/**
* Handles a call by first verifying the optional request conditions and continue the processing
* if possible. Note that in order to evaluate those conditions, {@link #getInfo()} or {@link
* #getInfo(Variant)} methods might be invoked.
*
* @return The response entity.
* @throws ResourceException
*/
protected Representation doConditionalHandle() throws ResourceException {
Representation result = null;
if (getConditions().hasSome()) {
RepresentationInfo resultInfo = null;
if (existing) {
if (isNegotiated()) {
resultInfo = doGetInfo(getPreferredVariant(getVariants(Method.GET)));
} else {
resultInfo = doGetInfo();
}
if (resultInfo == null) {
if ((getStatus() == null)
|| (getStatus().isSuccess() && !Status.SUCCESS_NO_CONTENT.equals(getStatus()))) {
setStatus(Status.CLIENT_ERROR_NOT_FOUND);
} else {
// Keep the current status as the developer might prefer
// a special status like 'method not authorized'.
}
} else {
Status status = getConditions().getStatus(getMethod(), resultInfo);
if (status != null) {
setStatus(status);
}
}
} else {
Status status = getConditions().getStatus(getMethod(), resultInfo);
if (status != null) {
setStatus(status);
}
}
if ((Method.GET.equals(getMethod()) || Method.HEAD.equals(getMethod()))
&& resultInfo instanceof Representation) {
result = (Representation) resultInfo;
} else if ((getStatus() != null) && getStatus().isSuccess()) {
// Conditions were passed successfully, continue the normal
// processing.
if (isNegotiated()) {
// Reset the list of variants, as the method differs.
getVariants().clear();
result = doNegotiatedHandle();
} else {
result = doHandle();
}
}
} else {
if (isNegotiated()) {
result = doNegotiatedHandle();
} else {
result = doHandle();
}
}
return result;
}
/**
* Handles a GET call by automatically returning the best representation available. The content
* negotiation is automatically supported based on the client's preferences available in the
* request. This feature can be turned off using the "negotiateContent" property.<br>
* <br>
* If the resource's "available" property is set to false, the method immediately returns with a
* {@link Status#CLIENT_ERROR_NOT_FOUND} status.<br>
* <br>
* The negotiated representation is obtained by calling the {@link #getPreferredVariant()}. If a
* variant is sucessfully selected, then the {@link #represent(Variant)} method is called to get
* the actual representation corresponding to the metadata in the variant.<br>
* <br>
* If no variant matching the client preferences is available, the response status is set to
* {@link Status#CLIENT_ERROR_NOT_ACCEPTABLE} and the list of available representations is
* returned in the response entity as a textual list of URIs (only if the variants have an
* identifier properly set).<br>
* <br>
* If the content negotiation is turned off and only one variant is defined in the "variants"
* property, then its representation is returned by calling the {@link #represent(Variant)}
* method. If several variants are available, then the list of available representations is
* returned in the response entity as a textual list of URIs (only if the variants have an
* identifier properly set).<br>
* <br>
* If no variant is defined in the "variants" property, the response status is set to {@link
* Status#CLIENT_ERROR_NOT_FOUND}. <br>
* If it is disabled and multiple variants are available for the target resource, then a 300
* (Multiple Choices) status will be returned with the list of variants URI if available.
* Conditional GETs are also automatically supported.
*/
@Override
public void handleGet() {
if (!isAvailable()) {
// Resource not existing or not available to the current client
getResponse().setStatus(Status.CLIENT_ERROR_NOT_FOUND);
} else {
// The variant that may need to meet the request conditions
Representation selectedRepresentation = null;
final List<Variant> variants = getVariants();
if ((variants == null) || (variants.isEmpty())) {
// Resource not found
getResponse().setStatus(Status.CLIENT_ERROR_NOT_FOUND);
getLogger()
.warning(
"A resource should normally have at least one variant added by calling getVariants().add() in the constructor. Check your resource \""
+ getRequest().getResourceRef()
+ "\".");
} else if (isNegotiateContent()) {
final Variant preferredVariant = getPreferredVariant();
if (preferredVariant == null) {
// No variant was found matching the client preferences
getResponse().setStatus(Status.CLIENT_ERROR_NOT_ACCEPTABLE);
// The list of all variants is transmitted to the client
final ReferenceList refs = new ReferenceList(variants.size());
for (final Variant variant : variants) {
if (variant.getIdentifier() != null) {
refs.add(variant.getIdentifier());
}
}
getResponse().setEntity(refs.getTextRepresentation());
} else {
// Set the variant dimensions used for content negotiation
getResponse().getDimensions().clear();
getResponse().getDimensions().add(Dimension.CHARACTER_SET);
getResponse().getDimensions().add(Dimension.ENCODING);
getResponse().getDimensions().add(Dimension.LANGUAGE);
getResponse().getDimensions().add(Dimension.MEDIA_TYPE);
// Set the negotiated representation as response entity
getResponse().setEntity(getRepresentation(preferredVariant));
}
selectedRepresentation = getResponse().getEntity();
} else {
if (variants.size() == 1) {
getResponse().setEntity(getRepresentation(variants.get(0)));
selectedRepresentation = getResponse().getEntity();
} else {
final ReferenceList variantRefs = new ReferenceList();
for (final Variant variant : variants) {
if (variant.getIdentifier() != null) {
variantRefs.add(variant.getIdentifier());
} else {
getLogger()
.warning(
"A resource with multiple variants should provide an identifier for each variant when content negotiation is turned off");
}
}
if (variantRefs.size() > 0) {
// Return the list of variants
getResponse().setStatus(Status.REDIRECTION_MULTIPLE_CHOICES);
getResponse().setEntity(variantRefs.getTextRepresentation());
} else {
getResponse().setStatus(Status.CLIENT_ERROR_NOT_FOUND);
}
}
}
if (selectedRepresentation == null) {
if ((getResponse().getStatus() == null)
|| (getResponse().getStatus().isSuccess()
&& !Status.SUCCESS_NO_CONTENT.equals(getResponse().getStatus()))) {
getResponse().setStatus(Status.CLIENT_ERROR_NOT_FOUND);
} else {
// Keep the current status as the developer might prefer a
// special status like 'method not authorized'.
}
} else {
// The given representation (even if null) must meet the request
// conditions (if any).
if (getRequest().getConditions().hasSome()) {
final Status status =
getRequest()
.getConditions()
.getStatus(getRequest().getMethod(), selectedRepresentation);
if (status != null) {
getResponse().setStatus(status);
getResponse().setEntity(null);
}
}
}
}
}