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This document covers the following topics:

• Example

• Editing the Text of the Tree Node

• Embedding Controls into TREENODE3

• Loading Large Trees - Step by Step

• Drag-and-Drop Inside a TREENODE3 Tree

• Dynamic Setting of Tree Icons

• Properties

Example

The following image shows an example for a tree management:

The grid contains three columns: the first column shows the tree node, the other two columns display some text information.

The XML layout definition is:

<rowarea name="Tree">
    <rowtablearea2 griddataprop="treeGridInfo" rowcount="8" width="500" withborder="false">
        <tr>
            <label name="Tree Node" width="200" asheadline="true">
            </label>
            <label name="Toggle Count" width="100" asheadline="true"
                   labelstyle="text-align:right">
            </label>
            <label name="Select Count" width="100" asheadline="true"
                   labelstyle="text-align:right">
            </label>
        </tr>
        <repeat>
            <tr>
                <treenode3 width="200" withplusminus="true"
                           imageopened="images/fileopened.gif"
                           imageclosed="images/fileclosed.gif"
                           imageendnode="images/fileendnode.gif">
                </treenode3>
                <textout valueprop="toggleCount" width="100" align="right">
                </textout>
                <textout valueprop="selectCount" width="100" align="right">
                </textout>
            </tr>
        </repeat>
    </rowtablearea2>
</rowarea>

You see that the TREENODE3 control is placed inside the control grid just as a normal control. There are certain properties available which influence the rendering: in the example, the name of the tree node images is statically overwritten. The flag withplusminus is set to true - consequently, small "+"/"-" icons are placed in front of the node.

The corresponding adapter code is:

// This class is a generated one.

import com.softwareag.cis.server.Adapter;
import com.softwareag.cis.server.util.NODEInfo;
import com.softwareag.cis.server.util.TREECollection;

public class tree_01Adapter
    extends Adapter
{
    // class >TreeGridInfoItem<
    public class Item extends NODEInfo
    {
        int m_toggleCount = 0;
        int m_selectCount = 0;

        public Item(String text)
        {
            super(text);
        }
        public void reactOnToggle() { m_toggleCount++; }
        public void reactOnSelect() { m_selectCount++; }
        public int getToggleCount() { return m_toggleCount; }
        public int getSelectCount() { return m_selectCount; }
    }

    // property >treeGridInfo<
    TREECollection m_treeGridInfo = new TREECollection();
    public TREECollection getTreeGridInfo() { return m_treeGridInfo; }

    /** initialisation - called when creating this instance*/
    public void init()
    {
        m_treeGridInfo = new TREECollection();
        Item item = new Item("Top");
        m_treeGridInfo.addTopNode(item,false);
        m_treeGridInfo.addSubNode(new Item("Sub 1"),item,true,false);
        Item subItem = new Item("Sub 2");
        m_treeGridInfo.addSubNode(subItem,item,false,false);
        Item subItem21 = new Item("Sub 2-1");
        m_treeGridInfo.addSubNode(subItem21,subItem,false,false);
        m_treeGridInfo.addSubNode(new Item("Sub 2-1-1"),subItem21,true,false);
        m_treeGridInfo.addSubNode(new Item("Sub 2-1-2"),subItem21,true,false);
        Item subItem22 = new Item("Sub 2-2");
        m_treeGridInfo.addSubNode(subItem22,subItem,false,false);
        m_treeGridInfo.addSubNode(new Item("Sub 2-2-1"),subItem22,true,false);
        m_treeGridInfo.addSubNode(new Item("Sub 3"),item,true,false);
        // open top node
        m_treeGridInfo.toggleNode(item);
    }
}

The grid collection is an instance of the class TREECollection from the package com.softwareag.cis.server.util. (Remember that the class GRIDCollection is used for normal grids.) The TREECollection has all functions that are required for:

• server-side scrolling,

• selecting tree nodes,

• opening and closing tree nodes.

The items of the tree collection are derived from a predefined class NODEInfo from the package com.softwareag.cis.server.util. By overwriting the methods reactOnToggle() and reactOnSelect(), you can react on user interaction. Each tree node is represented by one single instance of this item class.

The tree is built inside the init() method of the adapter. For filling the tree, the following methods of the TREECollection class are used:

• addTopNode()

• addSubNode()

See the JavaDoc documentation for more information on these methods and other methods for manipulating the tree.

The tree can be filled "all at once" - as shown in this example - or loaded step by step on the server side. For example, the tree can be extended in the reactOnToggle() method when a node is being opened.

Editing the Text of the Tree Node

You may already have seen the property withtextinput which you may set to "true". If doing so, then the user can double-click on a tree node and edit the node's text:

By pressing TAB or ENTER, the input is taken over into the tree node and is by default transferred to the adapter with the next request (e.g. when a button is chosen on the screen). Users can also use the ESC key - in this case, the tree node is set back to its former value. The server-side adapter can pick the text by the normal getText() method which is available in the tree node and is implemented on NODEInfo level.

If you want your server program to be explicitly notified by the text change, then override the setText() method inside your tree node implementation:

...
...
...
public class TreeItem extends NODEInfo
{
    ...
    ...
    ...
    public void setText(String value)
    {
        super.setText(value);
        // do your own implementation here
        outputMessage(MT_SUCCESS,"Node text changed: " + value);
    }

    ...
    ...
}
...
...
...

You can also explicitly define the point of time when the text change in the user interface is transferred to the server. As with normal input controls (FIELD, CHECKBOX, etc.), the text change is by default registered in the browser, but does not trigger an immediate transfer to the server-side adapter. By using the property flush, you can control this: setting this property to "server" will immediately synchronize the client with the adapter; setting it to "screen" will immediately synchronize inside the browser.

There is still one issue: inside the tree node item, there is the method setDisableTextInput(boolean). Calling this method will switch off the editing behavior for this tree node. Consequently, you can explicitly define tree nodes that allow to edit text and others that do not allow to do so. In case the user double-clicks onto a node that is explicitly set to be not editable, the text will be displayed in disabled format so that the user receives visual feedback that this operation is not supported for this node.

Embedding Controls into TREENODE3

It is possible to add further controls into the tree node. The typical cases are:

• a check box,

• an icon,

• a toggle control.

The toggle control offers the possibility to manipulate a boolean value - it is similar to a check box, but allows to explicitly define a "true-image" and a "false-image". When using the toggle control inside the tree node, there is one useful feature: the toggle control allows to be defined in such a way that it show three different images:

• "true-image"

• "false-image"

• "partial-image"

In trees, you typically have selections in which you want to select by toggle control one item and all of its subitems. The same goes for deselecting. But you also want to be able to express that inside one node, there are some selected subitems, but not all subitems are selected. The toggle control exactly matches these requirements. For more information, see the description of the TOGGLE control.

Loading Large Trees - Step by Step

In the example at the beginning of this TREENODE3 section, the whole TREECollection inside the adapter was filled in one step. The following example shows how to dynamically load elements into a tree that gets larger and larger due to the user's navigation in the tree.

Every time the user opens a folder, the folders "Sub 0" to "Sub 4" and the end nodes "Node 0" to "Node 4" are input into the tree hierarchy:

// This class is a generated one.

import com.softwareag.cis.server.Adapter;
import com.softwareag.cis.server.util.NODEInfo;
import com.softwareag.cis.server.util.TREECollection;

public class tree_03Adapter
    extends Adapter
{
    // class >TreeItem<
    public class TreeItem extends NODEInfo
    {
        boolean m_subNodesAvailable = false;
        public TreeItem(String text)
        {
            super(text);
        }
        public void reactOnSelect() {}
        public void reactOnToggle()
        {
            if (m_subNodesAvailable == false)
            {
                m_subNodesAvailable = true;
                addSubNodesFor(this);
            }
        }
    // property >tree<
    TREECollection m_tree = new TREECollection();
    public TREECollection getTree() { return m_tree; }

    public void init()
    {
        TreeItem top;
        for (int i=0; i<10; i++)
        {
            top = new TreeItem("Top " + i);
            m_tree.addTopNode(top,false);
        }
    }

    private void addSubNodesFor(TreeItem top)
    {
        TreeItem sub;
        for (int i=0; i<5; i++)
        {
            sub = new TreeItem("Sub " + i);
            sub.setDisableTextInput(true);
            m_tree.addSubNode(sub,top,false,false);
            sub.setOpened(TREECollection.ST_CLOSED);
        }
        for (int i=0; i<5; i++)
        {
            sub = new TreeItem("Node " + i);
            m_tree.addSubNode(sub,top,true,false);
        }
    }
}

Inside the tree node class (TreeItem), a boolean member m_subNodesAvailable indicates whether subnodes for this instance have already been loaded. In the method reactOnToggle(), new nodes are added by calling the addSubNodesFor(...) method - depending on the m_subNodesAvailable value.

If you are "very eager" or if you have for some good reason to be very strict in memory-house-keeping, then you could also remove all subnodes of a node when the node is closed.

Drag-and-Drop Inside a TREENODE3 Tree

Implementing drag-and-drop inside your tree is easy - you just have to do two things:

• Set the enabledrag property to "true" inside the TREENODE3 definitiion.

• Add a method reactOnContextMenuRequestDragTarget() into your node class and implement your reaction.

The tree node inside your page will automatically offer the following behavior: when selecting one or more nodes, you can click on the node's text, drag the nodes, and drop them onto another node's text.

Sorry for the name reactOnContextMenuRequestDragTarget() - it assumes that you ought to open a context menu, but you can do any other reaction as well. Of course, it is a nice feature to offer a context menu when the user drops items onto another item - showing the user what functions can be executed with the dropped items.

The following simple demo shows an example in which the node on which other nodes are dropped outputs the text of the dropped nodes:

...
...
...
// class >TreeItem< representing node object
public class TreeItem extends NODEInfo
{
    ...
    ...
    ...
    public void reactOnContextMenuRequestDragTarget()
    {
        // iterate through selected tree nodes and concatenate text
        NODEInfo[] selItems = m_tree.findSelectedItems();
        StringBuffer sb = new StringBuffer();
        for (int i=0; i<selItems.length; i++)
        {
            if (i != 0) sb.append(", ");
            sb.append(selItems[i].getText());
        }
        outputMessage(MT_SUCCESS,"Drop result: " + sb.toString());
    }
    ...
    ...
    ...
}
...
...
...

In the method reactOnContextMenuRequestDragTarget, the selected items are identified by using the tree collection's method findSelectedItems().

Note:
With the TREENODE3 property singleselect, you can change the tree from its default "single select mode" into "multi select mode".

Dynamic Setting of Tree Icons

There are three ways to define icons for a tree node:

• No definition at all. The nodes will be rendered with the default icons.

• Fixed definition of icons. Using the TREENODE3 properties imageopened, imageclosed and imageendnode, you can define the icons to be used.

• Dynamic definition of icons. Each node can be assigned an own icon. The icon is defined by a property of the server-side node object. The name of the property is defined inside the TREENODE3 property imageprop.

Have a look at the following example:

Each of the subnodes has its own icon, depending on its category. (An individual icon can also be used for folder nodes.)

The XML layout definition is:

<page model="com.softwareag.cis.demoapps.TreeDynamicIconsAdapter">
    <titlebar name="Tree with dynamic Icons">
    </titlebar>
    <pagebody>
        <rowarea name="Tree Demo">
            <rowtablearea2 griddataprop="lines" rowcount="10" width="100%" withborder="false">
                <repeat>
                    <tr>
                        <treenode3 width="100%" imageprop="imageName">
                        </treenode3>
                    </tr>
                </repeat>
            </rowtablearea2>
        </rowarea>
    </pagebody>
    <statusbar withdistance="false">
    </statusbar>
</page>

In the layout definition, you see that the TREENODE3 property imageprop points to the property imageName.

The adapter code is:

package com.softwareag.cis.demoapps;

// This class is a generated one.

import java.util.*;
import com.softwareag.cis.server.*;
import com.softwareag.cis.server.util.*;
import com.softwareag.cis.util.*;

public class TreeDynamicIconsAdapter
    extends Adapter
{
    public class LinesItem extends NODEInfo
    {
        public LinesItem(String text, String imageName)
        {
            super(text);
            m_imageName = imageName;
        }

        String m_imageName;
        public String getImageName() { return m_imageName; }
        public void setImageName(String value) { m_imageName = value; }

        public void reactOnSelect()
        {
        }

        public void reactOnToggle()
        {
        }
    }

    // property >lines<
    TREECollection m_lines = new TREECollection();
    public TREECollection getLines() { return m_lines; }

    public void init()
    {
        LinesItem top = new LinesItem("Printers",null);
        m_lines.addTopNode(top,false);
        m_lines.addSubNode(new LinesItem("LPT1 - Printer","images/print.gif"),top,true,true);
        m_lines.addSubNode(new LinesItem("COM - Printer","images/print.gif"),top,true,true);
        top = new LinesItem("Disks",null);
        m_lines.addTopNode(top,false);
        m_lines.addSubNode(new LinesItem("A: drive","images/save.gif"),top,true,true);
        m_lines.addSubNode(new LinesItem("B: drive","images/save.gif"),top,true,true);
        top = new LinesItem("Pencils",null);
        m_lines.addTopNode(top,false);
        m_lines.addSubNode(new LinesItem("My pencil","images/editdisabled.gif"),top,true,true);
    }

}

The imageName property is implemented on tree node level (i.e. as property inside the inner class LinesItem). In the init method, the property is defined to be "null" for the top nodes and to hold a value for the leaf nodes.

Again: you could also define an individual icon for the top nodes - in the same way you do it for the leaf nodes. The example above shows that the different ways of assigning icons build on one another: if the dynamic icon is not passed (as done with the top nodes), then these icons are selected that are defined with imageopened/imageclosed/imageendnode properties. If these are not defined (as in the example), the default icon is used.

Properties

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