defaultabstracttree.java

Wicket一个开发Java Web应用程序框架。它使得开发web应用程序变得容易而轻松。 Wicket利用一个POJO data beans组件使得它可以与任何持久层技术相结合。

					}
					else
					{
						urls[i] = "indent-line";
					}

					parent = parent.getParent();
				}

				for (int i = level - 1; i >= 0; --i)
				{
					response.write("<span class=\"" + urls[i] + "\"></span>");
				}
			}
		};
		result.setRenderBodyOnly(true);
		return result;
	}

	/**
	 * Creates an image placed on junction link. This image actually consists of two spans with
	 * different css classes. These classes are specified according to the stylesheet to make the
	 * junction image look well together with lines connecting nodes.
	 * 
	 * @param parent
	 *            The component parent
	 * @param id
	 *            The component id
	 * @param node
	 *            The tree node
	 * @return The component that represents a junction
	 */
	protected MarkupContainer newJunctionImage(MarkupContainer parent, final String id,
		final TreeNode node)
	{
		return (MarkupContainer)new WebMarkupContainer(id)
		{
			private static final long serialVersionUID = 1L;

			/**
			 * @see org.apache.wicket.Component#onComponentTag(org.apache.wicket.markup.ComponentTag)
			 */
			protected void onComponentTag(ComponentTag tag)
			{
				super.onComponentTag(tag);

				final String cssClassInner;
				if (node.isLeaf() == false)
				{
					cssClassInner = isNodeExpanded(node) ? "minus" : "plus";
				}
				else
				{
					cssClassInner = "corner";
				}

				final String cssClassOuter = isNodeLast(node) ? "junction-last" : "junction";

				Response response = RequestCycle.get().getResponse();
				response.write("<span class=\"" + cssClassOuter + "\"><span class=\"" +
					cssClassInner + "\"></span></span>");
			}
		}.setRenderBodyOnly(true);
	}

	/**
	 * Creates the junction link for given node. Also (optionally) creates the junction image. If
	 * the node is a leaf (it has no children), the created junction link is non-functional.
	 * 
	 * @param parent
	 *            parent component of the link
	 * 
	 * @param id
	 *            wicket:id of the component
	 * 
	 * @param imageId
	 *            wicket:id of the image. this can be null, in that case image is not created. image
	 *            is supposed to be placed on the link (link is parent of image)
	 * 
	 * @param node
	 *            tree node for which the link should be created.
	 * @return The link component
	 */
	protected Component newJunctionLink(MarkupContainer parent, final String id,
		final String imageId, final TreeNode node)
	{
		final MarkupContainer junctionLink;

		if (node.isLeaf() == false)
		{
			junctionLink = newLink(parent, id, new ILinkCallback()
			{
				private static final long serialVersionUID = 1L;

				public void onClick(AjaxRequestTarget target)
				{
					if (isNodeExpanded(node))
					{
						getTreeState().collapseNode(node);
					}
					else
					{
						getTreeState().expandNode(node);
					}
					onJunctionLinkClicked(target, node);
					updateTree(target);
				}
			});
		}
		else
		{
			junctionLink = new WebMarkupContainer(id)
			{
				private static final long serialVersionUID = 1L;

				/**
				 * @see org.apache.wicket.Component#onComponentTag(org.apache.wicket.markup.ComponentTag)
				 */
				protected void onComponentTag(ComponentTag tag)
				{
					super.onComponentTag(tag);
					tag.put("onclick", "return false");
				}
			};

		}

		if (imageId != null)
		{
			junctionLink.add(newJunctionImage(junctionLink, imageId, node));
		}

		return junctionLink;
	}

	/**
	 * Creates a link of type specified by current linkType. When the links is clicked it calls the
	 * specified callback.
	 * 
	 * @param parent
	 *            The parent component
	 * @param id
	 *            The component id
	 * @param callback
	 *            The link call back
	 * @return The link component
	 */
	protected MarkupContainer newLink(MarkupContainer parent, String id,
		final ILinkCallback callback)
	{
		if (getLinkType() == LinkType.REGULAR)
		{
			return new Link(id)
			{
				private static final long serialVersionUID = 1L;

				/**
				 * @see org.apache.wicket.markup.html.link.Link#onClick()
				 */
				public void onClick()
				{
					callback.onClick(null);
				}
			};
		}
		else if (getLinkType() == LinkType.AJAX)
		{
			return new AjaxLink(id)
			{
				private static final long serialVersionUID = 1L;

				/**
				 * @see org.apache.wicket.ajax.markup.html.AjaxLink#onClick(org.apache.wicket.ajax.AjaxRequestTarget)
				 */
				public void onClick(AjaxRequestTarget target)
				{
					callback.onClick(target);
				}
			};
		}
		else
		{
			return new AjaxFallbackLink(id)
			{
				private static final long serialVersionUID = 1L;

				/**
				 * @see org.apache.wicket.ajax.markup.html.AjaxFallbackLink#onClick(org.apache.wicket.ajax.AjaxRequestTarget)
				 */
				public void onClick(AjaxRequestTarget target)
				{
					callback.onClick(target);
				}
			};
		}
	}

	/**
	 * Creates the icon for current node. By default uses image reference specified by
	 * {@link DefaultAbstractTree#getNodeIcon(TreeNode)}.
	 * 
	 * @param parent
	 *            The parent component
	 * @param id
	 *            The component id
	 * @param node
	 *            The tree node
	 * @return The web component that represents the icon of the current node
	 */
	protected Component newNodeIcon(MarkupContainer parent, String id, final TreeNode node)
	{
		return new WebMarkupContainer(id)
		{
			private static final long serialVersionUID = 1L;

			protected void onComponentTag(ComponentTag tag)
			{
				super.onComponentTag(tag);
				tag.put("style", "background-image: url('" +
					RequestCycle.get().urlFor(getNodeIcon(node)) + "')");
			}
		};

	}

	/**
	 * Creates a link that can be used to select / deselect the specified node.
	 * 
	 * @param parent
	 *            The parent component
	 * @param id
	 *            The component id
	 * @param node
	 *            The parent node
	 * @return The component that represents the link
	 */
	protected MarkupContainer newNodeLink(MarkupContainer parent, String id, final TreeNode node)
	{
		return newLink(parent, id, new ILinkCallback()
		{
			private static final long serialVersionUID = 1L;

			public void onClick(AjaxRequestTarget target)
			{
				getTreeState().selectNode(node, !getTreeState().isNodeSelected(node));
				onNodeLinkClicked(target, node);
				updateTree(target);
			}
		});
	}

	/**
	 * Callback function called after user clicked on an junction link. The node has already been
	 * expanded/collapsed (depending on previous status).
	 * 
	 * @param target
	 *            Request target - may be null on non-ajax call
	 * 
	 * @param node
	 *            Node for which this callback is relevant
	 */
	protected void onJunctionLinkClicked(AjaxRequestTarget target, TreeNode node)
	{
	}

	/**
	 * This callback method is called after user has selected / deselected the given node.
	 * 
	 * @param target
	 *            Request target - may be null on non-ajax call
	 * 
	 * @param node
	 *            Node for which this this callback is fired.
	 */
	protected void onNodeLinkClicked(AjaxRequestTarget target, TreeNode node)
	{
	}

	/**
	 * Performs the tree initialization. Adds header contribution for the stylesheet.
	 */
	private void init()
	{
		ResourceReference css = getCSS();
		if (css != null)
		{
			add(HeaderContributor.forCss(css.getScope(), css.getName()));
		}
	}

	/**
	 * Returns whether the provided node is last child of it's parent.
	 * 
	 * @param node
	 *            The node
	 * @return whether the provided node is the last child
	 */
	private boolean isNodeLast(TreeNode node)
	{
		TreeNode parent = node.getParent();
		if (parent == null)
		{
			return true;
		}
		else
		{
			return parent.getChildAt(parent.getChildCount() - 1).equals(node);
		}
	}
}