Java Reference
In-Depth Information
<require extend='false' filter='(&(package=org.foo.shape)
(version>=4.0.0)(version<5.0.0))' multiple='false' name='package'
optional='false'>
Import package org.foo.shape ;version=[4.0.0,5.0.0)
</require>
</resource>
The capability elements
B
and
C
represent what the bundle provides. In this case,
B
represents the bundle itself, because the bundle can be required (for example,
Require-Bundle
), whereas
C
represents the package exported by the bundle. Bundle
dependencies are represented as requirement elements, such as the one for an
imported package
D
. Both capabilities and requirements have a name, which is actu-
ally a namespace; it's how capabilities are matched to requirements. For example,
capabilities representing exported packages and requirements representing imported
packages both have the
package
namespace.
In general, a
capability
is a set of properties specified using a
<p>
element with the
following attributes:
■
n
—The name of the property
■
v
—The value of the property
■
t
—The type of the property, which is one of the following:
◆
string
—A string value, which is the default
◆
version
—An
OSG
i version
◆
uri
—A
URI
◆
long
—A long value
◆
double
—A double value
◆
set
—A comma-separated list of values
Looking more closely at the bundle capability
B
, you see it's a fairly straightforward
mapping from the bundle identification metadata:
D
Requirement
element
Bundle-ManifestVersion: 2
Bundle-Name: Simple Paint API
Bundle-SymbolicName: org.foo.shape
Bundle-Version: 4.0
Likewise, the package capability
C
is also a simple mapping from the bundle's
Export-Package
header:
Export-Package: org.foo.shape;version="4.0"
A
requirement
is an
LDAP
query over the properties of a capability. So, to match a
requirement to a capability, first the namespace must match. If that matches, the
requirements
LDAP
query must match the properties supplied by the capabilities.
Even with the
LDAP
query, the package requirement
D
is a fairly easy mapping from
the
Import-Package
header:
Import-Package: org.foo.shape;version="[4.0,5.0)"
