hmm... this really is a bit harder than it ought to be.
below is a url encoding strategy and a sub-classable auto-mounting resource
that makes this a lot easier. you can modify to suit your needs.
the use case looks like:
// This dynamically rendered resource will auto-mount itself using the
path
and resource name given
private static final MountedDynamicImageResource redbox = new
MountedDynamicImageResource(
"/images/redbox", "redbox", 100, 100) {
private static final long serialVersionUID =
1021758684732149991L;
@Override
protected boolean render(Graphics2D graphics) {
graphics.setColor(Color.RED);
graphics.fillRect(0, 0, getWidth(), getHeight());
return true;
}
};
MyPage() {
add(redbox.getImage());
}
the code for MountedDynamicImageResource looks like:
import java.awt.Graphics2D;
import java.util.HashMap;
import java.util.Map;
import org.apache.wicket.ResourceReference;
import org.apache.wicket.markup.html.image.Image;
import
org.apache.wicket.markup.html.image.resource.RenderedDynamicImageResource;
import org.apache.wicket.protocol.http.WebApplication;
public abstract class MountedDynamicImageResource extends
RenderedDynamicImageResource {
private static final long serialVersionUID = -9117628603222075688L;
private static final Map<Class<? extends MountedDynamicImageResource>,
Boolean> mounted = new HashMap<Class<? extends MountedDynamicImageResource>,
Boolean>();
private final String name;
public MountedDynamicImageResource(final String path, final String name,
int width, int height) {
this(path, name, width, height, "png");
}
public MountedDynamicImageResource(final String path, final String name,
int width, int height, String format) {
super(width, height, format);
this.name = name;
synchronized (mounted) {
if (mounted.get(getClass()) == null) {
mounted.put(getClass(), Boolean.TRUE);
WebApplication.get().getSharedResources().add(getClass(), name,
getLocale(), null, this);
WebApplication.get().mount(
new
MountedResourceRequestTargetUrlCodingStrategy(path
+ "." + format,
getClass(), name));
}
}
}
public Image getImage() {
return new Image(name, new ResourceReference(getClass(), name));
}
/**
* {...@inheritdoc}
*/
@Override
protected abstract boolean render(Graphics2D graphics);
}
and the url coding strategy:
import org.apache.wicket.IRequestTarget;
import org.apache.wicket.request.RequestParameters;
import
org.apache.wicket.request.target.coding.AbstractRequestTargetUrlCodingStrategy;
import
org.apache.wicket.request.target.resource.ISharedResourceRequestTarget;
import
org.apache.wicket.request.target.resource.SharedResourceRequestTarget;
public class MountedResourceRequestTargetUrlCodingStrategy extends
AbstractRequestTargetUrlCodingStrategy {
private String keyPrefix;
public MountedResourceRequestTargetUrlCodingStrategy(String mountPath,
Class<?> scope) {
this(mountPath, scope, mountPath.substring(1));
}
public MountedResourceRequestTargetUrlCodingStrategy(String mountPath,
Class<?> scope, String namePrefix) {
super(mountPath);
this.keyPrefix = scope.getName() + "/" + namePrefix;
}
public IRequestTarget decode(RequestParameters requestParameters) {
String name = requestParameters.getPath().substring(
getMountPath().length());
requestParameters.setResourceKey(keyPrefix + name);
return new SharedResourceRequestTarget(requestParameters);
}
public CharSequence encode(IRequestTarget requestTarget) {
String key = ((ISharedResourceRequestTarget) requestTarget)
.getResourceKey();
return getMountPath() + key.substring(keyPrefix.length());
}
public boolean matches(IRequestTarget requestTarget) {
if (!(requestTarget instanceof ISharedResourceRequestTarget))
return false;
String key = ((ISharedResourceRequestTarget) requestTarget)
.getResourceKey();
return key.startsWith(keyPrefix);
}
}
merry xmas!
smallufo wrote:
>
> Hi
>
> I hope I can use wicket to serve image data.
> I know I can extend org.apache.wicket.markup.html.image.Image and provide
> a
> DynamicImageResource
> but the generated image link is
> http://localhost/app/?wicket:interface=:0:customImage::IResourceListener::
> The image data is stored in the session and not bookmarkable, which is not
> what I want.
>
>
> I then created an ImagePage extends WebPage and override onBeforeRender()
> ,
> and coding below :
> HttpServletResponse response = ((WebResponse)
> getWebRequestCycle().getResponse()).getHttpServletResponse();
> try
> {
> response.setContentType("image/png");
>
> OutputStream responseOutputStream = response.getOutputStream();
>
> responseOutputStream.write(myImageBytes);
> responseOutputStream.flush();
> responseOutputStream.close();
> }
> catch (IOException e)
> {
> e.printStackTrace();
> }
>
> It works !!! And I can bookmark the image.
>
> But there are warning output :
>
> 2008-12-26 02:20:42,919 ERROR wicket.RequestCycle -
> org.apache.wicket.Component has not been properly rendered. Something in
> the
> hierarchy of foo.bar.ImagePage has not called super.onBeforeRender() in
> the
> override of onBeforeRender() method
> java.lang.IllegalStateException: org.apache.wicket.Component has not been
> properly rendered. Something in the hierarchy of foo.bar.ImagePage has not
> called super.onBeforeRender() in the override of onBeforeRender() method
> at
> org.apache.wicket.Component.internalBeforeRender(Component.java:1006)
> at org.apache.wicket.Component.beforeRender(Component.java:1034)
> at
> org.apache.wicket.Component.prepareForRender(Component.java:2160)
>
> Is this the "standard" way of outputing binary data ?
> If not , what is the better way (wicket 1.3.5) ?
>
> thanks.
>
>
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