treecontroltag.java

Java/J2EE框架Jdon-Framework系统的Sample

/**
 * Copyright 2005 Jdon.com
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

package com.jdon.strutsutil.treeview;

import java.io.IOException;
import java.net.URLEncoder;
import javax.servlet.http.*;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.TagSupport;

import com.jdon.util.Debug;

/**
 * 树形结构显示
 * 类似javascript实现功能，主要是输出Html语句，用于显示树形结构。
 *
 *
 * ViewNode :表示三层关系节点
 * TreeControl：整个树形结构节点的保存器（HashMap）
 * 本类根据以上两个基类，以level和width两个变量来绘制table表格。
 *
 *
 * <TreeView:tree
                 treeAction="updateTreeAction.do"
                nodeAction="categoryAction.do?action=edit&catId=${key}"
                target="content"
  />
 *
 *
 */
public class TreeControlTag extends TagSupport {

  private final static String module = TreeControlTag.class.getName();

  /**
   * The default directory name for icon images.
   */
  private static final String DEFAULT_IMAGES = "images";

  public static final String TREE_NAME = "tree-control";
  public static final String TREE_NAME_INIT = "tree-control-init";


  private static final String CSS_STYLE = "tree-control";
  private static final String CSS_STYLE_SELECTED = "tree-control-selected";
  private static final String CSS_STYLE_UN_SELECTED = "tree-control-unselected";

  /**
   * The names of tree state images that we need.
   */
  private static final String IMAGE_HANDLE_DOWN_LAST = "handledownlast.gif";
  private static final String IMAGE_HANDLE_DOWN_MIDDLE = "handledownmiddle.gif";
  private static final String IMAGE_HANDLE_RIGHT_LAST = "handlerightlast.gif";
  private static final String IMAGE_HANDLE_RIGHT_MIDDLE =
      "handlerightmiddle.gif";
  private static final String IMAGE_LINE_LAST = "linelastnode.gif";
  private static final String IMAGE_LINE_MIDDLE = "linemiddlenode.gif";
  private static final String IMAGE_LINE_VERTICAL = "linevertical.gif";


  // ------------------------------------------------------------- Properties

  protected String treeAction = null;
  public String getTreeAction() {
    return (this.treeAction);
  }

  public void setTreeAction(String treeAction) {
    this.treeAction = treeAction;
  }

  protected String nodeAction = null;
  public String getNodeAction() {
    return (this.nodeAction);
  }

  public void setNodeAction(String nodeAction) {
    this.nodeAction = nodeAction;
  }

  protected String target = null;

  public String getTarget() {
    return (this.target);
  }

  public void setTarget(String target) {
    this.target = target;
  }

  protected String images = DEFAULT_IMAGES;
  public String getImages() {
    return (this.images);
  }

  public void setImages(String images) {
    this.images = images;
  }

  public int doEndTag() throws JspException {

    TreeControl treeControl = (TreeControl) pageContext.findAttribute(TREE_NAME);
    JspWriter out = pageContext.getOut();

    try {
      if (treeControl == null) {
        out.print("Please login again, or refresh again");
        return (EVAL_PAGE);
      }

      out.print
          ("<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\"");
      out.print(" class=\"");
      out.print(CSS_STYLE);
      out.print("\"");
      out.println(">");
      int level = 0;
      ViewNode rootNode = treeControl.getRoot();
      render(out, rootNode, level, treeControl.getTreeWidth(), true);
      out.println("</table>");
    } catch (IOException e) {
      throw new JspException(e);
    } catch (Exception e) {
      throw new JspException("Please refresh this page!");
    }

    return (EVAL_PAGE);

  }

  //level是当前层
  protected void render(JspWriter out, ViewNode node,
                        int level, int width, boolean last) throws IOException {

    HttpServletResponse response =
        (HttpServletResponse) pageContext.getResponse();

    HttpServletRequest request =
        (HttpServletRequest) pageContext.getRequest();
    String url_Path = request.getContextPath();

//    Debug.logVerbose(" node key=" + node.getKey() + " level=" + level +
//                     " width=" + width + " last=" + last, module);

    //如果是根节点或无标签，不显示该节点
    if (node.isRoot()) {
      // Render the children of this node
      ViewNode children[] = node.findChildren();
//      Debug.logVerbose(" children count =" + children.length);
      int lastIndex = children.length - 1;
      int newLevel = level + 1;
      for (int i = 0; i < children.length; i++) {
        render(out, children[i], newLevel, width, i == lastIndex);
      }
      return;
    }

    // Render the beginning of this node
    out.println("  <tr valign=\"middle\">");

    for (int i = 0; i < level; i++) {
      int levels = level - i;
      ViewNode parent = node;
      for (int j = 1; j <= levels; j++)
        parent = parent.getParent();
      if (parent.isLast())
        out.print("    <td></td>");
      else { //显示竖线
        out.print("    <td><img src=\"");
        out.print(images);
        out.print("/");
        out.print(IMAGE_LINE_VERTICAL);
        out.print("\" alt=\"\" border=\"0\"></td>");
      }
      out.println();
    }

    displayNodePic(out, node, url_Path);
    displayNode(out, node, url_Path, level, width);

    // Render the end of this node
    out.println("  </tr>");

    // Render the children of this node
    if (node.isExpanded()) {
      ViewNode children[] = node.findChildren();
      int lastIndex = children.length - 1;
      int newLevel = level + 1;
      for (int i = 0; i < children.length; i++) {
        render(out, children[i], newLevel, width, i == lastIndex);
      }
    }

  }

  /**
   *
   *    显示节点前图形符号　　开始
   *
   *    如果该节点有子节点，符号显示IMAGE_HANDLE图形
   *     注：点按IMAGE_HANDLE，可以展开所有的子节点
   *    如果无子节点，显示IMAGE_LINE
   */
  private void displayNodePic(JspWriter out, ViewNode node, String url_Path) throws
      IOException {
    HttpServletResponse response =
        (HttpServletResponse) pageContext.getResponse();

    StringBuffer url = new StringBuffer(url_Path);
    url.append(treeAction);
    if (treeAction.indexOf("?") < 0)
      url.append("?");
    else
      url.append("&");
    url.append("key=").append(node.getKey());

    out.print("    <td>");
    if ( (nodeAction != null) && !node.isLeaf()) {
      out.print("<a href=\"");
      out.print(response.encodeURL(url.toString()));
      out.print("\">");
    }
    out.print("<img src=\"");
    out.print(images);
    out.print("/");
    if (node.isLeaf()) {
      if (node.isLast())
        out.print(IMAGE_LINE_LAST);
      else
        out.print(IMAGE_LINE_MIDDLE);
      out.print("\" alt=\"");
    } else if (node.isExpanded()) {
      if (node.isLast())
        out.print(IMAGE_HANDLE_DOWN_LAST);
      else
        out.print(IMAGE_HANDLE_DOWN_MIDDLE);
      out.print("\" alt=\"close node");
    } else {
      if (node.isLast())
        out.print(IMAGE_HANDLE_RIGHT_LAST);
      else
        out.print(IMAGE_HANDLE_RIGHT_MIDDLE);
      out.print("\" alt=\"expand node");
    }
    out.print("\" border=\"0\">");
    if ( (nodeAction != null) && !node.isLeaf())
      out.print("</a>");
    out.println("</td>");
  }

  /**
   * 显示节点本身信息，如节点名称等
   *
   * @throws IOException
   */
  private void displayNode(JspWriter out, ViewNode node, String url_Path,
                           int level, int width) throws IOException {

    HttpServletResponse response =
        (HttpServletResponse) pageContext.getResponse();

    //----------------------------------------显示节点本身信息，如节点名称等开始
    String encodedNodeKey = URLEncoder.encode(node.getKey(), "UTF-8");
    String action = replace(nodeAction, "${key}", encodedNodeKey);
    StringBuffer url = new StringBuffer(url_Path);
    url.append(action);
    if (nodeAction.indexOf("?") < 0)
      url.append("?");
    else
      url.append("&");
    url.append("key=").append(node.getKey());
    String treeNodeAction = url.toString();

    url = new StringBuffer(url_Path);
    url.append(treeAction);
    if (treeAction.indexOf("?") < 0)
      url.append("?");
    else
      url.append("&");
    url.append("select=").append(node.getKey());
    String updateNodeAction = url.toString();

    // Render the label for this node (if any)
    out.print("    <td colspan=\"");
    out.print(width - level + 1);
    out.print("\">");

    //这里省略了icon

    if (node.getLabel() != null) {
      String labelStyle = null;
      if (node.isSelected())
        labelStyle = CSS_STYLE_SELECTED;
      else if (!node.isSelected())
        labelStyle = CSS_STYLE_UN_SELECTED;
      if (treeNodeAction != null) {
        // Note the leading space so that the text has some space
        // between it and any preceding images
        out.print(" <a href=\"");
        out.print(treeNodeAction);
        out.print("\"");
        if (target != null) {
          out.print(" target=\"");
          out.print(target);
          out.print("\"");
        }
        if (labelStyle != null) {
          out.print(" class=\"");
          out.print(labelStyle);
          out.print("\"");
        }
        // to refresh the tree in the same 'self' frame
        out.print(" onclick=\"");
        out.print("self.location.href='" + updateNodeAction + "'");
        out.print("\"");
        out.print(">");
      } else if (labelStyle != null) {
        out.print("<span class=\"");
        out.print(labelStyle);
        out.print("\">");
      }
      out.print(node.getLabel());
      if (treeNodeAction != null)
        out.print("</a>");
      else if (labelStyle != null)
        out.print("</span>");
    }

    out.println("</td>");

    //----------------------------------------显示节点本身信息，如节点名称等结束

  }

  /**
   * Replace any occurrence of the specified placeholder in the specified
   * template string with the specified replacement value.
   *
   * @param template Pattern string possibly containing the placeholder
   * @param placeholder Placeholder expression to be replaced
   * @param value Replacement value for the placeholder
   */
  protected String replace(String template, String placeholder,
                           String value) {

    if (template == null)
      return (null);
    if ( (placeholder == null) || (value == null))
      return (template);
    while (true) {
      int index = template.indexOf(placeholder);
      if (index < 0)
        break;
      StringBuffer temp = new StringBuffer(template.substring(0, index));
      temp.append(value);
      temp.append(template.substring(index + placeholder.length()));
      template = temp.toString();
    }
    return (template);

  }

}