treestringcomparator.java

java swing 开发代码

// TreeStringComparator.java
// This class compares the contents of the userObject as strings.
// It's case-insensitive.
//
package	jswing.ch17;

 
import java.util.*;
import javax.swing.tree.DefaultMutableTreeNode;

public class TreeStringComparator implements Comparator {
  public int compare(Object o1, Object o2) {
    if (!(o1 instanceof DefaultMutableTreeNode && 
          o2 instanceof DefaultMutableTreeNode)) {
      throw new IllegalArgumentException("Can only compare DefaultMutableTreeNode objects");
    }
    String s1 = ((DefaultMutableTreeNode)o1).getUserObject().toString();
    String s2 = ((DefaultMutableTreeNode)o2).getUserObject().toString();
    return s1.compareToIgnoreCase(s2);
  }
}