wicket
Class AttributeModifier

java.lang.Object
  wicket.AttributeModifier

All Implemented Interfaces:

java.io.Serializable

public class AttributeModifier

extends java.lang.Object

implements java.io.Serializable

This class allows a tag attribute of a component to be modified dynamically with a value obtained from a model object. This concept can be used to programatically alter the attributes of components, overriding the values specified in the markup. The two primary uses of this class are to allow overriding of markup attributes based on business logic and to support dynamic localization. The replacement occurs as the component tag is rendered to the response.

The attribute whose value is to be modified must be given on construction of the instance of this class along with the model containing the value to replace with. Optionally a pattern can be supplied that is a regular expression that the existing value must match before the replacement can be carried out.

If an attribute is not in the markup, this modifier will add an attribute to the tag only if addAttributeIfNotPresent is true and the replacement value is not null.

Instances of this class should be added to components via the Component.add(AttributeModifier) method after the component has been constucted.

It is possible to create new subclasses of AttributeModifier by overriding the newValue(String, String) method. For example, you could create an AttributeModifier subclass which appends the replacement value like this: new AttributeModifier("myAttribute", model) { protected String newValue(final String currentValue, final String replacementValue) { return currentValue + replacementValue; } };

Author:

Chris Turner, Eelco Hillenius, Jonathan Locke, Martijn Dashorst

See Also:

Serialized Form

Constructor Summary

AttributeModifier(java.lang.String attribute, boolean addAttributeIfNotPresent, IModel replaceModel)
Create a new attribute modifier with the given attribute name and model to replace with.

AttributeModifier(java.lang.String attribute, IModel replaceModel)
Create a new attribute modifier with the given attribute name and model to replace with.

AttributeModifier(java.lang.String attribute, java.lang.String pattern, boolean addAttributeIfNotPresent, IModel replaceModel)
Create a new attribute modifier with the given attribute name and expected pattern to match plus the model to replace with.

AttributeModifier(java.lang.String attribute, java.lang.String pattern, IModel replaceModel)
Create a new attribute modifier with the given attribute name and expected pattern to match plus the model to replace with.

Method Summary

(package private) void	detachModel() Detach the model if it was a IDetachableModel Internal method.
protected IModel	getReplaceModel() Gets the replacement model.
boolean	isEnabled() Checks whether this attribute modifier is enabled or not.
protected java.lang.String	newValue(java.lang.String currentValue, java.lang.String replacementValue) Gets the value that should replace the current attribute value.
(package private) void	replaceAttibuteValue(Component component, ComponentTag tag) Checks the given component tag for an instance of the attribute to modify and if all criteria are met then replace the value of this attribute with the value of the contained model object.
void	setEnabled(boolean enabled) Sets whether this attribute modifier is enabled or not.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

AttributeModifier

public AttributeModifier(java.lang.String attribute,
                         boolean addAttributeIfNotPresent,
                         IModel replaceModel)

Create a new attribute modifier with the given attribute name and model to replace with. The additional boolean flag specifies whether to add the attribute if it is not present.

Parameters:

attribute - The attribute name to replace the value for

addAttributeIfNotPresent - Whether to add the attribute if it is not present

replaceModel - The model to replace the value with

AttributeModifier

public AttributeModifier(java.lang.String attribute,
                         IModel replaceModel)

Create a new attribute modifier with the given attribute name and model to replace with. The attribute will not be added if it is not present.

Parameters:

attribute - The attribute name to replace the value for

replaceModel - The model to replace the value with

AttributeModifier

public AttributeModifier(java.lang.String attribute,
                         java.lang.String pattern,
                         boolean addAttributeIfNotPresent,
                         IModel replaceModel)

Create a new attribute modifier with the given attribute name and expected pattern to match plus the model to replace with. A null pattern will match the attribute regardless of its value. The additional boolean flag specifies whether to add the attribute if it is not present.

Parameters:

attribute - The attribute name to replace the value for

pattern - The pattern of the current attribute value to match

addAttributeIfNotPresent - Whether to add the attribute if it is not present and the replacement value is not null

replaceModel - The model to replace the value with

AttributeModifier

public AttributeModifier(java.lang.String attribute,
                         java.lang.String pattern,
                         IModel replaceModel)

Create a new attribute modifier with the given attribute name and expected pattern to match plus the model to replace with. A null pattern will match the attribute regardless of its value. The attribute will not be added if it is not present.

Parameters:

attribute - The attribute name to replace the value for

pattern - The pattern of the current attribute value to match

replaceModel - The model to replace the value with

Method Detail

isEnabled

public boolean isEnabled()

Checks whether this attribute modifier is enabled or not.

Returns:

Whether enabled or not

setEnabled

public final void setEnabled(boolean enabled)

Sets whether this attribute modifier is enabled or not.

Parameters:

enabled - Whether enabled or not

toString

public java.lang.String toString()

See Also:

Object.toString()

newValue

protected java.lang.String newValue(java.lang.String currentValue,
                                    java.lang.String replacementValue)

Gets the value that should replace the current attribute value. This gives users the ultimate means to customize what will be used as the attribute value. For instance, you might decide to append the replacement value to the current instead of just replacing it as is Wicket's default.

Parameters:

currentValue - The current attribute value. This value might be null!

replacementValue - The replacement value. This value might be null!

Returns:

The value that should replace the current attribute value

getReplaceModel

protected final IModel getReplaceModel()

Gets the replacement model. Allows subclasses access to replace model.

Returns:

the replace model of this attribute modifier

detachModel

final void detachModel()

Detach the model if it was a IDetachableModel Internal method. shouldn't be called from the outside

replaceAttibuteValue

final void replaceAttibuteValue(Component component,
                                ComponentTag tag)

Checks the given component tag for an instance of the attribute to modify and if all criteria are met then replace the value of this attribute with the value of the contained model object.

Parameters:

component - The component

tag - The tag to replace the attribute value for