uws.service.wait

Interface BlockingPolicy

All Known Implementing Classes:

LimitedBlockingPolicy, UserLimitedBlockingPolicy

public interface BlockingPolicy

Implementations of this interface define the policy to apply when a blocking of a request is asked by a UWS client.

Since:

4.3

Version:

4.3 (11/2017)

Author:

Grégory Mantelet (ARI)

Method Summary

Modifier and Type	Method and Description
long	block(java.lang.Thread thread, long userDuration, UWSJob job, JobOwner user, javax.servlet.http.HttpServletRequest request) Notify this BlockingPolicy that the given thread is going to be blocked for the specified duration.
void	unblocked(java.lang.Thread unblockedThread, UWSJob job, JobOwner user, javax.servlet.http.HttpServletRequest request) Notify this BlockingPolicy that the given thread is not blocked anymore.

Method Detail

block

long block(java.lang.Thread thread,
           long userDuration,
           UWSJob job,
           JobOwner user,
           javax.servlet.http.HttpServletRequest request)
    throws java.lang.NullPointerException

Notify this BlockingPolicy that the given thread is going to be blocked for the specified duration. This function then decides how long the given thread must really wait before resuming.

The parameter "userDuration" and the returned value are durations expressed in seconds. Both follow the same rules:

• If < 0, the request will wait theoretically indefinitely.
• If 0, the request will return immediately ; no wait.
• If > 0, the request will wait for the specified amount of seconds.

Since a timeout or another special behavior may be chosen by this BlockingPolicy, the returned value may be different from the user's asked duration. The value that should be taken into account is obviously the returned one.

IMPORTANT: This function may UNblock an older request/thread, in function of the strategy chosen/implemented by this BlockingPolicy.

Parameters:

thread - Thread that is going to be blocked. MUST NOT be NULL. If NULL this function will either do nothing and return 0 (no blocking) or throw a NullPointerException.

userDuration - Waiting duration (in seconds) asked by the user. < 0 means indefinite, 0 means no wait and > 0 means waiting for the specified amount of seconds.

job - The job associated with the thread. Should not be NULL.

user - The user who asked for the blocking behavior. If NULL, the request will be concerned as anonymous and a decision to identify the user (e.g. use the IP address) may be chosen by the BlockingPolicy implementation if required.

request - The request which is going to be blocked. Should not be NULL.

Returns:

The real duration (in seconds) that the UWS service must wait before returning a response to the given HTTP request. < 0 means indefinite, 0 means no wait and > 0 means waiting for the specified amount of seconds.

Throws:

java.lang.NullPointerException - If the given thread is NULL.

unblocked

void unblocked(java.lang.Thread unblockedThread,
               UWSJob job,
               JobOwner user,
               javax.servlet.http.HttpServletRequest request)

Notify this BlockingPolicy that the given thread is not blocked anymore.

Parameters:

unblockedThread - Thread that is not blocked any more. MUST be NOT NULL.

job - The job associated with the unblocked Thread. Should not be NULL.

user - The user who originally asked for the blocking behavior. If NULL, the request will be concerned as anonymous and a decision to identify the user (e.g. use the IP address) may be chosen by the BlockingPolicy implementation if required.

request - The request which has been unblocked. Should not be NULL.