transform only the specified elements, dropping the rest

Question

I am trying to develop an XSLT stylesheet which will transform an xml into another by keeping in view:

1. By default the stylesheet should display nothing for each element (not even the text).
2. If there is an explicit template match for an element, then copy that element, it's attributes and all its sub-elements (and their attributes).

In other words, identity transform only the elements explicitly specified.

Answer 1

Well, to do nothing for most, surely something like:

<xsl:template match="/*">
  <xsl:copy>
    <xsl:apply-templates select="*"/>
  </xsl:copy>
</xsl:template>
<xsl:template match="*">
    <xsl:apply-templates select="*"/>
</xsl:template>

Then add matches for what you do want:

<xsl:template match="Foo | Bar">
    <xsl:copy-of select="."/>
</xsl:template>

However, it seems like a very unusual requirement. Normally you simply use matches that navigate to the known content through knowledge of the xml.