magoffin.matt.ma2.support
Class AbstractMediaHandler

java.lang.Object
  magoffin.matt.ma2.support.AbstractMediaHandler

All Implemented Interfaces:

MediaHandler

Direct Known Subclasses:

BaseImageMediaHandler, BasicIconBasedMediaHandler

public abstract class AbstractMediaHandler
extends java.lang.Object
implements MediaHandler

Base class for MediaHandler implementations.

This class is a good starting point for MediaHandler implementations to extend. It provides many useful methods common to most implementations.

The handleMetadata(MediaRequest, Resource, MediaItem) method makes use of SmetaMediaMetadata to extract metadata from media resources, so is able to handle any file type supported by the application's configuration of sMeta.

The configurable properties of this class are:

domainObjectFactory

The DomainObjectFactory to use for creating new domain objects.

mediaBiz

An instance of the MediaBiz to use.

userBiz

An instance of the UserBiz for getting user locale information from.

preferredFileExtension

The file extension to use for the media files processed by this MediaHandler. In many cases there is a one-to-one mapping of MediaHandler instances to file types they support, and thus will only need to return a single file extension at all times. This property can be configured with this file extension.

mime

A MIME type to associate with this handler. Similarly to how the preferredFileExtension is configurable in this class, this MIME type property allows implementations to return a single MIME type for every file handled by each instance of this class.

smetaPropertyMap

An optional Map of JavaBean properties to apply to each SmetaMediaMetadata instance created in the getMediaMetadataInstance(MediaRequest, Resource, MediaItem) method. A Spring BeanWrapper is used on the newly created objects, so this provides a way to initialize properties on those objects after they are created.

noWatermarkSizes

A Set of MediaSize instances which should not have a watermark applied, if a user has a watermark configured. This defaults to all thumbnail sizes.

Version:

$Revision: 176 $ $Date: 2008-12-28 14:33:18 +1300 (Sun, 28 Dec 2008) $

Author:

matt.magoffin

Field Summary

protected org.apache.log4j.Logger	log A class Logger.
static java.lang.String	METADATA_PARAMETER_KEY An MediaRequest parameter key for a cached MediaMetadata object.

Constructor Summary

AbstractMediaHandler(java.lang.String mime)
Construct with MIME type.

Method Summary

protected void	applyEffects(MediaItem item, MediaRequest request, MediaResponse response) Apply the effects for a request.
protected java.util.List<Metadata>	createMetadataList(java.util.Map<java.lang.String,java.lang.String> map) Create a new List of Metadata instances from a Map.
protected void	defaultHandleRequestOriginal(MediaItem item, org.springframework.core.io.Resource itemResource, MediaResponse response) Handle the original media data, without altering.
DomainObjectFactory	getDomainObjectFactory()
MediaEffect	getEffect(java.lang.String key, java.util.Map<java.lang.String,?> effectParameters) Get a MediaEffect instance for a specific key.
java.lang.String	getFileExtension(MediaItem item, MediaRequest request) Get the file extension.
MediaBiz	getMediaBiz()
protected MediaMetadata	getMediaMetadataInstance(MediaRequest request, org.springframework.core.io.Resource mediaResource, MediaItem item) Get a MediaMetadata instance for the given resource.
java.lang.String	getMime()
java.util.Set<MediaSize>	getNoWatermarkSizes()
java.lang.String	getPreferredFileExtension()
protected java.util.List<MediaEffect>	getRequestEffects(MediaItem item, MediaRequest request) Get a list of effects to apply to a request.
java.util.Map<java.lang.String,java.lang.Object>	getSmetaPropertyMap()
UserBiz	getUserBiz()
protected MediaMetadata	handleMetadata(MediaRequest request, org.springframework.core.io.Resource mediaResource, MediaItem item) Extract metadata from a resource and replace item metadata with all extracted data.
protected boolean	needToAlter(MediaItem item, MediaRequest request) Test if the current request needs to alter the original media item in some way or not.
protected boolean	needToRotate(MediaItem item, MediaRequest request) Check if rotation needs to be performed for a given media item.
void	setDomainObjectFactory(DomainObjectFactory domainObjectFactory)
void	setMediaBiz(MediaBiz mediaBiz)
void	setMime(java.lang.String mime)
void	setNoWatermarkSizes(java.util.Set<MediaSize> noWatermarkSizes)
void	setPreferredFileExtension(java.lang.String preferredFileExtension)
void	setSmetaPropertyMap(java.util.Map<java.lang.String,java.lang.Object> smetaPropertyMap)
void	setUserBiz(UserBiz userBiz)

Methods inherited from class java.lang.Object

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

Methods inherited from interface magoffin.matt.ma2.MediaHandler

createNewMediaItem, handleMediaRequest

Field Detail

METADATA_PARAMETER_KEY

public static final java.lang.String METADATA_PARAMETER_KEY

An MediaRequest parameter key for a cached MediaMetadata object.

See Also:

Constant Field Values

log

protected final org.apache.log4j.Logger log

A class Logger.

Constructor Detail

AbstractMediaHandler

public AbstractMediaHandler(java.lang.String mime)

Construct with MIME type.

Parameters:

mime - the MIME type

Method Detail

createMetadataList

protected java.util.List<Metadata> createMetadataList(java.util.Map<java.lang.String,java.lang.String> map)

Create a new List of Metadata instances from a Map.

This will return a list of newly-constructed Metadata objects, using the keys of the map to call Metadata.setKey(String) and the corresponding map values to call Metadata.setValue(String). This can be useful for converting metadata properties returned by sMeta into Metadata objects for persisting on a MediaItem (i.e. by adding the list to MediaItem.getMetadata().

Parameters:

map - the map of properties to turn into Metadata

Returns:

the list of newly created Metadata objects

handleMetadata

protected MediaMetadata handleMetadata(MediaRequest request,
                                       org.springframework.core.io.Resource mediaResource,
                                       MediaItem item)

Extract metadata from a resource and replace item metadata with all extracted data.

This method provides a simple way to populate the Metadata list of a newly created MediaItem. It will generate the list of Metadata and then add all of them into the List returned by MediaItem.getMetadata().

This method first calls getMediaMetadataInstance(MediaRequest, Resource, MediaItem) to create a new instance of MediaMetadata and then calls MediaMetadata.setMediaResource(Resource).

If MediaMetadata.getCreationDate() returns a non-null value then a new Calendar instance will be created from it and used to set the creationDate property of the MediaItem.

If the MediaMetadata is an instance of EmbeddedImageMetadata then EmbeddedImageMetadata.getEmbeddedImage() will be called, and the width/height of the returned image will be used to set the width/height properties of the MediaItem provided.

Parameters:

request - the reqeust (may be null)

mediaResource - the media resource to extract the metadata from

item - the item to replace the extracted metadata in

Returns:

the resulting metadata instance

getMediaMetadataInstance

protected MediaMetadata getMediaMetadataInstance(MediaRequest request,
                                                 org.springframework.core.io.Resource mediaResource,
                                                 MediaItem item)

Get a MediaMetadata instance for the given resource.

This implementation returns a new SmetaMediaMetadata instance. Extending classes may want to change this behavior or set properties onto the returned instance.

If the getSmetaPropertyMap() is configured, then the created instance will have all the properties defined in that Map set onto it before being returned. This allows the instance to be easily configured. The properties are set via a Spring BeanWrapper so should follow those naming conventions.

If the request parameter is not null then the SmetaMediaMetadata instance will also be placed into the parameter Map of the MediaRequest, using the key METADATA_PARAMETER_KEY.

Parameters:

request - the reqeust (may be null)

mediaResource - the resource

item - the item

Returns:

a new MediaMetadata instance

getFileExtension

public java.lang.String getFileExtension(MediaItem item,
                                         MediaRequest request)

Get the file extension.

This method simply returns getPreferredFileExtension(). Extending class may override this for request-specific handling.

Specified by:

getFileExtension in interface MediaHandler

Parameters:

item - the media item to process

request - the request

Returns:

a file extension, without the period

getEffect

public MediaEffect getEffect(java.lang.String key,
                             java.util.Map<java.lang.String,?> effectParameters)

Description copied from interface: MediaHandler

Get a MediaEffect instance for a specific key.

Implementaions must define the keys they support, and define the parameters that go with it.

Specified by:

getEffect in interface MediaHandler

Parameters:

key - the key of the desired effect

effectParameters - a Map of parameters (optional)

Returns:

a MediaEffect instance

getRequestEffects

protected java.util.List<MediaEffect> getRequestEffects(MediaItem item,
                                                        MediaRequest request)

Get a list of effects to apply to a request.

This method provides a way to create a list of standard effects useful for every request:

1. Resizing: scaling to the size requested by MediaRequest.getSize(). If the requested width/height are not the same as those returned by MediaItem.getWidth() and MediaItem.getHeight() then this method will call MediaHandler.getEffect(String, Map) using the key MediaEffect.KEY_SCALE.
2. Rotation: if the MediaRequest.getParameters() contains the key MediaEffect.MEDIA_REQUEST_PARAM_ROTATE_DEGREES, then this method will call MediaHandler.getEffect(String, Map) using the key MediaEffect.KEY_ROTATE.

Extending classes that wish to support additional effects can override this method, adding any additional effects to the returned list as desired.

Parameters:

item - the item the effects are to be applied to

request - the current request

Returns:

list of effects (or empty list of no effects appropriate for this request)

applyEffects

protected void applyEffects(MediaItem item,
                            MediaRequest request,
                            MediaResponse response)

Apply the effects for a request.

This method provides a default way to apply effects to a media request.

This method will call getRequestEffects(MediaItem, MediaRequest) and the call MediaEffect.apply(MediaItem, MediaRequest, MediaResponse) for each effect returned. Note the MediaHandler implementation must have set up any required parameters needed by the effects prior to calling this method.

Parameters:

item - the item to apply the effects to

request - the current request

response - the current response

needToAlter

protected boolean needToAlter(MediaItem item,
                              MediaRequest request)

Test if the current request needs to alter the original media item in some way or not.

This method provides a way test if there are any alterations needed to satifsy the request, including:

1. Resize (scale): if the request is for a size different from the MediaItem.getWidth() or MediaItem.getHeight().
2. Recompress: if the request is not for MediaQuality.HIGHEST.
3. Effects: if MediaRequest.getEffects() has at least one effect in it.
4. Rotate: if needToRotate(MediaItem, MediaRequest) returns true.

If any of these are found to be true then this method will also return true.

Parameters:

item - the item being tested

request - the current request

Returns:

boolean

needToRotate

protected boolean needToRotate(MediaItem item,
                               MediaRequest request)

Check if rotation needs to be performed for a given media item.

This method will return true if any of the following are found to be true:

1. The MediaRequest.getParameters() Map contains a key MediaEffect.MEDIA_REQUEST_PARAM_ROTATE_DEGREES.
2. The MediaRequest.getEffects() contains an effect where MediaEffect.getKey() ends with MediaEffect.KEY_ROTATE.

Parameters:

item - the item

request - the request

Returns:

boolean

defaultHandleRequestOriginal

protected void defaultHandleRequestOriginal(MediaItem item,
                                            org.springframework.core.io.Resource itemResource,
                                            MediaResponse response)

Handle the original media data, without altering.

This method will call MediaResponse.setMimeType(String) with the value of getMime(). Then it will call MediaResponse.setMediaLength(long) with the value returned by the itemResource's File File.length(). It will also call MediaResponse.setModifiedDate(long) with the value returned by File.lastModified().

Finally, it will copy the file to the MediaResponse.getOutputStream().

Parameters:

item - the item to handle

itemResource - the item's Resource

response - the response

getDomainObjectFactory

public DomainObjectFactory getDomainObjectFactory()

Returns:

Returns the domainObjectFactory.

setDomainObjectFactory

public void setDomainObjectFactory(DomainObjectFactory domainObjectFactory)

Parameters:

domainObjectFactory - The domainObjectFactory to set.

getMediaBiz

public MediaBiz getMediaBiz()

Returns:

Returns the mediaBiz.

setMediaBiz

public void setMediaBiz(MediaBiz mediaBiz)

Parameters:

mediaBiz - The mediaBiz to set.

getPreferredFileExtension

public java.lang.String getPreferredFileExtension()

Returns:

Returns the preferredFileExtension.

setPreferredFileExtension

public void setPreferredFileExtension(java.lang.String preferredFileExtension)

Parameters:

preferredFileExtension - The preferredFileExtension to set.

getMime

public java.lang.String getMime()

Returns:

the mime

setMime

public void setMime(java.lang.String mime)

Parameters:

mime - the mime to set

getSmetaPropertyMap

public java.util.Map<java.lang.String,java.lang.Object> getSmetaPropertyMap()

Returns:

the smetaPropertyMap

setSmetaPropertyMap

public void setSmetaPropertyMap(java.util.Map<java.lang.String,java.lang.Object> smetaPropertyMap)

Parameters:

smetaPropertyMap - the smetaPropertyMap to set

getUserBiz

public UserBiz getUserBiz()

Returns:

the userBiz

setUserBiz

public void setUserBiz(UserBiz userBiz)

Parameters:

userBiz - the userBiz to set

getNoWatermarkSizes

public java.util.Set<MediaSize> getNoWatermarkSizes()

Returns:

the noWatermarkSizes

setNoWatermarkSizes

public void setNoWatermarkSizes(java.util.Set<MediaSize> noWatermarkSizes)

Parameters:

noWatermarkSizes - the noWatermarkSizes to set