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<TITLE>Setting a UI Default Value That Is Created When Fetched (Java Developers Almanac Example)
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<B><A HREF="../javax.swing/pkg.html#UI Default Values">UI Default Values</A></B><font color="#666666" class="xsmall-font">
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<h3>e871. Setting a UI Default Value That Is Created When Fetched</h3>
When a UI default value is fairly large and may never be used, the
value should be <font color="#0066ff"><i>lazily</i></font> created. This means that the value should
be created only when the value is fetched. The <code>UIDefaults</code> table
allows for such values.
<P> For values that are created every time they are fetched, see
<a href="../javax.swing/UiDefActive.html" class="eglink"><b>e872</b> Setting a UI Default Value That Is Created at Every Fetch</a>.
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This example declares a lazy value (a <code>JPanel</code>) that is created only
when fetched.
<pre> // Create a lazy value
Object lazyValue = new UIDefaults.LazyValue() {
// This method is called once, when the value is fetched.
// If this method can be called no more than once, it must be synchronized.
public Object createValue(UIDefaults table) {
// The returned value will be permanently stored in the UI default table
return <font color="#0066ff"><i>new JPanel()</i></font>;
}
};
// Add the lazy value to the UI defaults table
UIManager.put(<font color="#0066ff"><i>"key"</i></font>, lazyValue);
// Fetch the value; this causes the value to be created
Object value = UIManager.get(<font color="#0066ff"><i>"key"</i></font>);
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<b>Related Examples</b></font></td>
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e870. <a class="eglink" href="LookFeelDef.html?l=rel">
Getting the Default Values for a Look and Feel
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e872. <a class="eglink" href="UiDefActive.html?l=rel">
Setting a UI Default Value That Is Created at Every Fetch
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