Package org.apache.druid.common.guava

Class GuavaUtils

java.lang.Object

org.apache.druid.common.guava.GuavaUtils

public class GuavaUtils
extends Object

Constructor Summary

Constructors

Constructor	Description
GuavaUtils()

Method Summary

Modifier and Type	Method	Description
static <F extends Future<?>> void	cancelAll(boolean mayInterruptIfRunning, Future<?> combinedFuture, List<F> futures)	Cancel futures manually, because sometime we can't cancel all futures in {code com.google.common.util.concurrent.Futures.CombinedFuture} automatically.
static <T> T	firstNonNull(T lhs, T rhs)	If first argument is not null, return it, else return the other argument.
static <T extends Enum<T>> T	getEnumIfPresent(Class<T> enumClass, String value)	Like Guava's Enums.getIfPresent, with some differences.
static Long	tryParseLong(String string)	To fix semantic difference of Longs.tryParse() from Long.parseLong (Longs.tryParse() returns null for '+' started value)

Methods inherited from class java.lang.Object

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

Constructor Detail

GuavaUtils

public GuavaUtils()

Method Detail

tryParseLong

@Nullable
public static Long tryParseLong(@Nullable
                                String string)

To fix semantic difference of Longs.tryParse() from Long.parseLong (Longs.tryParse() returns null for '+' started value)

getEnumIfPresent

@Nullable
public static <T extends Enum<T>> T getEnumIfPresent(Class<T> enumClass,
                                                     String value)

Like Guava's Enums.getIfPresent, with some differences.

• Returns nullable rather than Optional
• Does not require Guava 12

firstNonNull

@Nullable
public static <T> T firstNonNull(@Nullable
                                 T lhs,
                                 @Nullable
                                 T rhs)

If first argument is not null, return it, else return the other argument. Sort of like {@link com.google.common.base.Objects#firstNonNull(T, T)} except will not explode if both arguments are null.

cancelAll

public static <F extends Future<?>> void cancelAll(boolean mayInterruptIfRunning,
                                                   @Nullable
                                                   Future<?> combinedFuture,
                                                   List<F> futures)

Cancel futures manually, because sometime we can't cancel all futures in {code com.google.common.util.concurrent.Futures.CombinedFuture} automatically. Especially when we call {@link static ListenableFuture> com.google.common.util.concurrent.Futures#allAsList(Iterable> futures)} to create a batch of future.

Parameters:

mayInterruptIfRunning - true if the thread executing this task should be interrupted; otherwise, in-progress tasks are allowed to complete

combinedFuture - The combinedFuture that associated with futures

futures - The futures that we want to cancel