3.4.1. Number Formatting

string format-number(number, string, string?)

The first parameter is the number to format, the second is a format string, and the third (optional) is the name of an <xsl:decimal-format> element. We will cover only the first two parameters in this book. Interestingly enough, the behavior of the format-number( ) function is defined by the JDK 1.1.x version of the java.text.DecimalFormat class. For complete information on the syntax of the second argument, refer to the JavaDocs for JDK 1.1.x.

Table 3-2. Formatting currencies using $#,##0.00

The XSLT code to utilize this function may look something like this:

<xsl:value-of select="format-number(amt,'$#,##0.00')"/>

<!-- outputs 0% -->
<xsl:value-of select="format-number(0,'0%')"/>

<!-- outputs 10% -->
<xsl:value-of select="format-number(0.1,'0%')"/>

<!-- outputs 100% -->
<xsl:value-of select="format-number(1,'0%')"/>

As before, the first parameter to the format-number( ) function is the actual number to be formatted, and the second parameter is the pattern. The 0 in the pattern indicates that at least one digit should always be displayed. The % character also has the side effect of multiplying the value by 100 so it is displayed as a percentage. Consequently, 0.15 is displayed as 15%, and 1 is displayed as 100%.

This stylesheet first loops over the list of <format> elements:

<xsl:for-each select="numberFormatting/formatSamples/format">

Within the loop, all of the <number> elements are selected. This means that every format is applied to every number:

<xsl:apply-templates select="/numberFormatting/numberSamples/number">

3.4.2. Text Formatting

Let's suppose that a stylesheet defines the following variables:

<xsl:variable name="firstName" select="'Eric'"/>
<xsl:variable name="lastName" select="'Burke'"/>
<xsl:variable name="middleName" select="'Matthew'"/>
<xsl:variable name="fullName" 
    select="concat($firstName, ' ', $middleName, ' ', $lastName)"/>

In the first three variables, apostrophes are used to indicate that the values are strings. Without the apostrophes, the XSLT processor would treat these as XPath expressions and attempt to select nodes from the XML input data. The third variable, fullName, demonstrates how the concat( ) function is used to concatenate two or more strings together. The function simply takes a comma-separated list of strings as arguments and returns the concatenated results. In this case, the value for fullName is "Eric Matthew Burke."

Table 3-3. String function examples

All string comparisons, such as starts-with() and contains( ), are case-sensitive. There is no concept of case-insensitive comparison in XSLT. One potential workaround is to convert both strings to upper- or lowercase, and then perform the comparison. Converting a string to upper- or lowercase is not directly supported by a function in the current implementation of XSLT, but the translate( ) function can be used to perform the task. The following XSLT snippet converts a string from lower- to uppercase:

translate($text,
    'abcdefghijklmnopqrstuvwxyz',
    'ABCDEFGHIJKLMNOPQRSTUVWXYZ')

In the substring-before( ) and substring-after( ) functions, the second argument contains a delimiter string. This delimiter does not have to be a single character, and an empty string is returned if the delimiter is not found. These functions could be used to parse formatted data such as dates:

<date>06/25/1999</date>

The XSLT used to extract the month, day, and year looks like this:

<xsl:variable name="dateStr" select="//date"/>
<xsl:variable name="dayYear" select="substring-after($dateStr, '/')"/>
Month: <xsl:value-of select="substring-before($dateStr, '/')"/> <br/>
Day: <xsl:value-of select="substring-before($dayYear, '/')"/> <br/>
Year: <xsl:value-of select="substring-after($dayYear, '/')"/>

In the first line of code, the dateStr variable is initialized to contain the full date. The next line then creates the dayYear variable, which contains everything after the first / character -- at this point, dateStr=06/25/1999 and dayYear=25/1999. In Java, this is slightly easier because you simply create an instance of the StringTokenizer class and iterate through the tokens or use the lastIndexOf( ) method of java.lang.String to locate the second /. With XSLT, the options are somewhat more limited. The remaining lines continue chopping up the variables into substrings, again delimiting on the / character. The output is as follows:

Month: 06
Day: 25
Year: 1999