treecontroltag.java

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/*
 * Copyright 2001,2004 The Apache Software Foundation.
 * 
 * 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 netstore.framework.tag;


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

import netstore.framework.util.tree.*;


/**
 * <p>JSP custom tag that renders a tree control represented by the
 * <code>TreeControl</code> and <code>TreeControlNode</code> classes.
 * This tag has the following user-settable attributes:</p>
 * <ul>
 * <li><strong>action</strong> - Hyperlink to which expand/contract actions
 *     should be sent, with a string "<code>${node}</code> marking where
 *     the node name of the affected node should be included.</li>
 * <li><strong>images</strong> - Name of the directory containing the images
 *     for our icons, relative to the page including this tag.  If not
 *     specified, defaults to "images".</li>
 * <li><strong>scope</strong> - Attribute scope in which the <code>tree</code>
 *     attribute is to be found (page, request, session, application).  If
 *     not specified, the attribute is searched for in all scopes.</li>
 * <li><strong>style</strong> - CSS style <code>class</code> to be applied
 *     to be applied to the entire rendered output of the tree control.
 *     If not specified, no style class is applied.</li>
 * <li><strong>styleSelected</strong> - CSS style <code>class</code> to be
 *     applied to the text of any element that is currently selected.  If not
 *     specified, no additional style class is applied.</li>
 * <li><strong>styleUnselected</strong> - CSS style <code>class</code> to be
 *     applied to the text of any element that is not currently selected.
 *     If not specified, no additional style class is applied.</li>
 * <li><strong>tree</strong> - Attribute name under which the
 *     <code>TreeControl</code> bean of the tree we are rendering
 *     is stored, in the scope specified by the <code>scope</code>
 *     attribute.  This attribute is required.</li>
 * </ul>
 *
 * <strong>FIXME</strong> - Internationalize the exception messages!
 *
 * @author Craig R. McClanahan
 * @version $Revision: 1.3 $ $Date: 2004/02/27 14:59:01 $
 */

public class TreeControlTag extends TagSupport {


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


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


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


    /**
     * The hyperlink to be used for submitting requests to expand and
     * contract tree nodes.  The placeholder "<code>${name}</code>" will
     * be replaced by the <code>name</code> property of the current
     * tree node.
     */
    protected String action = null;

    public String getAction() {
        return (this.action);
    }

    public void setAction(String action) {
        this.action = action;
    }


    /**
     * The name of the directory containing the images for our icons,
     * relative to the page including this tag.
     */
    protected String images = DEFAULT_IMAGES;

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

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


    /**
     * The name of the scope in which to search for the <code>tree</code>
     * attribute.  Must be "page", "request", "session", or "application"
     * (or <code>null</code> for an ascending-visibility search).
     */
    protected String scope = null;

    public String getScope() {
        return (this.scope);
    }

    public void setScope(String scope) {
        if (!"page".equals(scope) &&
            !"request".equals(scope) &&
            !"session".equals(scope) &&
            !"application".equals(scope))
            throw new IllegalArgumentException("Invalid scope '" +
                                               scope + "'");
        this.scope = scope;
    }


    /**
     * The CSS style <code>class</code> to be applied to the entire tree.
     */
    protected String style = null;

    public String getStyle() {
        return (this.style);
    }

    public void setStyle(String style) {
        this.style = style;
    }


    /**
     * The CSS style <code>class</code> to be applied to the text
     * of selected nodes.
     */
    protected String styleSelected = null;

    public String getStyleSelected() {
        return (this.styleSelected);
    }

    public void setStyleSelected(String styleSelected) {
        this.styleSelected = styleSelected;
    }


    /**
     * The CSS style <code>class</code> to be applied to the text
     * of unselected nodes.
     */
    protected String styleUnselected = null;

    public String getStyleUnselected() {
        return (this.styleUnselected);
    }

    public void setStyleUnselected(String styleUnselected) {
        this.styleUnselected = styleUnselected;
    }


    /**
     * The name of the attribute (in the specified scope) under which our
     * <code>TreeControl</code> instance is stored.
     */
    protected String tree = null;

    public String getTree() {
        return (this.tree);
    }

    public void setTree(String tree) {
        this.tree = tree;
    }


    // --------------------------------------------------------- Public Methods


    /**
     * Render this tree control.
     *
     * @exception JspException if a processing error occurs
     */
    public int doEndTag() throws JspException {

        TreeControl treeControl = getTreeControl();
        JspWriter out = pageContext.getOut();
        try {
            out.print
                ("<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\"");
            if (style != null) {
                out.print(" class=\"");
                out.print(style);
                out.print("\"");
            }
            out.println(">");
            int level = 0;
            TreeControlNode node = treeControl.getRoot();
            render(out, node, level, treeControl.getWidth(), true);
            out.println("</table>");
        } catch (IOException e) {
            throw new JspException(e);
        }

        return (EVAL_PAGE);

    }


    /**
     * Release all state information set by this tag.
     */
    public void release() {

        this.action = null;
        this.images = DEFAULT_IMAGES;
        this.scope = null;
        this.style = null;
        this.styleSelected = null;
        this.styleUnselected = null;
        this.tree = null;

    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Return the <code>TreeControl</code> instance for the tree control that
     * we are rendering.
     *
     * @exception JspException if no TreeControl instance can be found
     */