presentation of data rich:tree HtmlTree

Component identification parameters

Name | Value
--- | ---
component-type | org.richfaces.Tree
component-class | org.richfaces.component.html.HtmlTree
component-family | org.richfaces.Tree
renderer-type | org.richfaces.TreeRenderer
tag-class | org.richfaces.taglib.TreeTag

## Creating the Component with a Page Tag

There are two ways to set up a tree: 1) with <rich:recursiveTreeNodesAdaptor> or <rich:treeNodesAdaptor> 2) and without them. The first method allows to omit "value" and "var" attributes definition as follows:

Example:

    ...
    <rich:tree>
        <rich:recursiveTreeNodesAdaptor roots="#{fileSystemBean.sourceRoots}" var="item" nodes="#{item.nodes}" />
    </rich:tree>
    ...

The second way requires defining some attributes, as it's shown in the example:

Example:

    ...
    <rich:tree value="#{library.data}" var="item" >
        <rich:treeNode  icon="/images/tree/singer.png" >
            <h:outputText value="#{item.name}" />
        </rich:treeNode>
        ...
    </rich:tree>
    ...

## Creating the Component Dynamically Using Java

Example:

    import org.richfaces.component.html.HtmlTree;
    ...
    HtmlTree myTree = new HtmlTree();
    ...

## Details of Usage

As it has been mentioned above the <rich:tree> component allows rendering any tree-like data model.

The component interacts with data model via "TreeNode" interface (org.richfaces.model.TreeNode) that is used for tree nodes representation. The "value" attribute of the <rich:tree> component contains a nodes structure defined in a bean property. The property keeps a structure of objects that implements "TreeNode" interface.

<rich:treeNode> has a property "data" (see org.richfaces.model.TreeNode). Data contained in the property is placed in a request scope variable, which name is defined with "var" attribute for the <rich:tree> component.

You can develop and use your own pattern of the "TreeNode" interface or use a default implementation, which is defined with a default class "TreeNodeImpl" (org.richfaces.model.TreeNodeImpl).

There is a "XmlTreeDataBuilder" class (org.richfaces.component.xml.XmlTreeDataBuilder) that allows transforming XML into structures of objects containing "XmlNodeData" (org.richfaces.component.xml.XmlNodeData) instances as data, which could be represented by the <rich:tree> component.

It's possible to define a visual representation of a node data model (to define a node icon) and its behavior in correspondence with the data contained in this node (with a value of the "var" attribute). The node behavior is defined by the components nested into the <rich:treeNode> (e.g. links or buttons). For these purposes you should use "nodeFace" attribute. For each tree node a value of "nodeFace" attribute is evaluated and <rich:treeNode> with a value of "type" attribute equal to a value of "nodeFace" is used for node representation. See an example below.

Example:

    ...
    <h:form>
        <rich:tree style="width:300px" value="#{library.data}" var="item" nodeFace="#{item.type}">
            <rich:treeNode type="artist" iconLeaf="/images/tree/singer.png" icon="/images/tree/singer.png">
                <h:outputText value="#{item.name}" />
            </rich:treeNode>
            <rich:treeNode type="album" iconLeaf="/images/tree/disc.png" icon="/images/tree/disc.png">
                <h:outputText value="#{item.title}" />
            </rich:treeNode>
            <rich:treeNode type="song" iconLeaf="/images/tree/song.png" icon="/images/tree/song.png">
                <h:outputText value="#{item.title}" />
            </rich:treeNode>
        </rich:tree>
    </h:form>
    ...

This is a result:

The "nodeFace" attribute usage

In the example above, when each node of data model is processed, data contained in the "data" property of "TreeNode" interface is assigned to a request scope variable, which name is defined with "var" attribute. The value of the "nodeFace" attribute is evaluated in correspondence with the data assigned to the "var" attribute. The corresponding <rich:treeNode> component (with a value of "type" attribute equal to a value of "nodeFace" ) is used for the node representation. For example, during data model processing, an object with a name "Chris Rea" was inserted in the "var" attribute. Then the value of "nodeFace" attribute was evaluated as "artist". Thus, for the node representation the <rich:treeNode> with "type" equal to "artist" was used.

You can also assign an EL-expression as value of the "nodeFace" attribute. See an example below:

Example:

    nodeFace="#{data.name != 'param-value' ? 'artist' : 'album'}"

There are some essential points in a "nodeFace" attribute usage: you need to define notions for typeless and a default nodes.

The typeless node is the first <rich:treeNode> component (from all children nodes nested to the <rich:tree> component) with not defined "type" attribute and defined "rendered" attribute. The typeless node is used for representation when "nodeFace" attribute is null.

Default node has the following interior presentation:

Example:

    ...
    <h:outputText value="#{varAttributeName}">
    ...

"varAttributeName" is a value for "var" attribute.

Default node is used in the following cases:

- "nodeFace" attribute is defined, but its value isn't equal to any "type" attribute value from all children nodes;
- "nodeFace" attribute is defined and its value is equal to a value of some "type" attribute from all children nodes , but the value of "rendered" attribute for this node is "false".

There is also one thing that has to be remembered using "type" and "rendered" attributes: it's possible to define several <rich:treeNode> components with equal values of "type" attribute and different values of "rendered" attribute. It provides a possibility to define different representation styles for the same node types. In the example with artists and their albums (see above) it's possible to represent albums that are available for sale and albums that are not available. Please study the example below:

Example:

    ...
    <h:form>
        <rich:tree style="width:300px" value="#{library.data}" var="item" nodeFace="#{item.type}">
        ...
            <rich:treeNode type="album" iconLeaf="/images/tree/album.gif" icon="/images/tree/album.gif"
                          rendered="#{item.exist}">
                <h:outputText value="#{item.name}" />
            </rich:treeNode>
            <rich:treeNode type="album" iconLeaf="/images/tree/album_absent.gif" icon="/images/tree/album_absent.gif"
                          rendered="#{not item.exist}">
                <h:outputText value="#{item.name}" />
            </rich:treeNode>
        ...
        </rich:tree>
    </h:form>
    ...

This is a result of the code:

The "type" and the "rendered" attributes usage

In the example the <rich:treeNode> components has equal values of the "type" attribute. Depending on value of the "rendered" attribute the corresponding <rich:treeNode> component is selected for node representation. If an album is available for sale the value of the "rendered" for the first <rich:treeNode> component is "true", for the second one is "false". Thus, the first <rich:treeNode> is selected for node representation.

Tree node can be run in tree modes. Modes can be specified with "switchType" attribute for <rich:tree> component.

- Ajax (default value) - Ajax submission is used performing the functionality. Note, that for collapse/expand operations an Ajax request is sent to the server and it can cause a short delay.
- Server - regular form of submission request is used.
- Client – all operations are performed totally on the client; no interaction with a server is involved. Full page content is reloaded after every action.

The "icon" , "iconCollapsed" , "iconExpanded" , "iconLeaf" attributes set the icons' images for the component. You can also define icons using facets with the same names. If the facets are defined, the corresponding attributes are ignored and facets' content is used as icons. By default the width of a rendered facet area is 16px.

Example:

    ...
    <rich:tree value="#{library.data}" var="item">
        ...
        <f:facet name="icon">
            <h:graphicImage value="/images/tree/singer.png "/>
        </f:facet>
        <f:facet name="iconCollapsed">
            <h:graphicImage value="/images/tree/singer.png " />
        </f:facet>
        <f:facet name="iconExpanded">
            <h:graphicImage value="/images/tree/singer.png " />
        </f:facet>
        <f:facet name="iconLeaf">
            <h:graphicImage value="/images/tree/song.png " />
        </f:facet>
        ...
    </rich:tree>
    ...

The <rich: tree> component can be used together with <rich: treeNodeAdaptor> . In this case there is no need to specify the attributes "value" and "var" . Besides, visual representation shouldn't be defined right in the tree. In this case a <rich: tree> tag is applied mainly for defining common attributes such as "ajaxSubmitSelection" etc.

## Built-In Drag and Drop

The <rich: tree> component functionality provides a built-in support for Drag and Drop operations. The main usage principles are similar to RichFaces DnD wrapper components. Hence, to get additional information on the issue, read the corresponding chapters:"rich:dndParam", "rich:dragSupport", "rich:dragIndicator", "rich:dropSupport". Since treeNodescan be assigned as Drag, Drop or Drag-and-Drop elements, a tree can include the following groups of attributes.

Drag group

Attribute Name | Description
--- | ---
dragValue | Element value drag passed into processing after a Drop event
dragListener | A listener that processes a Drag event
dragIndicator | Id of a component that is used as a drag pointer during the drag operation
dragType | Defines a drag zone type that is used for definition of a dragged element, which can be accepted by a drop zone

Drop group

Attribute Name | Description
--- | ---
dropValue | Element value drop passed into processing after Drop events
dropListener | A listener that processes a Drop event.
acceptedTypes | Drag zone names are allowed to be processed with a Drop zone
typeMapping | Drag zones names mapping on the corresponding drop zone parameters

Please see an example below.

Example:

    ...
    <h:form>
        <rich:tree dragIndicator=":treeDragIndicator" dropListener="#{libraryAjaxTree.processDrop}" style="width:300px" value="#{libraryAjaxTree.data}" var="item" nodeFace="#{item.type}">
            <rich:treeNode type="artist" acceptedTypes="album" iconLeaf="/images/tree/group.png" icon="/images/tree/group.png">
                <h:outputText value="#{item.name}" />
            </rich:treeNode>
            <rich:treeNode type="album" dragType="album" acceptedTypes="song" iconLeaf="/images/tree/cd.png" icon="/images/tree/cd.png">
                <h:outputText value="#{item.title}" />
                <rich:dndParam name="label" type="drag" value="Album: #{item.title}" />
            </rich:treeNode>
            <rich:treeNode type="song" dragType="song" iconLeaf="/images/tree/music.png" icon="/images/tree/music.png">
                <h:outputText value="#{item.title}" />
                <rich:dndParam name="label" type="drag" value="Song: #{item.title}" />
            </rich:treeNode>
        </rich:tree>
    </h:form>
    ...

In the shown example a song from one album can be dragged into another because attribute "acceptedTypes" ="song" defined in the second treeNode with "type"="album". Its value is equal to the value of the "type"attribute defined in the third treeNode (see picture below). An album can be also dragged into treeNode with "type" ="artist" property.

DnD operations

## Events handling

Listeners classes that process events on the server side are defined with the help of:

- changeExpandListener processes expand/collapse event of a treeNode
- dropListener processes a Drop event
- dragListener processes a Drag event
- nodeSelectListener is called during request sending on a node selecting event (if request sending on this event is defined)

Listener methods can be defined using the following attributes or using nested tags.

Client event attributes are:

- onexpand is a script expression to invoke when a node is expanded
- oncollapse is a script expression to invoke when a node is collapsed
- ondragexit is a script expression to invoke when an element passing out from a tree zone
- ondragstart is a script expression to invoke when dragging starts
- ondragend is a script expression to invoke when dragging ends (a drop event)
- ondragenter is a script expression to invoke when a dragged element appears on a tree

They can be used to add some JavaScript effects.

Standart HTML event attributes like "onclick" , "onmousedown" , "onmouseover" etc. can be also used. Event handlers of a <rich:tree> component capture events occured on any tree part. But event handlers of treeNode capture events occured on treeNode only, except for children events.

## Look-and-Feel Customization

For skinnability implementation, the components use a style class redefinition method. Default style classes are mapped on skin parameters.

There are two ways to redefine the appearance of all <rich:tree> components at once:

- Redefine the corresponding skin parameters

- Add to your style sheets style classes used by a <rich:tree> component

## Skin Parameters Redefinition:

There is only one skin parameter for <rich:tree> . As it's a wrapper component for <rich:treeNode> components, look and feel customization is described in the corresponding section.

Skin parameters for a wrapper element

Skin parameters | CSS properties
--- | ---
overAllBackground | background-color

## Definition of Custom Style Classes

Classes names that define a component appearance

Class name | Description
--- | ---
rich-tree | Defines styles for a wrapper <div> element of a tree

In order to redefine styles for all <rich:tree> components on a page using CSS, it's enough to create classes with the same names (possible classes could be found in the table above) and define necessary properties in them. An example is placed below:

Example:

    ...
     .rich-tree{
        font-weight:bold;
    }
    ...

This is a result:

Redefinition styles with predefined classes

In the example a tree font weight was changed to bold.

Also it's possible to change styles of a particular <rich:tree> component. In this case you should create own style classes and use them in corresponding <rich:tree> styleClass attributes. An example is placed below:

Example:

    ...
    .myClass{
        font-weight:bold;
    }
    ...

The "highlightedClass" attribute for <rich:tree> is defined as it’s shown in the example below:

Example:

    ...
    <rich:tree ... styleClass="myClass"/>
    ...

This is a result:

Redefinition styles with own classes and styleClass attributes

As it's shown on the picture above, font weight of highlighted text node of a tree was changed to bold.

## Relevant Resources Links

Here you can see the example of <rich:tree> usage and sources for the given example.

How to Expand/Collapse Tree Nodes from code, see here.