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<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Helpful Methods in the Macros Class</title><meta name="generator" content="DocBook XS methods in the <a class="ulink" href="../api/org/gjt/sp/jedit/Macros.html" target="_top allow you to converse easily with your macros. They all encapsulate calls to methods of the Java platform's <code class="classname">JOptionPane</code> class.</p><div class="itemizedlist"><ul class="ite <b class="fsfunc">message</b>(</code></td><td>Component <var class="pdparam">comp</var>, </td></tr><tr><td> </td><td>String <var class="pdparam">message</var><code>)</code>;</td></tr></table><div class="funcprototype-spac <b class="fsfunc">error</b>(</code></td><td>Component <var class="pdparam">comp</var>, </td></tr><tr><td> </td><td>String <var class="pdparam">message</var><code>)</code>;</td></tr></table><div class="funcprototype-spac <b class="fsfunc">input</b>(</code></td><td>Component <var class="pdparam">comp</var>, </td></tr><tr><td> </td><td>String <var class="pdparam">prompt</var><code>)</code>;</td></tr></table><div class="funcprototype-space <b class="fsfunc">input</b>(</code></td><td>Component <var class="pdparam">comp</var>, </td></tr><tr><td> </td><td>String <var class="pdparam">prompt</var>, </td></tr><tr><td> </td><td>String <var class="pdparam">defaultValue</var><code>)</code>;</td></tr></table><div class="funcprototype <b class="fsfunc">confirm</b>(</code></td><td>Component <var class="pdparam">comp</var>, </td></tr><tr><td> </td><td>String <var class="pdparam">prompt</var>, </td></tr><tr><td> </td><td>int <var class="pdparam">buttons</var><code> provides a concise reference to the way in which the methods may be used. The keyword <code class="function">public</code> means that the method can be used outside the <a class="ulink" href="../api/org/gjt/sp/jedit/Macros.html" target=" alternatives are <code class="function">private</code> and <code class="function">protected</code>. For purposes of BeanShell, you just have to know that BeanShell can only use public methods of other Java classes. The keyword <code class="function">static</code> we have already discussed. It means that the method does not operate on a particular object. You call a static function using the name of the class (like <a class="ulink" href="../api/org/gjt/sp/jedit/Macros.html" target="_top">Macros</a>) ra than the name of a particular object (like <code class="varname">view</code>). The third word is the type of the value returned by the method. The keyword <code class="function">void</code> is Java's way of saying the the method does not have a return value.</p><p>The <code class="function">error()</code> method works just like <code class="function">message()</code> but displays an error icon in the message box. The <code class="function">input()</code> method furnishes a text field for input, an <span class="guilabel"><strong>OK</strong></span> button and a <span class="guilabel"><strong>Cancel</strong></span> button. If <span class="guilabel"><strong>C pressed, the method returns <code class="constant">null</code>. If <span class="guilabel"><strong>OK</strong></span> is pressed, a <code class="classname">String</c containing the contents of the text field is returned. Note that there are two forms of the <code class="function">input()</code> method; the first form with two parameters displays an empty input field, the other forms lets you specify an initial, default input value.</p><p>For those without Java experience, it is impor <code class="constant">null</code> is <span class="emphasis"><em>not</em></span> the same as an empty, <span class="quote">“<span class="quote">zero-length</span>”</span> <code class="classnam Java's way of saying that there is no object associated with this variable. Whenever you seek to use a return value from <code class="function">input()</code> in your macro, you should test it to see if it is <code class="constant">null</code>. In most cases, you will want to exit gracefully from the script with a <code class="function">return</code> statement, because the presence of a null value for an input variable usually means that the user intended to cancel macro execution. BeanShell will complain if you call any methods on a <code class="constant">null</code> object.</p><p>The <code class="function">confirm()</code> method in the <a class="ulink" href=".. little more complex. The <code class="varname">buttons</code> parameter has an <code class="classname">int</code> type, and the usual way to supply a value is to use one of the predefined values taken from Java's <code class="classname">JOptionPane</code> class. You can choose among <code class="constant">JOptionPane.YES_NO_OPTION</code>, <code class="constant">JOptionPane.YES_NO_CANCEL_OPTION</code>, or <code class="constant">JOptionPane.OK_CANCEL_OPTION</code>. The return value of the method is also an <code class="classname">int</code>, and should be tested against the value of other predefined constants: <code class="constant">JOptionPane.YES_OPTION</code>, <code class="constant">JOptionPane.NO_OPTION</code>, <code class="constant">JOptionPane.OK_OPTION</code> or <code class="constant">JOptionPane.CANCEL_OPTION</code>.</p><p>We've looked at using Macr. Touse the other methods, you would write something like the following:</p><div class="informalexample"><pre class="programlisting">Macros.error(view String result = Macros.input(view, "Type something here."); String result = Macros.input(view, "When were you born?", "I don't remember, I was very young at the time"); int result = Macros.confirm(view, "Do you really want to learn" + " about BeanShell?",JOptionPane.YES_NO_OPTION); </pre></div><p>In the last three examples, placing the word <code class="classname">String</code> or <code class="classname">int</code> before the variable name <code class="varname">result</code> tells BeanShell that the variable refers to an integer or a <code class="classname">String</code> object, even before a particular value is assigned to the variable. In BeanShell, this <em class="glossterm">declaration</em> of the <em class="glossterm">type</em> of <code class="varname">result</code> is not necessary; BeanShell can figure it out when the macro runs. This can be helpful if you are not comfortable with specifying types and classes; just use your variables and let BeanShell worry about it.</p><p>Note that macros are not limited to presenting a user interface. In fact, full-blown user interfaces using the Java Swing APIs are also possible, and will be covered later on in <a class="xref" href="dialog-macro.html" title="Chapter 14. A Dialog-Based Macro">Chapt ¤ Dauer der Verarbeitung: 0.9 Sekunden (vorverarbeitet) ¤ |
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