org.apache.wicket.markup.html.image

Class Image

java.lang.Object

org.apache.wicket.Component

org.apache.wicket.markup.html.WebComponent

org.apache.wicket.markup.html.image.Image

All Implemented Interfaces:

Serializable, IEventSink, IEventSource, IConverterLocator, IRequestListener, IResourceListener, IHeaderContributor, IRequestableComponent, IHierarchical<Component>, IClusterable

Direct Known Subclasses:

NonCachingImage, Source

public class Image
extends WebComponent
implements IResourceListener

An Image component displays localizable image resources.

For details of how Images load, generate and manage images, see LocalizedImageResource. The first ResourceReference / ImageResource is used for the src attribute within the img tag, all following are applied to the srcset. If setXValues(String... values) is used the values are set behind the srcset elements in the order they are given to the setXValues(String... valus) method. The separated values in the sizes attribute are set with setSizes(String... sizes)

Author:

Jonathan Locke, Tobias Soloschenko

See Also:

NonCachingImage, Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Image.Cors To be used for the crossOrigin attribute

Field Summary

Fields inherited from class org.apache.wicket.Component

ENABLE, FLAG_AFTER_RENDERING, FLAG_INITIALIZED, FLAG_PREPARED_FOR_RENDER, FLAG_REMOVING_FROM_HIERARCHY, FLAG_RENDERING, FLAG_RESERVED1, FLAG_RESERVED2, FLAG_RESERVED3, FLAG_RESERVED4, FLAG_RESERVED5, FLAG_RESERVED8, PARENT_PATH, PATH_SEPARATOR, RENDER, RFLAG_CONTAINER_DEQUEING

Fields inherited from interface org.apache.wicket.IResourceListener

INTERFACE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Image(String id) This constructor can be used if you override getImageResourceReference() or getImageResource()
	Image(String id, IModel<?> model)
	Image(String id, IResource imageResource, IResource... imageResources) Constructs an image directly from an image resource.
	Image(String id, ResourceReference resourceReference, PageParameters resourceParameters, ResourceReference... resourceReferences) Constructs an image from an image resourcereference.
	Image(String id, ResourceReference resourceReference, ResourceReference... resourceReferences) Constructs an image from an image resourcereference.
	Image(String id, String string)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	addAntiCacheParameter(ComponentTag tag) Adds random noise to the url every request to prevent the browser from caching the image.
protected void	buildSizesAttribute(ComponentTag tag) builds the sizes attribute of the img tag
protected String	buildSrcAttribute(ComponentTag tag) Builds the src attribute
protected void	buildSrcSetAttribute(ComponentTag tag) Builds the srcset attribute if multiple localizedImageResources are found as varargs
boolean	canCallListenerInterface(Method method) Checks whether or not a listener method can be invoked on this component.
Image.Cors	getCrossOrigin() Gets the cross origin settings
protected IResource	getImageResource()
protected ResourceReference	getImageResourceReference()
protected boolean	getStatelessHint() Returns whether the component can be stateless.
protected IModel<?>	initModel() Called when a null model is about to be retrieved in order to allow a subclass to provide an initial model.
protected void	onComponentTag(ComponentTag tag) Processes the component tag.
void	onComponentTagBody(MarkupStream markupStream, ComponentTag openTag) Processes the body.
void	onResourceRequested() Called when a resource is requested.
void	removeSizes() Removes all sizes values.
void	removeXValues() Removes all x values from the image src set
void	setCrossOrigin(Image.Cors crossOrigin) Sets the cross origin settings ANONYMOUS: Cross-origin CORS requests for the element will not have the credentials flag set. USE_CREDENTIALS: Cross-origin CORS requests for the element will have the credentials flag set. NO_CORS: The empty string is also a valid keyword, and maps to the Anonymous state.
Component	setDefaultModel(IModel<?> model) Sets the given model.
void	setImageResource(IResource imageResource)
void	setImageResourceReference(ResourceReference resourceReference)
void	setImageResourceReference(ResourceReference resourceReference, PageParameters parameters)
void	setImageResourceReferences(PageParameters parameters, ResourceReference... resourceReferences)
void	setImageResources(IResource... imageResources)
void	setSizes(String... sizes)
void	setXValues(String... values)
protected boolean	shouldAddAntiCacheParameter() Adding an image to AjaxRequestTarget most of the times mean that the image has changes and must be re-rendered.

Methods inherited from class org.apache.wicket.markup.html.WebComponent

getWebApplication, getWebPage, getWebRequest, getWebResponse, getWebSession, onRender

Methods inherited from class org.apache.wicket.Component

add, addStateChange, afterRender, beforeRender, canCallListenerInterfaceAfterExpiry, checkComponentTag, checkComponentTagAttribute, checkHierarchyChange, clearOriginalDestination, configure, continueToOriginalDestination, createConverter, debug, detach, detachModel, detachModels, determineVisibility, error, exceptionMessage, fatal, findMarkupStream, findPage, findParent, findParentWithAssociatedMarkup, get, getAjaxRegionMarkupId, getApplication, getBehaviorById, getBehaviorId, getBehaviors, getBehaviors, getClassRelativePath, getConverter, getDefaultModel, getDefaultModelObject, getDefaultModelObjectAsString, getDefaultModelObjectAsString, getEscapeModelStrings, getFeedbackMessages, getFlag, getId, getInnermostModel, getInnermostModel, getLocale, getLocalizer, getMarkup, getMarkupAttributes, getMarkupId, getMarkupId, getMarkupIdFromMarkup, getMarkupIdImpl, getMarkupSourcingStrategy, getMetaData, getModelComparator, getOutputMarkupId, getOutputMarkupPlaceholderTag, getPage, getPageRelativePath, getParent, getPath, getRenderBodyOnly, getRequest, getRequestCycle, getRequestFlag, getResponse, getSession, getSizeInBytes, getString, getString, getString, getStyle, getVariation, hasBeenRendered, hasErrorMessage, hasFeedbackMessage, info, internalInitialize, internalOnModelChanged, internalPrepareForRender, internalRenderComponent, internalRenderHead, isActionAuthorized, isAuto, isBehaviorAccepted, isEnableAllowed, isEnabled, isEnabledInHierarchy, isIgnoreAttributeModifier, isRenderAllowed, isRendering, isStateless, isVersioned, isVisibilityAllowed, isVisible, isVisibleInHierarchy, markRendering, modelChanged, modelChanging, newMarkupSourcingStrategy, onAfterRender, onAfterRenderChildren, onBeforeRender, onConfigure, onDetach, onEvent, onInitialize, onModelChanged, onModelChanging, onReAdd, onRemove, prepareForRender, redirectToInterceptPage, remove, remove, render, renderComponentTag, rendered, renderHead, renderHead, renderPlaceholderTag, replaceComponentTagBody, replaceWith, sameInnermostModel, sameInnermostModel, send, setAuto, setDefaultModelObject, setEnabled, setEscapeModelStrings, setFlag, setIgnoreAttributeModifier, setMarkup, setMarkupId, setMarkupIdImpl, setMetaData, setOutputMarkupId, setOutputMarkupPlaceholderTag, setParent, setRenderBodyOnly, setRequestFlag, setResponsePage, setResponsePage, setResponsePage, setVersioned, setVisibilityAllowed, setVisible, success, toString, toString, urlFor, urlFor, urlFor, urlFor, urlFor, visitParents, visitParents, warn, wrap

Methods inherited from class java.lang.Object

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

Constructor Detail

Image

protected Image(String id)

This constructor can be used if you override getImageResourceReference() or getImageResource()

Parameters:

id -

Image

public Image(String id,
     ResourceReference resourceReference,
     ResourceReference... resourceReferences)

Constructs an image from an image resourcereference. That resource reference will bind its resource to the current SharedResources. If you are using non sticky session clustering and the resource reference is pointing to a Resource that isn't guaranteed to be on every server, for example a dynamic image or resources that aren't added with a IInitializer at application startup. Then if only that resource is requested from another server, without the rendering of the page, the image won't be there and will result in a broken link.

Parameters:

id - See Component

resourceReference - The shared image resource used in the src attribute

resourceReferences - The shared image resources used in the srcset attribute

Image

public Image(String id,
     ResourceReference resourceReference,
     PageParameters resourceParameters,
     ResourceReference... resourceReferences)

Constructs an image from an image resourcereference. That resource reference will bind its resource to the current SharedResources. If you are using non sticky session clustering and the resource reference is pointing to a Resource that isn't guaranteed to be on every server, for example a dynamic image or resources that aren't added with a IInitializer at application startup. Then if only that resource is requested from another server, without the rendering of the page, the image won't be there and will result in a broken link.

Parameters:

id - See Component

resourceReference - The shared image resource used in the src attribute

resourceParameters - The resource parameters

resourceReferences - The shared image resources used in the srcset attribute

Image

public Image(String id,
     IResource imageResource,
     IResource... imageResources)

Constructs an image directly from an image resource. This one doesn't have the 'non sticky session clustering' problem that the ResourceReference constructor has. But this will result in a non 'stable' url and the url will have request parameters.

Parameters:

id - See Component

imageResource - The image resource used in the src attribute

imageResources - The image resource used in the srcset attribute

Image

public Image(String id,
     IModel<?> model)

See Also:

Component.Component(String, IModel)

Image

public Image(String id,
     String string)

Parameters:

id - See Component

string - Name of image

See Also:

Component.Component(String, IModel)

Method Detail

onResourceRequested

public void onResourceRequested()

Description copied from interface: IResourceListener

Called when a resource is requested.

Specified by:

onResourceRequested in interface IResourceListener

See Also:

IResourceListener.onResourceRequested()

setImageResource

public void setImageResource(IResource imageResource)

Parameters:

imageResource - The new ImageResource to set.

setImageResources

public void setImageResources(IResource... imageResources)

Parameters:

imageResources - the new ImageResource to set.

setImageResourceReference

public void setImageResourceReference(ResourceReference resourceReference)

Parameters:

resourceReference - The shared ImageResource to set.

setImageResourceReference

public void setImageResourceReference(ResourceReference resourceReference,
                             PageParameters parameters)

Parameters:

resourceReference - The resource reference to set.

parameters - the parameters to be applied to the localized image resource

setImageResourceReferences

public void setImageResourceReferences(PageParameters parameters,
                              ResourceReference... resourceReferences)

Parameters:

parameters - Set the resource parameters for the resource.

resourceReferences - The resource references to set.

setXValues

public void setXValues(String... values)

Parameters:

values - the x values to be used in the srcset

removeXValues

public void removeXValues()

Removes all x values from the image src set

setSizes

public void setSizes(String... sizes)

Parameters:

sizes - the sizes to be used in the size

removeSizes

public void removeSizes()

Removes all sizes values. The corresponding attribute will not be rendered anymore.

setDefaultModel

public Component setDefaultModel(IModel<?> model)

Description copied from class: Component

Sets the given model.

WARNING: DO NOT OVERRIDE THIS METHOD UNLESS YOU HAVE A VERY GOOD REASON FOR IT. OVERRIDING THIS MIGHT OPEN UP SECURITY LEAKS AND BREAK BACK-BUTTON SUPPORT.

Overrides:

setDefaultModel in class Component

Parameters:

model - The model

Returns:

This

See Also:

Component.setDefaultModel(org.apache.wicket.model.IModel)

getImageResource

protected IResource getImageResource()

Returns:

Resource returned from subclass

getImageResourceReference

protected ResourceReference getImageResourceReference()

Returns:

ResourceReference returned from subclass

initModel

protected IModel<?> initModel()

Description copied from class: Component

Called when a null model is about to be retrieved in order to allow a subclass to provide an initial model.

By default this implementation looks components in the parent chain owning a IComponentInheritedModel to provide a model for this component via IComponentInheritedModel.wrapOnInheritance(Component).

For example a FormComponent has the opportunity to instantiate a model on the fly using its id and the containing Form's model, if the form holds a CompoundPropertyModel.

Overrides:

initModel in class Component

Returns:

The model

See Also:

Component.initModel()

onComponentTag

protected void onComponentTag(ComponentTag tag)

Description copied from class: Component

Processes the component tag. Overrides of this method most likely should call the super implementation.

Overrides:

onComponentTag in class Component

Parameters:

tag - Tag to modify

See Also:

Component.onComponentTag(ComponentTag)

buildSrcSetAttribute

protected void buildSrcSetAttribute(ComponentTag tag)

Builds the srcset attribute if multiple localizedImageResources are found as varargs

Parameters:

tag - the component tag

buildSrcAttribute

protected String buildSrcAttribute(ComponentTag tag)

Builds the src attribute

Parameters:

tag - the component tag

Returns:

the value of the src attribute

buildSizesAttribute

protected void buildSizesAttribute(ComponentTag tag)

builds the sizes attribute of the img tag

Parameters:

tag - the component tag

shouldAddAntiCacheParameter

protected boolean shouldAddAntiCacheParameter()

Adding an image to AjaxRequestTarget most of the times mean that the image has changes and must be re-rendered.

With this method the user may change this default behavior for some of her images.

Returns:

true to add the anti cache request parameter, false - otherwise

addAntiCacheParameter

protected void addAntiCacheParameter(ComponentTag tag)

Adds random noise to the url every request to prevent the browser from caching the image.

Parameters:

tag -

getStatelessHint

protected boolean getStatelessHint()

Description copied from class: Component

Returns whether the component can be stateless. Also the component behaviors must be stateless, otherwise the component will be treat as stateful. In order for page to be stateless (and not to be stored in session), all components (and component behaviors) must be stateless.

Overrides:

getStatelessHint in class Component

Returns:

whether the component can be stateless

See Also:

Component.getStatelessHint()

onComponentTagBody

public void onComponentTagBody(MarkupStream markupStream,
                      ComponentTag openTag)

Description copied from class: Component

Processes the body.

Overrides:

onComponentTagBody in class Component

Parameters:

markupStream - The markup stream

openTag - The open tag for the body

See Also:

Component.onComponentTagBody(MarkupStream, ComponentTag)

canCallListenerInterface

public boolean canCallListenerInterface(Method method)

Description copied from class: Component

Checks whether or not a listener method can be invoked on this component. Usually components deny these invocations if they are either invisible or disabled in hierarchy. Components can examine which listener interface is being invoked by examining the declaring class of the passed in method parameter.

WARNING: be careful when overriding this method because it may open security holes - such as allowing a user to click on a link that should be disabled.

Example usecase for overriding: Suppose you are building an component that displays images. The component generates a callback to itself using IRequestListener interface and uses this callback to stream image data. If such a component is placed inside a disabled webmarkupcontainer we still want to allow the invocation of the request listener callback method so that image data can be streamed. Such a component would override this method and return true if the listener method belongs to IRequestListener.

Overrides:

canCallListenerInterface in class Component

Parameters:

method - listener method about to be invoked on this component. Could be null - in this case it means any method.

Returns:

true iff the listener method can be invoked on this component

getCrossOrigin

public Image.Cors getCrossOrigin()

Gets the cross origin settings

Returns:

the cross origins settings

See Also:

#setCrossOrigin(Cors)}

setCrossOrigin

public void setCrossOrigin(Image.Cors crossOrigin)

Sets the cross origin settings

ANONYMOUS: Cross-origin CORS requests for the element will not have the credentials flag set.

USE_CREDENTIALS: Cross-origin CORS requests for the element will have the credentials flag set.

NO_CORS: The empty string is also a valid keyword, and maps to the Anonymous state. The attribute's invalid value default is the Anonymous state. The missing value default, used when the attribute is omitted, is the No CORS state

Parameters:

crossOrigin - the cross origins settings to set