View source for Riena/UI filters

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[[Riena Project]] | [[Riena Getting started|Getting Started]] | UI Filters}}

==Introduction==
With UI filters, restrictions can be added to certain UI elements of a Riena application. For example you could add a validator to a text field or hide a sub module in the navigation.

UI Filters contain a collection of rules. When a filter is added, its rules are applied for the corresponding UI elements. A UI element can be a menu item, a node of the navigation or a ridget.

The UI Filters can be composed by adding any kind of rule. The UI filters themselves are added to any node of the navigation. The rules of a filter are only exploited for the node with this filter and all the child nodes.

At any time can filters be added to and removed from the navigation model. The changes are immediately visible in the GUI. So the UI filter can be used in a very flexible way and dynamically.

==UI Filter==
A UI filter itself only consists of a collection of rules and an identifier.
<source lang="java">
public interface IUIFilter {
	Collection<? extends IUIFilterRule> getFilterRules();
	String getFilterID();
}
</source>
UI filters can be added to any navigation node. They also can be removed. All nodes of the navigation (INavigationNode) are implemented the following interface:
<source lang="java">
public interface IUIFilterable {

	void addFilter(IUIFilter filter);

	void removeFilter(IUIFilter filter);

	void removeFilter(String filterID);

	void removeAllFilters();

	Collection<? extends IUIFilter> getFilters();

}
</source>
The implementation updates the GUI after adding or removing an UI filter.

== Rules ==
The way the UI elements will be manipulated is defined by the rules of the UI Filters. Therefore two scenarios exist.

=== Scenario 1: A UI Filter is added ===
The rule checks for every UI element if it is responsible for this element (<tt>matches</tt>).<br>
If this is the case, the rule is applied.

=== Scenario 2: A UI Filter is removed ===
Also, the rule checks for every UI element if it is responsible for this element (<tt>matches</tt>).<br>
If this is the case, the changes which are caused by this rule are removed.
<source lang="java">
public interface IUIFilterRule {

	boolean matches(Object... args);

	void apply(Object object);

	void remove(Object object);

}
</source>
The rules can be divided into several categories.
# What are the changes of the rules? Is a Marker added (<tt>IUIFilterRuleMarker</tt>) or a validator (<tt>IUIFilterRuleValidator</tt>)?
# Is the rule responsible for a navigation node or a ridget?

=== Rules for navigation nodes ===
For navigation nodes only two different rules for adding markers exists. One rule adds a <tt>DisabeldMarker</tt> (viz. the node is disabled) the other one adds a <tt>HiddenMarker</tt> (viz. the node is not visible).

The constructor of both rules (<tt>UIFilterRuleNavigationDisabledMarker</tt> and <tt>UIFilterRuleNavigationHiddenMarker)</tt> takes a pattern that is used to identify the navigation nodes. This simple pattern may contain '*' for 0 and many characters and '?' for exactly one character.

====Matches====
A rule is applied if the ID of the navigation node matches the pattern of the rule. Not only is the ID of one navigation node used for the match, also the IDs of the parent nodes. All these IDs together are called longID or completeID. Example:

Tree structure of a navigation model:<br>
<pre>
RienaApplication                 (ID=application)
    NavigationSubApplication     (ID=subApp1)
        ModuleGroup              (ID=uiprocessGroup)
            UIProcess            (ID=uiprocess)
                Demo1            (ID=demo01)
</pre>
The complete ID of the sub module “Demo1” is:<br>
<tt>/application/subApp1/uiprocessGroup/uiProcess/demo01</tt><br>
The single IDs of the nodes are separated by a slash.<br>
Because the rules can have pattern with wildcards, the following patterns matches:
* <tt>/application/subApp?/uiprocessGroup/uiProcess/demo??</tt>
* <tt>*demo01</tt>
* <tt>*/subApp1/uiprocessGroup/uiProcess/demo0*</tt>

====DisabledMarker====
The rule <tt>UIFilterRuleNavigationDisabledMarker</tt> adds a <tt>DisabledMarker</tt> to the navigation node, if the pattern of the rule matches the ID of the node (<tt>longID</tt>). The node is still visible but it cannot be selected.

====HiddenMarker====
The rule <tt>UIFilterRuleNavigationHiddenMarker</tt> adds a <tt>HiddenMarker</tt> to the navigation node, if the pattern of the rule matches the ID of the node (<tt>longID</tt>). The node is not displayed.

===Rules for Ridgets===
For ridgets two different kinds of rules exist. There are rules for adding markers and rules for adding validators.

Like creating rules for navigation nodes the constructor takes a pattern (<tt>ridgetIdPattern</tt>), that‘s used to identify the ridgets. The method <tt>matches</tt> decides, if the rule is applied.

====Matches====
Also the rules for ridgets are only applied, if the pattern of the rule matches the id of the ridget.<br>
And also like the rules for the navigation nodes the method <tt>matches</tt> compares the pattern with the complete ID of the ridget. The complete ID is composed of the IDs of the navigations nodes and the ID of the ridget.
A ridget with the ID “lastname” is part of the sub module “Demo1”. The complete ID:<br>
<tt>/application/subApp1/uiprocessGroup/uiProcess/demo01/lastname</tt>

====Marker Rules====
The following four rules add a marker, if the pattern of the rule matches the ID of the ridget:

; <tt>UIFilterRuleRidgetDisabledMarker</tt>
: This rule adds a <tt>DisabledMarker</tt>. The ridget is visible, but no value is displayed.
; <tt>UIFilterRuleRidgetHiddenMarker</tt>
: This rule adds a <tt>HiddenMarker</tt>. The ridget is not displayed.
; <tt>UIFilterRuleRidgetMandatoryMarker</tt>
: This rule adds a <tt>MandatoryMarker</tt>. The ridget is marked as long not value is entered.
; <tt>UIFilterRuleRidgetOutputMarker</tt>
: This rule adds a <tt>OutputMarker</tt>. The ridget is visible and also the value is displayed, but the value cannot be edited.

====Validator Rules====
Only one rule exists for validators. Validators (<tt>IValidator</tt>) can be added to a ridget and validate the value. If the value is invalid, an error marker is displayed. To construct this rule (<tt>UIFilterRuleRidgetValidator</tt>) the pattern for the ID, the validator and the time of validation are necessary.

The validator must implement the interface <tt>IValidator</tt>. Riena provides a set of validators: e.g. <tt>MinLength</tt>, <tt>MaxLength</tt>, <tt>ValidEmailAddress</tt>.

For adding a validator to a ridget it is necessary to specify at what points in time the values shall be validated:

; <tt>ValidationTime.ON_UI_CONTROL_EDIT</tt>
: The value is validated after every change. 
; <tt>ValidationTime.ON_UPDATE_TO_MODEL</tt>
: The value is validated before writing the value into the model.

===Rules for Menu and Tool Bar===
Menus, menu items and tool items are also ridgets of Riena. But for these, other rules are used.

====Matches====
The method <tt>matches</tt> decides whether a rule is applied. This method compares the ID of the ridget with the pattern of the rule. Unlike the other ridgets, only the ''simple'' ID of the ridget is compared.

====DisabledMarker====
The rule <tt>UIFilterRuleMenuItemDisabledMarker</tt> adds a <tt>DisabledMarker</tt> to a menu, menu item or a tool item. The menu or item is visible but is cannot be selected.

====HiddenMarker====
The rule <tt>UIFilterRuleMenuItemHiddenMarker</tt> adds a <tt>HiddenMarker</tt> to a menu, menu item or a tool item. The menu or item is invisible.

==Extension==
UI filters cannot only be composed programmatically; they can be also composed by extensions of eclipse RCP.<br>
Riena provides the extension point <tt>org.eclipse.riena.filter.uifilter</tt>.
; filter
: At top level only <tt>filter</tt> elements can be added. This element has only on Attribute: <tt>filterID.</tt>
; nodeID
: This element defines to with navigation node this UI filter will be added. It is possible to add a filter to different nodes, so the <tt>filter</tt> element can has more than one <tt>nodeID</tt> element.
; ruleMarkerNavigation
:This element creates a rule which adds a marker to a navigation node. The atrribute <tt>nodeID</tt> identifies the navigationn node and marker the type of the marker: <tt>hidden</tt> or  <tt>disabled</tt>.
; ruleMarkerRidget
: This element creates a rule which adds a marker to a ridget. The attribute <tt>ridgetId</tt> identifies the ridget and <tt>marker</tt> the type of the marker: <tt>hidden</tt>, <tt>output</tt>, <tt>mandatory</tt> or <tt>disabled</tt>
; ruleValidatorRidget
: This element creates a rule which adds a validator to a ridget. The attribute <tt>ridgetID</tt> identifies the ridget, <tt>validator</tt> defines the class of the validator and <tt>validationTime</tt> the point in time of validation (<tt>onUIControlEdit</tt> or <tt>onUpdateToModel</tt>).
: Some validators need some arguments to validate a value correctly. So these arguments can be added behind the class name of the validator. A colon separates class name and arguments. The arguments are separated by comma. A simple example is the <tt>MaxLength</tt> validator. You would set the maximum length like this: <tt>org.eclipse.riena.ui.ridgets.validation.MaxLength:12</tt>. The order of the arguments is according the parameter of the constructor.
; ruleMarkerMenuItem
: This element creates a rule which adds a marker to a menu, menu item or tool item. The attribute <tt>itemID</tt> identifies the item and <tt>marker</tt> the type of the marker: <tt>hidden</tt> or <tt>disabled</tt>.

[[Category:Riena]]