Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Interface UIDefaults.LazyValue - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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Java^TM 2 Platform
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javax.swing
Interface UIDefaults.LazyValue

Enclosing class:: UIDefaults

public static interface UIDefaults.LazyValue

This class enables one to store an entry in the defaults table that isn't constructed until the first time it's looked up with one of the getXXX(key) methods. Lazy values are useful for defaults that are expensive to construct or are seldom retrieved. The first time a LazyValue is retrieved its "real value" is computed by calling LazyValue.createValue() and the real value is used to replace the LazyValue in the UIDefaults table. Subsequent lookups for the same key return the real value. Here's an example of a LazyValue that constructs a Border:

  Object borderLazyValue = new UIDefaults.LazyValue() {
      public Object createValue(UIDefaults table) {
          return new BorderFactory.createLoweredBevelBorder();
      }
  };

  uiDefaultsTable.put("MyBorder", borderLazyValue);

See Also:: UIDefaults.get(java.lang.Object)

Method Summary

Object createValue(UIDefaults table)
Creates the actual value retrieved from the UIDefaults table.

Method Detail

createValue

public Object createValue(UIDefaults table)

Creates the actual value retrieved from the UIDefaults table. When an object that implements this interface is retrieved from the table, this method is used to create the real value, which is then stored in the table and returned to the calling method.

Parameters:: table - a UIDefaults table
Returns:: the created Object