Package org.apache.wicket.markup.html.image.resource

Class BlobImageResource

java.lang.Object

org.apache.wicket.request.resource.AbstractResource

org.apache.wicket.request.resource.DynamicImageResource

org.apache.wicket.markup.html.image.resource.BlobImageResource

All Implemented Interfaces:

Serializable, IResource, IClusterable

public abstract class BlobImageResource
extends DynamicImageResource

An ImageResource subclass for dynamic images that come from database BLOB fields. Subclasses override getBlob() to provide the image data to send back to the user. A given subclass may decide how to produce this data and whether/how to buffer it.

Author:

Eelco Hillenius

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.wicket.request.resource.AbstractResource

AbstractResource.ContentRangeType, AbstractResource.ResourceResponse, AbstractResource.WriteCallback

Nested classes/interfaces inherited from interface org.apache.wicket.request.resource.IResource

IResource.Attributes

Field Summary

Fields inherited from class org.apache.wicket.request.resource.AbstractResource

CONTENT_DISPOSITION_HEADER_NAME, CONTENT_RANGE_ENDBYTE, CONTENT_RANGE_STARTBYTE, INTERNAL_HEADERS

Constructor Summary

Constructors

Constructor	Description
BlobImageResource()	Construct.
BlobImageResource(String format)	Construct.

Method Summary

Modifier and Type	Method	Description
protected abstract Blob	getBlob(IResource.Attributes attributes)	Gets the BLOB (Binary Large OBject) that holds the raw image data.
protected byte[]	getImageData(IResource.Attributes attributes)	Get image data for our dynamic image resource.

Methods inherited from class org.apache.wicket.request.resource.DynamicImageResource

configureResponse, getFormat, newResourceResponse, setFormat, setLastModifiedTime, toImageData

Methods inherited from class org.apache.wicket.request.resource.AbstractResource

configureCache, getCachingStrategy, respond, setRequestMetaData, setRequestRangeMetaData, setResponseContentRangeHeaderFields, setResponseHeaders

Methods inherited from class java.lang.Object

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

Constructor Details

BlobImageResource

public BlobImageResource(String format)

Construct.

Parameters:

format -

BlobImageResource

public BlobImageResource()

Construct.

Method Details

getImageData

protected byte[] getImageData(IResource.Attributes attributes)

Description copied from class: DynamicImageResource

Get image data for our dynamic image resource. If the subclass regenerates the data, it should set the DynamicImageResource.setLastModifiedTime(Instant) when it does so. This ensures that image caching works correctly.

Specified by:

getImageData in class DynamicImageResource

Parameters:

attributes - the context bringing the request, response and the parameters

Returns:

The image data for this dynamic image. null means there is no image and 404 (Not found) response will be return.

getBlob

protected abstract Blob getBlob(IResource.Attributes attributes)

Gets the BLOB (Binary Large OBject) that holds the raw image data.

Parameters:

attributes - the current web attributes (request, response, parameters)

Returns:

the BLOB