Break the XSLT for-each loop when first match is found

I am having trouble to display the first matching value, like

<test>
    <p>30</p>
    <p>30{1{{23{45<p>
    <p>23{34</p>
    <p>30{1{98</p>
</test>
<test2>
    <p1>text</p1>
</test2>

So i want to loop through the <test></test> and find the value of <p> node whose string length is greater than 2 and that contains 30. I want 开发者_如何学JAVAonly the first value. so i tired the following code

<xsl:variable name="var_test">
    <xsl:for-each select="*/*/test()>
        <xsl:if string-length(p/text())>2 and contains(p/text(),'30'))
    <xsl:value-of select="xpath">
</xsl:variable>

the problem is the var_test is being null always.

if i try directly with out any variable

<xsl:for-each select="*/*/test()>
    <xsl:if string-length(p/text())>2 and contains(p/text(),'30'))
<xsl:value-of select="xpath">

I am getting the following output

<p>30{1{23{4530{1{98</p>

but the desired output is

<p>0{1{23{45</p>

so how can i achieve this?

Instead of the for-each, use

<xsl:copy-of select="(*/*/test/p[string-length() > 2 and
                                 contains(.,'30'))] )[1]" />

The [1] selects only the first matching <p>. (Updated: I changed the XPath above in response to @markusk's comment.)

The above will output that <p> element as well as its text content, as shown in your "desired output". If you actually want only the value of the <p>, that is, its text content, use <xsl:value-of> instead of <xsl:copy-of>.

Addendum:

The idea of breaking out of a loop does not apply to XSLT, because it is not a procedural language. In a <xsl:for-each> loop, the "first" instantiation (speaking in terms of document order, or sorted order) of the loop is not necessarily evaluated at a time chronologically before the "last" instantiation. They may be evaluated in any order, or in parallel, because they do not depend on each other. So trying to "break out of the loop", which is intended to cause "subsequent" instantiations of the loop not to be evaluated, cannot work: if it did, the outcome of later instantiations would be dependent on earlier instantiations, and parallel evaluation would be ruled out.