes>
        </variant>
    </product-listing-group>
    <variant>
        <productId>1</productId>
        <price>100</price>
        <stock unit="item">8</stock>
        <attributes>
            <attribute name="color" value="blue"/>
        </attributes>
    </variant>
    <variant>
        <productId>1</productId>
        <price>150</price>
        <stock unit="item">12</stock>
        <attributes>
            <attribute name="color" value="green"/>
        </attributes>
    </variant>
    <product-listing-group>
        <productId>2</productId>
        <variant>
            <productId>2</productId>
            <price>200</price>
            <stock unit="item">7</stock>
            <attributes>
                <attribute name="color" value="purple"/>
                <attribute name="material" value="faux-leather"/>
            </attributes>
        </variant>
    </product-listing-group>
    <product-listing-group>
        <productId>3</productId>
        <variant>
            <productId>3</productId>
            <price>190</price>
            <stock unit="item">22</stock>
            <attributes>
                <attribute name="color" value="yellow"/>
                <attribute name="size" value="XL"/>
            </attributes>
        </variant>
        <variant>
            <productId>3</productId>
            <price>180</price>
            <stock unit="item">13</stock>
            <attributes>
                <attribute name="color" value="yellow"/>
                <attribute name="size" value="L"/>
            </attributes>
        </variant>
        <variant>
            <productId>3</productId>
            <price>170</price>
            <stock unit="item">5</stock>
            <attributes>
                <attribute name="color" value="yellow"/>
                <attribute name="size" value="M"/>
            </attributes>
        </variant>
        <variant>
            <productId>3</productId>
            <price>170</price>
            <stock unit="item">7</stock>
            <attributes>
                <attribute name="color" value="yellow"/>
                <attribute name="size" value="S"/>
            </attributes>
        </variant>
        <variant>
            <productId>3</productId>
            <price>180</price>
            <stock unit="item">12</stock>
            <attributes>
                <attribute name="color" value="yellow"/>
                <attribute name="size" value="XS"/>
            </attributes>
        </variant>
    </product-listing-group>
    <variant>
        <productId>3</productId>
        <price>180</price>
        <stock unit="item">13</stock>
        <attributes>
            <attribute name="color" value="yellow"/>
            <attribute name="size" value="L"/>
        </attributes>
    </variant>
    <variant>
        <productId>3</productId>
        <price>170</price>
        <stock unit="item">5</stock>
        <attributes>
            <attribute name="color" value="yellow"/>
            <attribute name="size" value="M"/>
        </attributes>
    </variant>
    <variant>
        <productId>3</productId>
        <price>170</price>
        <stock unit="item">7</stock>
        <attributes>
            <attribute name="color" value="yellow"/>
            <attribute name="size" value="S"/>
        </attributes>
    </variant>
    <variant>
        <productId>3</productId>
        <price>180</price>
        <stock unit="item">12</stock>
        <attributes>
            <attribute name="color" value="yellow"/>
            <attribute name="size" value="XS"/>
        </attributes>
    </variant>
</root>

正如您所看到的，当变量被正确分组时，除了各自组中的第一个变量外，所有变量都重复了两次，一次在分组内，一次在分组外。

这是为什么？我该如何解决？

【参考方案1】：

您需要阻止处理组中的第二个、第三个、第四个、.. 变体，否则默认身份转换会复制它们：

<xsl:template match="/root/variant[productId][not(generate-id() = generate-id(key('variants-by-productId', productId)[1]))]"/>

【讨论】：

你能不能也告诉我为什么身份转换不复制第一个？

好吧，对于第一个，您已经使用xsl:template match="/root/variant[productId][generate-id() = generate-id(key('variants-by-productId', productId)[1])]" 设置了模板以输出包装器product-listing-group，因此显然身份转换不会像match="@* | node()" 那样启动（其中这里node() 可以匹配）具有较低的优先级（默认情况下），因为任何match="variant" 或match="/root/variant..."。但是谓词generate-id() = generate-id(key('variants-by-productId', productId)[1])基本上是. is key('...', ...)[1]的XSLT 1方式