Package org.apache.hadoop.hbase

Class Waiter

java.lang.Object

org.apache.hadoop.hbase.Waiter

@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	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 waitFor(Configuration, long, long, boolean, Predicate) methods.

Field Summary

Fields

Modifier and Type	Field	Description
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
private static float	HBASE_WAIT_FOR_RATIO_DEFAULT
private static final org.slf4j.Logger	LOG
private static float	waitForRatio

Constructor Summary

Constructors

Modifier	Constructor	Description
private	Waiter()

Method Summary

Modifier and Type	Method	Description
static String	getExplanation(Waiter.Predicate<?> explain)
static float	getWaitForRatio(org.apache.hadoop.conf.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
static void	sleep(org.apache.hadoop.conf.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(org.apache.hadoop.conf.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(org.apache.hadoop.conf.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(org.apache.hadoop.conf.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 Details

LOG

private static final org.slf4j.Logger LOG

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

HBASE_WAIT_FOR_RATIO_DEFAULT

private static float HBASE_WAIT_FOR_RATIO_DEFAULT

waitForRatio

private static float waitForRatio

Constructor Details

Waiter

private Waiter()

Method Details

getWaitForRatio

public static float getWaitForRatio(org.apache.hadoop.conf.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(org.apache.hadoop.conf.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(org.apache.hadoop.conf.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.

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

waitFor

public static <E extends Exception> long waitFor(org.apache.hadoop.conf.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.

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

waitFor

public static <E extends Exception> long waitFor(org.apache.hadoop.conf.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.

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

getExplanation

public static String getExplanation(Waiter.Predicate<?> explain)