/*****************************************************
*
* Copyright 2009 Adobe Systems Incorporated. All Rights Reserved.
*
*****************************************************
* The contents of this file are subject to the Mozilla Public License
* Version 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
* License for the specific language governing rights and limitations
* under the License.
*
*
* The Initial Developer of the Original Code is Adobe Systems Incorporated.
* Portions created by Adobe Systems Incorporated are Copyright (C) 2009 Adobe Systems
* Incorporated. All Rights Reserved.
*
*****************************************************/
package org.osmf.media
{
import flash.events.Event;
import flash.events.EventDispatcher;
import org.osmf.traits.MediaTraitBase;
import org.osmf.traits.MediaTraitType;
import org.osmf.utils.OSMFStrings;
[ExcludeClass]
/**
* Dispatched when the resolver's resolvedTrait property changed.
*
* @langversion 3.0
* @playerversion Flash 10
* @playerversion AIR 1.5
* @productversion OSMF 1.0
*/
[Event(name="change", type="flash.events.Event")]
/**
* @private
*
* Abstract base class for objects that keep a list of traits of similar type, capable
* of pointing out a so called "active" trait, that currently represents the group.
*
* @langversion 3.0
* @playerversion Flash 10
* @playerversion AIR 1.5
* @productversion OSMF 1.0
*/
internal class MediaTraitResolver extends EventDispatcher
{
/**
* Constructor
*
* @param type The MediaTraitType for traits that this resolver will be resolving.
* @throws ArgumentError If type is null.
*
* @langversion 3.0
* @playerversion Flash 10
* @playerversion AIR 1.5
* @productversion OSMF 1.0
*/
public function MediaTraitResolver(type:String)
{
if (type == null)
{
throw new ArgumentError(OSMFStrings.getString(OSMFStrings.NULL_PARAM));
}
_type = type;
}
/**
* Defines the MediaTraitType that the resolver handles.
*
* @langversion 3.0
* @playerversion Flash 10
* @playerversion AIR 1.5
* @productversion OSMF 1.0
*/
final public function get type():String
{
return _type;
}
/**
* Method for use by subclasses to set the resolved trait. Triggers
* a change event if the set value differs from the current value.
*
* @param value The trait instance to set as the resolved trait.
*
* @langversion 3.0
* @playerversion Flash 10
* @playerversion AIR 1.5
* @productversion OSMF 1.0
*/
final protected function setResolvedTrait(value:MediaTraitBase):void
{
if (value != _resolvedTrait)
{
if (_resolvedTrait)
{
_resolvedTrait = null;
dispatchEvent(new Event(Event.CHANGE));
}
_resolvedTrait = value;
dispatchEvent(new Event(Event.CHANGE));
}
}
/**
* Defines the trait instance that currently represents the group of traits as
* a whole.
*
* @langversion 3.0
* @playerversion Flash 10
* @playerversion AIR 1.5
* @productversion OSMF 1.0
*/
final public function get resolvedTrait():MediaTraitBase
{
return _resolvedTrait;
}
/**
* Adds a trait instance to the resolver. Whether the specified instance gets
* added is at the discretion of the implementing resolver.
*
* Invokes processAddTrait, that subclasses are expected to override.
*
* @param instance The instance to add.
* @throws ArgumentError If the passed trait is null, or if the trait's type
* does not match the resolver's trait type.
*
* @langversion 3.0
* @playerversion Flash 10
* @playerversion AIR 1.5
* @productversion OSMF 1.0
*/
final public function addTrait(instance:MediaTraitBase):void
{
if (instance == null)
{
throw new ArgumentError(OSMFStrings.getString(OSMFStrings.NULL_PARAM));
}
if (instance.traitType != type)
{
throw new ArgumentError(OSMFStrings.getString(OSMFStrings.INVALID_PARAM));
}
processAddTrait(instance);
}
/**
* Removes a trait instance from the resolver. Whether the specified instance gets
* removed is at the discretion of the implementing resolver.
*
* Invokes processRemoveTrait, that subclasses are expected to override.
*
* @param instance The instance to remove.
* @return The instance that was removed. Null if no matching instance was found.
* @throws ArgumentError If the passed trait is null, or if the trait's type
* does not match the resolver's trait type.
*
* @langversion 3.0
* @playerversion Flash 10
* @playerversion AIR 1.5
* @productversion OSMF 1.0
*/
final public function removeTrait(instance:MediaTraitBase):MediaTraitBase
{
if (instance == null)
{
throw new ArgumentError(OSMFStrings.getString(OSMFStrings.NULL_PARAM));
}
if (instance.traitType != type)
{
throw new ArgumentError(OSMFStrings.getString(OSMFStrings.INVALID_PARAM));
}
return processRemoveTrait(instance);
}
// Subclass stubs
//
/**
* Stub method that is invoked from addTrait. Subclasses should place their
* instance adding logic in an override to this method.
*
* @param instance The trait instance to add. On invocation of this method,
* instance has been checked for not being null, or of the wrong trait type.
*
* @langversion 3.0
* @playerversion Flash 10
* @playerversion AIR 1.5
* @productversion OSMF 1.0
*/
protected function processAddTrait(instance:MediaTraitBase):void
{
}
/**
* Stub method that is invoked from removeTrait. Subclasses should place their
* instance removing logic in an override to this method.
*
* @param instance The trait instance to add. On invocation of this method,
* instance has been checked for not being null, or of the wrong trait type.
* @return The instance that got removed, or null if no instance got removed.
*
* @langversion 3.0
* @playerversion Flash 10
* @playerversion AIR 1.5
* @productversion OSMF 1.0
*/
protected function processRemoveTrait(instance:MediaTraitBase):MediaTraitBase
{
return null;
}
private var _type:String;
private var _resolvedTrait:MediaTraitBase;
}
}
