com.google.appengine.api.datastore.dev
Class DefaultHighRepJobPolicy

java.lang.Object
  com.google.appengine.api.datastore.dev.DefaultHighRepJobPolicy

All Implemented Interfaces:

HighRepJobPolicy

public class DefaultHighRepJobPolicy
extends java.lang.Object
implements HighRepJobPolicy

An implementation of HighRepJobPolicy in which a user-defined percentage of jobs do not apply. The percentage applies to both new (initial write) and existing (roll forward) jobs. The user can also provide a random seed, which can be used to make the behavior of this class deterministic in tests.

Field Summary

static java.lang.String	RANDOM_SEED_PROPERTY A long that will be used as the seed for the Random that determines whether or not a job application attempt fails.
static java.lang.String	UNAPPLIED_JOB_PERCENTAGE_PROPERTY A float >= 0 and <= 100 representing the percentage of job application attempts that will fail.

Constructor Summary

DefaultHighRepJobPolicy(long unappliedJobSeed, float unappliedJobPercentage)
Constructs a DefaultHighRepJobPolicy.

Method Summary

boolean	shouldApplyNewJob(com.google.appengine.api.datastore.Key entityGroup)
boolean	shouldRollForwardExistingJob(com.google.appengine.api.datastore.Key entityGroup)

Methods inherited from class java.lang.Object

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

Field Detail

RANDOM_SEED_PROPERTY

public static final java.lang.String RANDOM_SEED_PROPERTY

A long that will be used as the seed for the Random that determines whether or not a job application attempt fails. Must be parsable via Long.parseLong(String). If not provided we use the current time (in millis) as the seed.

See Also:

Constant Field Values

UNAPPLIED_JOB_PERCENTAGE_PROPERTY

public static final java.lang.String UNAPPLIED_JOB_PERCENTAGE_PROPERTY

A float >= 0 and <= 100 representing the percentage of job application attempts that will fail. Must be parsable via Float.parseFloat(String). Any portion of the value beyond two decimal places will be truncated. If not provided we set the percentage to 0, which yields the master/slave consistency model.

See Also:

Constant Field Values

Constructor Detail

DefaultHighRepJobPolicy

public DefaultHighRepJobPolicy(long unappliedJobSeed,
                               float unappliedJobPercentage)

Constructs a DefaultHighRepJobPolicy.

Parameters:

unappliedJobSeed - The seed to use for random number generation.

unappliedJobPercentage - The percentage of jobs that should fail to apply. This percentage applies to both new jobs and attempts to roll forward existing unapplied jobs.

Method Detail

shouldApplyNewJob

public boolean shouldApplyNewJob(com.google.appengine.api.datastore.Key entityGroup)

Specified by:

shouldApplyNewJob in interface HighRepJobPolicy

Parameters:

entityGroup - A unique identifier for the entity group.

Returns:

true if the new job should apply according to the policy, false otherwise.

shouldRollForwardExistingJob

public boolean shouldRollForwardExistingJob(com.google.appengine.api.datastore.Key entityGroup)

Specified by:

shouldRollForwardExistingJob in interface HighRepJobPolicy

Parameters:

entityGroup - A unique identifier for the entity group.

Returns:

true if the existing job should roll forward according to the policy, false otherwise.