public final class ConstrainableLookupLocator extends LookupLocator implements RemoteMethodControl
LookupLocator subclass which supports constraint operations through the RemoteMethodControl interface. The constraints of a ConstrainableLookupLocator
instance control how it performs unicast discovery, and apply only to its getRegistrar() and getRegistrar(int) methods. The constraints may also be used by other utilities, such as LookupLocatorDiscovery, to determine how unicast discovery should be performed on behalf of a
given ConstrainableLookupLocator instance. Untrusted
ConstrainableLookupLocator instances can be verified using the ConstrainableLookupLocatorTrustVerifier trust verifier.DiscoveryProtocolVersion: this constraint can be used to
control which version of the unicast discovery protocol is used. UnicastSocketTimeout: this constraint can be used to control the read
timeout set on sockets over which unicast discovery is performed. ConnectionRelativeTime: this constraint can be used to control the
relative connection timeout set on sockets over which unicast discovery is performed. ConnectionAbsoluteTime: this constraint can be used to control the
absolute connection timeout set on sockets over which unicast discovery is performed.
In addition, the MulticastMaxPacketSize and MulticastTimeToLive constraint types are trivially supported, but do not
have any effect on unicast discovery operations. Constraints other than those mentioned above
are passed on to the underlying implementations of versions 1 and 2 of the discovery protocols.
An example of using constraints with ConstrainableLookupLocator is:
new ConstrainableLookupLocator("target_host", 4162, new BasicMethodConstraints(
new InvocationConstraints(
DiscoveryProtocolVersion.TWO, new UnicastSocketTimeout(120000))));
ConstrainableLookupLocator instance would (when used) perform unicast
discovery to the host target_host on port 4162 using discovery protocol version 2,
with a socket read timeout of 120000 milliseconds unless one was explicitly specified using the
getRegistrar(int) method.host, port| Constructor and Description |
|---|
ConstrainableLookupLocator(String host,
int port,
MethodConstraints constraints)
Constructs a new
ConstrainableLookupLocator instance which can be used to
perform unicast discovery to the given host and port with the provided constraints applied. |
ConstrainableLookupLocator(String url,
MethodConstraints constraints)
Constructs a new
ConstrainableLookupLocator instance which can be used to
perform unicast discovery to the host and port named by the given URL with the provided
constraints applied. |
| Modifier and Type | Method and Description |
|---|---|
MethodConstraints |
getConstraints()
Returns the client constraints placed on this proxy.
|
ServiceRegistrar |
getRegistrar()
Performs unicast discovery as specified by
LookupLocator.getRegistrar() with the
following differences. |
ServiceRegistrar |
getRegistrar(int timeout)
Performs unicast discovery as specified by
LookupLocator.getRegistrar(int),
additionally applying the supplied discovery constraints. |
RemoteMethodControl |
setConstraints(MethodConstraints constraints)
Returns a new copy of this proxy with the client constraints set to the specified
constraints.
|
String |
toString()
Returns a string representation of this object.
|
equals, getHost, getPort, hashCodepublic ConstrainableLookupLocator(String url, MethodConstraints constraints) throws MalformedURLException
ConstrainableLookupLocator instance which can be used to
perform unicast discovery to the host and port named by the given URL with the provided
constraints applied. This constructor invokes its superclass LookupLocator(String) constructor. Any exceptions thrown by the superclass
constructor are rethrown. The url must be a valid URL of scheme
"jini" as described in LookupLocator(String). A null
constraints value is interpreted as mapping both getRegistrar methods to
empty constraints.
url - the URL to useconstraints - the constraints to apply to unicast discovery, or nullMalformedURLException - if url cannot be parsedNullPointerException - if url is nullpublic ConstrainableLookupLocator(String host, int port, MethodConstraints constraints)
ConstrainableLookupLocator instance which can be used to
perform unicast discovery to the given host and port with the provided constraints applied.
This constructor invokes its superclass LookupLocator(String, int)
constructor. Any exceptions thrown by the superclass constructor are rethrown.
A null constraints value is interpreted as mapping both
getRegistrar methods to empty constraints. The host and
port must satisfy the requirements of the LookupLocator(String,
int) constructor.
host - the name of the host to contactport - the number of the port to connect toconstraints - the constraints to apply to unicast discovery, or nullNullPointerException - if host is nullIllegalArgumentException - if the port and host do not meet the requirements of
LookupLocator(String, int).public ServiceRegistrar getRegistrar() throws IOException, ClassNotFoundException
LookupLocator.getRegistrar() with the
following differences. getRegistrar(int) method. net.jini.discovery.timeout system property is ignored. ConstrainableLookupLocator implements this method to use the values of the
host and port field in determining the host and port to connect
to.getRegistrar in class LookupLocatorUnsupportedConstraintException - if the discovery-related constraints
contain conflicts, or otherwise cannot be
processedIOException - an error occurred during discoveryClassNotFoundException - if a class required to unmarshal the ServiceRegistrar
proxy cannot be foundpublic ServiceRegistrar getRegistrar(int timeout) throws IOException, ClassNotFoundException
LookupLocator.getRegistrar(int),
additionally applying the supplied discovery constraints. The timeout is
considered a requirement with respect to other constraints specified for this instance.getRegistrar in class LookupLocatortimeout - the maximum time to wait for a response, in milliseconds. A value of
0 specifies an infinite timeout.UnsupportedConstraintException - if the discovery-related constraints
contain conflicts, or otherwise cannot be
processedIOException - an error occurred during discoveryClassNotFoundException - if a class required to unmarshal the ServiceRegistrar
proxy cannot be foundpublic String toString()
toString in class LookupLocatorpublic RemoteMethodControl setConstraints(MethodConstraints constraints)
RemoteMethodControlgetConstraints method of
the copy returns the identical constraints instance. The original proxy is not modified. A
null value is interpreted as mapping all methods to empty constraints (one that
has no requirements and no preferences). For any given remote call, the specific client
requirements and preferences to be satisfied are given by the return value of invoking the
getConstraints method of the specified MethodConstraints instance with a Method object representing the
remote method. Client constraints placed on a proxy are included in the serialized state
of the proxy. This allows third-party services to be transparent to the client's needs. For
example, if remote object s1 obtains a proxy for remote object s2,
and passes that proxy to remote object s3, expecting s3 to invoke a
remote method on s2, then s1 can control that call by placing its
constraints directly on the proxy before passing it to s3. If s3
does not wish to be transparent in this way, then it should explicitly replace the client
constraints on received proxies with whatever constraints are appropriate to implement its
own policy.
setConstraints in interface RemoteMethodControlconstraints - client constraints, or nullRemoteMethodControl.getConstraints()public MethodConstraints getConstraints()
RemoteMethodControlnull, which is interpreted as mapping all methods to empty constraints (one that
has no requirements and no preferences).getConstraints in interface RemoteMethodControlnullRemoteMethodControl.setConstraints(net.jini.core.constraint.MethodConstraints)Copyright © GigaSpaces.