org.apache.hadoop.hbase

Class Waiter

java.lang.Object

org.apache.hadoop.hbase.Waiter

@InterfaceAudience.Private
public final class Waiter
extends Object

A class that provides a standard waitFor pattern See details at https://issues.apache.org/jira/browse/HBASE-7384

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Waiter.ExplainingPredicate<E extends Exception> A mixin interface, can be used with Waiter to explain failed state.
static interface	Waiter.Predicate<E extends Exception> A predicate 'closure' used by the waitFor(Configuration, long, Predicate) and waitFor(Configuration, long, Predicate) and {@link Waiter#waitFor(Configuration, long, long, boolean, Predicate) methods.

Field Summary

Fields

Modifier and Type	Field and Description
static String	HBASE_TEST_WAIT_FOR_RATIO System property name whose value is a scale factor to increase time out values dynamically used in sleep(Configuration, long), waitFor(Configuration, long, Predicate), waitFor(Configuration, long, long, Predicate), and waitFor(Configuration, long, long, boolean, Predicate) method The actual time out value will equal to hbase.test.wait.for.ratio * passed-in timeout

Method Summary

Modifier and Type	Method and Description
static String	getExplanation(Waiter.Predicate explain)
static float	getWaitForRatio(Configuration conf) Returns the 'wait for ratio' used in the sleep(Configuration, long), waitFor(Configuration, long, Predicate), waitFor(Configuration, long, long, Predicate) and waitFor(Configuration, long, long, boolean, Predicate) methods of the class This is useful to dynamically adjust max time out values when same test cases run in different test machine settings without recompiling & re-deploying code.
static void	sleep(Configuration conf, long time) Makes the current thread sleep for the duration equal to the specified time in milliseconds multiplied by the getWaitForRatio(Configuration).
static <E extends Exception> long	waitFor(Configuration conf, long timeout, long interval, boolean failIfTimeout, Waiter.Predicate<E> predicate) Waits up to the duration equal to the specified timeout multiplied by the getWaitForRatio(Configuration) for the given Waiter.Predicate to become true, failing the test if the timeout is reached, the Predicate is still false and failIfTimeout is set as true.
static <E extends Exception> long	waitFor(Configuration conf, long timeout, long interval, Waiter.Predicate<E> predicate) Waits up to the duration equal to the specified timeout multiplied by the getWaitForRatio(Configuration) for the given Waiter.Predicate to become true, failing the test if the timeout is reached and the Predicate is still false.
static <E extends Exception> long	waitFor(Configuration conf, long timeout, Waiter.Predicate<E> predicate) Waits up to the duration equal to the specified timeout multiplied by the getWaitForRatio(Configuration) for the given Waiter.Predicate to become true, failing the test if the timeout is reached and the Predicate is still false.

Methods inherited from class java.lang.Object

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

Field Detail

HBASE_TEST_WAIT_FOR_RATIO

public static final String HBASE_TEST_WAIT_FOR_RATIO

System property name whose value is a scale factor to increase time out values dynamically used in sleep(Configuration, long), waitFor(Configuration, long, Predicate), waitFor(Configuration, long, long, Predicate), and waitFor(Configuration, long, long, boolean, Predicate) method

The actual time out value will equal to hbase.test.wait.for.ratio * passed-in timeout

See Also:

Constant Field Values

Method Detail

getWaitForRatio

public static float getWaitForRatio(Configuration conf)

Returns the 'wait for ratio' used in the sleep(Configuration, long), waitFor(Configuration, long, Predicate), waitFor(Configuration, long, long, Predicate) and waitFor(Configuration, long, long, boolean, Predicate) methods of the class

This is useful to dynamically adjust max time out values when same test cases run in different test machine settings without recompiling & re-deploying code.

The value is obtained from the Java System property or configuration setting hbase.test.wait.for.ratio which defaults to 1.

Parameters:

conf - the configuration

Returns:

the 'wait for ratio' for the current test run.

sleep

public static void sleep(Configuration conf,
                         long time)

Makes the current thread sleep for the duration equal to the specified time in milliseconds multiplied by the getWaitForRatio(Configuration).

Parameters:

conf - the configuration

time - the number of milliseconds to sleep.

waitFor

public static <E extends Exception> long waitFor(Configuration conf,
                                                 long timeout,
                                                 Waiter.Predicate<E> predicate)
                                          throws E extends Exception

Waits up to the duration equal to the specified timeout multiplied by the getWaitForRatio(Configuration) for the given Waiter.Predicate to become true, failing the test if the timeout is reached and the Predicate is still false.

Parameters:

conf - the configuration

timeout - the timeout in milliseconds to wait for the predicate.

predicate - the predicate to evaluate.

Returns:

the effective wait, in milli-seconds until the predicate becomes true or wait is interrupted otherwise -1 when times out

Throws:

E extends Exception

waitFor

public static <E extends Exception> long waitFor(Configuration conf,
                                                 long timeout,
                                                 long interval,
                                                 Waiter.Predicate<E> predicate)
                                          throws E extends Exception

Waits up to the duration equal to the specified timeout multiplied by the getWaitForRatio(Configuration) for the given Waiter.Predicate to become true, failing the test if the timeout is reached and the Predicate is still false.

Parameters:

conf - the configuration

timeout - the max timeout in milliseconds to wait for the predicate.

interval - the interval in milliseconds to evaluate predicate.

predicate - the predicate to evaluate.

Returns:

the effective wait, in milli-seconds until the predicate becomes true or wait is interrupted otherwise -1 when times out

Throws:

E extends Exception

waitFor

public static <E extends Exception> long waitFor(Configuration conf,
                                                 long timeout,
                                                 long interval,
                                                 boolean failIfTimeout,
                                                 Waiter.Predicate<E> predicate)
                                          throws E extends Exception

Waits up to the duration equal to the specified timeout multiplied by the getWaitForRatio(Configuration) for the given Waiter.Predicate to become true, failing the test if the timeout is reached, the Predicate is still false and failIfTimeout is set as true.

Parameters:

conf - the configuration

timeout - the timeout in milliseconds to wait for the predicate.

interval - the interval in milliseconds to evaluate predicate.

failIfTimeout - indicates if should fail current test case when times out.

predicate - the predicate to evaluate.

Returns:

the effective wait, in milli-seconds until the predicate becomes true or wait is interrupted otherwise -1 when times out

Throws:

E extends Exception

getExplanation

public static String getExplanation(Waiter.Predicate explain)