RELEASE_2_1_13/src/blocks/xsp/samples/java/interpolation.xsp

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<!-- SVN $Id$ -->

<xsp:page
  language="java"
  xmlns:xsp-interpolation="http://apache.org/xsp/interpolation/1.0"
  xmlns:xsp="http://apache.org/xsp">

  <xsp:logicsheet location="logicsheets/interpolation.xsl"/>

  <page>
    <title>Attribute and Text Interpolation</title>
    <content>
      <p>
        {#Constants.COMPLETE_NAME} allows to use
        <tt>{##expr}</tt><!-- Note ## to escape interpolation. -->
        to replace the value of the Java expression <tt>expr</tt>
        within attribute values and text nodes.
      </p>

      <p>
        For expression interpolation in text nodes the difference is to
        the usual xsp:expr syntax is minor.
        For dynamic attribute values, however, interpolation
        keeps it much more concise and readable.
      </p>
      <pre>
        <![CDATA[
        <xsp:logic>
          String world = "world";
          String color = "red";
        </xsp:logic>
        ]]>
      </pre>

      <xsp:logic>
        String world = "world";
        String color = "red";
      </xsp:logic>

      <p>
        Just compare this:
      </p>
      <!-- Use attributes to disable interpolation in nested content. -->
      <pre xsp:attr-interpolation="false" xsp:text-interpolation="false"><![CDATA[
        <center style="color:{#color}">Hello simple {#world}!</center>]]>
      </pre>
      <center style="color:{#color}">Hello simple {#world}!</center>

      <p>
        to that:
      </p>
      <pre><![CDATA[
        <center><xsp:attribute name="style">color:<xsp:expr>color</xsp:expr></xsp:attribute>Hello complex <xsp:expr>world</xsp:expr>!</center>]]>
      </pre>
      <center><xsp:attribute name="style">color:<xsp:expr>color</xsp:expr></xsp:attribute>Hello complex <xsp:expr>world</xsp:expr>!</center>

      <p>
        Interpolation can also be used in logicsheets:
      </p>
      <xsp-interpolation:greeting/>

      <p>
        The XSP expression parser understands nested braces,
        single and double quoted strings, and backslash-escaped
        quotes and apostrophes.
      </p>
      <table border="1">
        <tr>
          <th>Expression</th>
          <th>Result</th>
          <th>Expected</th>
        </tr>
        <tr>
          <td xsp:text-interpolation="false">
            {#new String[]{}.length}
          </td>
          <td>
            {#new String[]{}.length}
          </td>
          <td>
            0
          </td>
        </tr>
        <tr>
          <td xsp:text-interpolation="false">
            {#new String[]{"}"}.length}
          </td>
          <td>
            {#new String[]{"}"}.length}
          </td>
          <td>
            1
          </td>
        </tr>
        <tr>
          <td xsp:text-interpolation="false">
            {#"'\"}".indexOf('}')}
          </td>
          <td>
            {#"'\"}".indexOf('}')}
          </td>
          <td>
            2
          </td>
        </tr>
      </table>
    </content>
  </page>

</xsp:page>