---
server/lib/deltacloud/backend_capability.rb | 21 ++++++++++++++++++++
.../errors/backend_capability_failure.html.haml | 11 ++++++++++
.../errors/backend_capability_failure.xml.haml | 4 +++
3 files changed, 36 insertions(+), 0 deletions(-)
create mode 100644 server/lib/deltacloud/backend_capability.rb
create mode 100644 server/views/errors/backend_capability_failure.html.haml
create mode 100644 server/views/errors/backend_capability_failure.xml.haml
diff --git a/server/lib/deltacloud/backend_capability.rb
b/server/lib/deltacloud/backend_capability.rb
new file mode 100644
index 0000000..bec8714
--- /dev/null
+++ b/server/lib/deltacloud/backend_capability.rb
@@ -0,0 +1,21 @@
+module Deltacloud::BackendCapability
+
+ class Failure < StandardError
+ attr_reader :capability
+ def initialize(capability, msg='')
+ super(msg)
+ @capability = capability
+ end
+ end
+
+ attr_reader :capability
+ def with_capability(capability)
+ @capability = capability
+ end
+
+ def check_capability(backend)
+ if capability and !backend.respond_to?(capability)
+ raise Failure.new(capability, "#{capability} capability not supported by
backend #{backend.class.name}")
+ end
+ end
+end
diff --git a/server/views/errors/backend_capability_failure.html.haml
b/server/views/errors/backend_capability_failure.html.haml
new file mode 100644
index 0000000..dc830d8
--- /dev/null
+++ b/server/views/errors/backend_capability_failure.html.haml
@@ -0,0 +1,11 @@
+%h1 Backend Capability Failure
+
+%p= @error.message
+
+%dl
+ %di
+ %dt Request URL
+ %dd= request.env['REQUEST_URI']
+ %di
+ %dt Capability
+ %dd= @error.capability
diff --git a/server/views/errors/backend_capability_failure.xml.haml
b/server/views/errors/backend_capability_failure.xml.haml
new file mode 100644
index 0000000..83892fb
--- /dev/null
+++ b/server/views/errors/backend_capability_failure.xml.haml
@@ -0,0 +1,4 @@
+%error{:url => "#{request.env['REQUEST_URI']}", :status =>
"#{response.status}"}
+ %capability #[email protected]}
+ %message #[email protected]}
+
--
1.7.2.3
