uws.service.wait

Class LimitedBlockingPolicy

java.lang.Object

uws.service.wait.LimitedBlockingPolicy

All Implemented Interfaces:

BlockingPolicy

Direct Known Subclasses:

UserLimitedBlockingPolicy

public class LimitedBlockingPolicy
extends java.lang.Object
implements BlockingPolicy

In this BlockingPolicy, the blocking is limited by a maximum waiting time. Thus, unlimited blocking is prevented.

More concretely, if no timeout is specified by the user, timeout is returned.

If at creation of this policy no timeout is specified, a default one is set: DEFAULT_TIMEOUT (= 60L seconds).

Since:

4.3

Version:

4.3 (11/2017)

Author:

Grégory Mantelet (ARI)

Field Summary

Fields

Modifier and Type	Field and Description
static long	DEFAULT_TIMEOUT Default timeout (in seconds) set by this policy at creation if none is specified.
protected long	timeout Maximum blocking duration (in seconds).

Constructor Summary

Constructors

Constructor and Description
LimitedBlockingPolicy() Build a blocking policy with the default timeout (= 60L seconds).
LimitedBlockingPolicy(long timeout) Build a BlockingPolicy which will limit blocking duration to the given value.

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.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_TIMEOUT

public static final long DEFAULT_TIMEOUT

Default timeout (in seconds) set by this policy at creation if none is specified.

See Also:

Constant Field Values

timeout

protected long timeout

Maximum blocking duration (in seconds). This attribute is set by default to DEFAULT_TIMEOUT.

Constructor Detail

LimitedBlockingPolicy

public LimitedBlockingPolicy()

Build a blocking policy with the default timeout (= 60L seconds).

LimitedBlockingPolicy

public LimitedBlockingPolicy(long timeout)

Build a BlockingPolicy which will limit blocking duration to the given value.

IMPORTANT: If timeout is < 0, the default timeout (i.e. 60L) will be set automatically by this constructor.

Parameters:

timeout - Maximum blocking duration (in seconds).

Method Detail

block

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

Description copied from interface: BlockingPolicy

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.

Specified by:

block in interface 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.

unblocked

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

Description copied from interface: BlockingPolicy

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

Specified by:

unblocked in interface BlockingPolicy

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.