cvs commit: logging-log4j/src/java/org/apache/log4j/chainsaw/vfs VFSUtils.java

[ps...@apache.org]

psmith      2004/05/18 23:11:37

  Added:       src/java/org/apache/log4j/chainsaw/vfs VFSUtils.java
  Log:
  added utils class with a useful method.
  
  Hopefully more added here over time...
  
  Revision  Changes    Path
  1.1                  logging-log4j/src/java/org/apache/log4j/chainsaw/vfs/VFSUtils.java
  
  Index: VFSUtils.java
  ===================================================================
  package org.apache.log4j.chainsaw.vfs;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.Iterator;
  import java.util.List;
  import javax.swing.JTree;
  import javax.swing.SwingUtilities;
  import javax.swing.tree.DefaultMutableTreeNode;
  import javax.swing.tree.DefaultTreeModel;
  import javax.swing.tree.TreePath;
  import org.apache.commons.vfs.FileObject;
  import org.apache.log4j.helpers.LogLog;
  /**
   * @author psmith
   *  
   */
  class VFSUtils {
  	/**
  	 * Given a tree node, first determine if the user object is a VFSNode, and
  	 * if not, ignores the request and returns immediately. Otherwise a new,
  	 * low-priority thread is started to go look for any potential children of
  	 * the fileObject. As each child is located, an new child TreeNode is added
  	 * to the passed in node, and done within the Swing's EventDispatchThread.
  	 * 
  	 * Child TreeNodes' that are added to this node will have a VFSNode as it's
  	 * UserObject.
  	 * 
  	 * @param node
  	 */
  	static void lookForChildren(final JTree tree,
  			final DefaultMutableTreeNode node) {
  		Object object = node.getUserObject();
  		if (!(object instanceof VFSNode)) {
  			return;
  		}
  		final VFSNode vfsNode = (VFSNode) object;
  		Thread thread = new Thread(new BackgroundChildFileObjectPopulator(tree,
  				node, vfsNode));
  		thread.setPriority(Thread.MIN_PRIORITY);
  		thread.start();
  	}
  	/**
  	 * A background task that scans a vfsNode for Children, and creates Child
  	 * nodes for them dynamically.
  	 * 
  	 * @author psmith
  	 *  
  	 */
  	private static final class BackgroundChildFileObjectPopulator
  			implements
  				Runnable {
  		private final VFSNode vfsNode;
  		private final DefaultMutableTreeNode node;
  		private final JTree tree;
  		/**
  		 * @param node
  		 * @param vfsNode
  		 */
  		public BackgroundChildFileObjectPopulator(JTree tree,
  				DefaultMutableTreeNode node, VFSNode vfsNode) {
  			this.tree = tree;
  			this.node = node;
  			this.vfsNode = vfsNode;
  		}
  		/*
  		 * (non-Javadoc)
  		 * 
  		 * @see java.lang.Runnable#run()
  		 */
  		public void run() {
  			LogLog.debug("Looking for children of node " + vfsNode.getName());
  			// first, lets add a tempopary node that says "Pending..." in it
  			// while we work out what's going on.
  			final DefaultMutableTreeNode pendingNode = new DefaultMutableTreeNode(
  					"Pending...");
  			SwingUtilities.invokeLater(new Runnable() {
  				public void run() {
  					node.add(pendingNode);
  					tree.makeVisible(new TreePath(pendingNode.getPath()));
  				}
  			});
  			try {
  				List children = new ArrayList(Arrays.asList(this.vfsNode
  						.getFileObject().getChildren()));
  				Collections.sort(children, FILE_OBJECT_COMPARATOR);
  				LogLog.debug("Found " + children.size() + " children");
  				for (Iterator iter = children.iterator(); iter.hasNext();) {
  					FileObject child = (FileObject) iter.next();
  					// we only add non-leaf nodes, as the leaf nodes get
  					// displayed in the table
  					if (child.getType().hasChildren()) {
  						final DefaultMutableTreeNode childNode = new DefaultMutableTreeNode(
  								new VFSNode(child.getName().getBaseName(),
  										child));
  						SwingUtilities.invokeLater(new Runnable() {
  							public void run() {
  								node.add(childNode);
  							}
  						});
  					}
  				}
  			} catch (Exception e) {
  				// TODO feedback to the user about the error...
  				LogLog.error("Failed to populate Children", e);
  			} finally {
  				SwingUtilities.invokeLater(new Runnable() {
  					public void run() {
  						node.remove(pendingNode);
  						((DefaultTreeModel) tree.getModel()).reload(node);
  					}
  				});
  			}
  		}
  	}
  	private VFSUtils() {
  	}
      /**
       * Compares FileObject instances by their baseName, case SENSITIVE.
       */
  	static final Comparator FILE_OBJECT_COMPARATOR = new Comparator() {
  		public int compare(Object o1, Object o2) {
  			FileObject fo1 = (FileObject) o1;
  			FileObject fo2 = (FileObject) o2;
  			return fo1.getName().getBaseName().compareTo(
  					fo2.getName().getBaseName());
  		}
  	};
  }
  
  

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