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/**
* Copyright (c) 2016-present, RxJava Contributors.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
* compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License is
* distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
* the License for the specific language governing permissions and limitations under the License.
*/
package io.reactivex.common;
import io.reactivex.common.annotations.Experimental;
import io.reactivex.common.annotations.NonNull;
import io.reactivex.common.annotations.Nullable;
import io.reactivex.common.exceptions.*;
import io.reactivex.common.functions.BiFunction;
import io.reactivex.common.functions.BooleanSupplier;
import io.reactivex.common.functions.Consumer;
import io.reactivex.common.functions.Function;
import io.reactivex.common.internal.functions.ObjectHelper;
import io.reactivex.common.internal.schedulers.ComputationScheduler;
import io.reactivex.common.internal.schedulers.IoScheduler;
import io.reactivex.common.internal.schedulers.NewThreadScheduler;
import io.reactivex.common.internal.schedulers.SingleScheduler;
import io.reactivex.common.internal.utils.ExceptionHelper;
import io.reactivex.common.Schedulers;
import java.lang.Thread.UncaughtExceptionHandler;
import java.util.concurrent.Callable;
import java.util.concurrent.ThreadFactory;
/**
* Utility class to inject handlers to certain standard RxJava operations.
*/
public final class RxJavaCommonPlugins {
@Nullable
static volatile Consumer errorHandler;
@Nullable
static volatile Function onScheduleHandler;
@Nullable
static volatile Function, ? extends Scheduler> onInitComputationHandler;
@Nullable
static volatile Function, ? extends Scheduler> onInitSingleHandler;
@Nullable
static volatile Function, ? extends Scheduler> onInitIoHandler;
@Nullable
static volatile Function, ? extends Scheduler> onInitNewThreadHandler;
@Nullable
static volatile Function onComputationHandler;
@Nullable
static volatile Function onSingleHandler;
@Nullable
static volatile Function onIoHandler;
@Nullable
static volatile Function onNewThreadHandler;
@Nullable
static volatile BooleanSupplier onBeforeBlocking;
/** Prevents changing the plugins. */
static volatile boolean lockdown;
/**
* If true, attempting to run a blockingX operation on a (by default)
* computation or single scheduler will throw an IllegalStateException.
*/
static volatile boolean failNonBlockingScheduler;
/**
* Prevents changing the plugins from then on.
* This allows container-like environments to prevent clients
* messing with plugins.
*/
public static void lockdown() {
lockdown = true;
}
/**
* Returns true if the plugins were locked down.
* @return true if the plugins were locked down
*/
public static boolean isLockdown() {
return lockdown;
}
/**
* Enables or disables the blockingX operators to fail
* with an IllegalStateException on a non-blocking
* scheduler such as computation or single.
* @param enable enable or disable the feature
* @since 2.0.5 - experimental
*/
@Experimental
public static void setFailOnNonBlockingScheduler(boolean enable) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
failNonBlockingScheduler = enable;
}
/**
* Returns true if the blockingX operators fail
* with an IllegalStateException on a non-blocking scheduler
* such as computation or single.
* @return true if the blockingX operators fail on a non-blocking scheduler
* @since 2.0.5 - experimental
*/
@Experimental
public static boolean isFailOnNonBlockingScheduler() {
return failNonBlockingScheduler;
}
/**
* Returns the current hook function.
* @return the hook function, may be null
*/
@Nullable
public static Function getComputationSchedulerHandler() {
return onComputationHandler;
}
/**
* Returns the a hook consumer.
* @return the hook consumer, may be null
*/
@Nullable
public static Consumer getErrorHandler() {
return errorHandler;
}
/**
* Returns the current hook function.
* @return the hook function, may be null
*/
@Nullable
public static Function, ? extends Scheduler> getInitComputationSchedulerHandler() {
return onInitComputationHandler;
}
/**
* Returns the current hook function.
* @return the hook function, may be null
*/
@Nullable
public static Function, ? extends Scheduler> getInitIoSchedulerHandler() {
return onInitIoHandler;
}
/**
* Returns the current hook function.
* @return the hook function, may be null
*/
@Nullable
public static Function, ? extends Scheduler> getInitNewThreadSchedulerHandler() {
return onInitNewThreadHandler;
}
/**
* Returns the current hook function.
* @return the hook function, may be null
*/
@Nullable
public static Function, ? extends Scheduler> getInitSingleSchedulerHandler() {
return onInitSingleHandler;
}
/**
* Returns the current hook function.
* @return the hook function, may be null
*/
@Nullable
public static Function getIoSchedulerHandler() {
return onIoHandler;
}
/**
* Returns the current hook function.
* @return the hook function, may be null
*/
@Nullable
public static Function getNewThreadSchedulerHandler() {
return onNewThreadHandler;
}
/**
* Returns the current hook function.
* @return the hook function, may be null
*/
@Nullable
public static Function getScheduleHandler() {
return onScheduleHandler;
}
/**
* Returns the current hook function.
* @return the hook function, may be null
*/
@Nullable
public static Function getSingleSchedulerHandler() {
return onSingleHandler;
}
/**
* Calls the associated hook function.
* @param defaultScheduler a {@link Callable} which returns the hook's input value
* @return the value returned by the hook, not null
* @throws NullPointerException if the callable parameter or its result are null
*/
@NonNull
public static Scheduler initComputationScheduler(@NonNull Callable defaultScheduler) {
ObjectHelper.requireNonNull(defaultScheduler, "Scheduler Callable can't be null");
Function, ? extends Scheduler> f = onInitComputationHandler;
if (f == null) {
return callRequireNonNull(defaultScheduler);
}
return applyRequireNonNull(f, defaultScheduler); // JIT will skip this
}
/**
* Calls the associated hook function.
* @param defaultScheduler a {@link Callable} which returns the hook's input value
* @return the value returned by the hook, not null
* @throws NullPointerException if the callable parameter or its result are null
*/
@NonNull
public static Scheduler initIoScheduler(@NonNull Callable defaultScheduler) {
ObjectHelper.requireNonNull(defaultScheduler, "Scheduler Callable can't be null");
Function, ? extends Scheduler> f = onInitIoHandler;
if (f == null) {
return callRequireNonNull(defaultScheduler);
}
return applyRequireNonNull(f, defaultScheduler);
}
/**
* Calls the associated hook function.
* @param defaultScheduler a {@link Callable} which returns the hook's input value
* @return the value returned by the hook, not null
* @throws NullPointerException if the callable parameter or its result are null
*/
@NonNull
public static Scheduler initNewThreadScheduler(@NonNull Callable defaultScheduler) {
ObjectHelper.requireNonNull(defaultScheduler, "Scheduler Callable can't be null");
Function, ? extends Scheduler> f = onInitNewThreadHandler;
if (f == null) {
return callRequireNonNull(defaultScheduler);
}
return applyRequireNonNull(f, defaultScheduler);
}
/**
* Calls the associated hook function.
* @param defaultScheduler a {@link Callable} which returns the hook's input value
* @return the value returned by the hook, not null
* @throws NullPointerException if the callable parameter or its result are null
*/
@NonNull
public static Scheduler initSingleScheduler(@NonNull Callable defaultScheduler) {
ObjectHelper.requireNonNull(defaultScheduler, "Scheduler Callable can't be null");
Function, ? extends Scheduler> f = onInitSingleHandler;
if (f == null) {
return callRequireNonNull(defaultScheduler);
}
return applyRequireNonNull(f, defaultScheduler);
}
/**
* Calls the associated hook function.
* @param defaultScheduler the hook's input value
* @return the value returned by the hook
*/
@NonNull
public static Scheduler onComputationScheduler(@NonNull Scheduler defaultScheduler) {
Function f = onComputationHandler;
if (f == null) {
return defaultScheduler;
}
return apply(f, defaultScheduler);
}
/**
* Called when an undeliverable error occurs.
* @param error the error to report
*/
public static void onError(@NonNull Throwable error) {
Consumer f = errorHandler;
if (error == null) {
error = new NullPointerException("onError called with null. Null values are generally not allowed in 2.x operators and sources.");
} else {
if (!isBug(error)) {
error = new UndeliverableException(error);
}
}
if (f != null) {
try {
f.accept(error);
return;
} catch (Throwable e) {
// Exceptions.throwIfFatal(e); TODO decide
e.printStackTrace(); // NOPMD
uncaught(e);
}
}
error.printStackTrace(); // NOPMD
uncaught(error);
}
/**
* Checks if the given error is one of the already named
* bug cases that should pass through {@link #onError(Throwable)}
* as is.
* @param error the error to check
* @return true if the error should pass through, false if
* it may be wrapped into an UndeliverableException
*/
static boolean isBug(Throwable error) {
// user forgot to add the onError handler in subscribe
if (error instanceof OnErrorNotImplementedException) {
return true;
}
// the sender didn't honor the request amount
// it's either due to an operator bug or concurrent onNext
if (error instanceof MissingBackpressureException) {
return true;
}
// general protocol violations
// it's either due to an operator bug or concurrent onNext
if (error instanceof IllegalStateException) {
return true;
}
// nulls are generally not allowed
// likely an operator bug or missing null-check
if (error instanceof NullPointerException) {
return true;
}
// bad arguments, likely invalid user input
if (error instanceof IllegalArgumentException) {
return true;
}
// Crash while handling an exception
if (error instanceof CompositeException) {
return true;
}
// everything else is probably due to lifecycle limits
return false;
}
static void uncaught(@NonNull Throwable error) {
Thread currentThread = Thread.currentThread();
UncaughtExceptionHandler handler = currentThread.getUncaughtExceptionHandler();
handler.uncaughtException(currentThread, error);
}
/**
* Calls the associated hook function.
* @param defaultScheduler the hook's input value
* @return the value returned by the hook
*/
@NonNull
public static Scheduler onIoScheduler(@NonNull Scheduler defaultScheduler) {
Function f = onIoHandler;
if (f == null) {
return defaultScheduler;
}
return apply(f, defaultScheduler);
}
/**
* Calls the associated hook function.
* @param defaultScheduler the hook's input value
* @return the value returned by the hook
*/
@NonNull
public static Scheduler onNewThreadScheduler(@NonNull Scheduler defaultScheduler) {
Function f = onNewThreadHandler;
if (f == null) {
return defaultScheduler;
}
return apply(f, defaultScheduler);
}
/**
* Called when a task is scheduled.
* @param run the runnable instance
* @return the replacement runnable
*/
@NonNull
public static Runnable onSchedule(@NonNull Runnable run) {
Function f = onScheduleHandler;
if (f == null) {
return run;
}
return apply(f, run);
}
/**
* Calls the associated hook function.
* @param defaultScheduler the hook's input value
* @return the value returned by the hook
*/
@NonNull
public static Scheduler onSingleScheduler(@NonNull Scheduler defaultScheduler) {
Function f = onSingleHandler;
if (f == null) {
return defaultScheduler;
}
return apply(f, defaultScheduler);
}
/**
* Removes all handlers and resets to default behavior.
*/
public static void reset() {
setErrorHandler(null);
setScheduleHandler(null);
setComputationSchedulerHandler(null);
setInitComputationSchedulerHandler(null);
setIoSchedulerHandler(null);
setInitIoSchedulerHandler(null);
setSingleSchedulerHandler(null);
setInitSingleSchedulerHandler(null);
setNewThreadSchedulerHandler(null);
setInitNewThreadSchedulerHandler(null);
setFailOnNonBlockingScheduler(false);
setOnBeforeBlocking(null);
}
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed
*/
public static void setComputationSchedulerHandler(@Nullable Function handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onComputationHandler = handler;
}
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed
*/
public static void setErrorHandler(@Nullable Consumer handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
errorHandler = handler;
}
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed, but the function may not return null
*/
public static void setInitComputationSchedulerHandler(@Nullable Function, ? extends Scheduler> handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onInitComputationHandler = handler;
}
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed, but the function may not return null
*/
public static void setInitIoSchedulerHandler(@Nullable Function, ? extends Scheduler> handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onInitIoHandler = handler;
}
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed, but the function may not return null
*/
public static void setInitNewThreadSchedulerHandler(@Nullable Function, ? extends Scheduler> handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onInitNewThreadHandler = handler;
}
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed, but the function may not return null
*/
public static void setInitSingleSchedulerHandler(@Nullable Function, ? extends Scheduler> handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onInitSingleHandler = handler;
}
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed
*/
public static void setIoSchedulerHandler(@Nullable Function handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onIoHandler = handler;
}
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed
*/
public static void setNewThreadSchedulerHandler(@Nullable Function handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onNewThreadHandler = handler;
}
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed
*/
public static void setScheduleHandler(@Nullable Function handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onScheduleHandler = handler;
}
/**
* Sets the specific hook function.
* @param handler the hook function to set, null allowed
*/
public static void setSingleSchedulerHandler(@Nullable Function handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onSingleHandler = handler;
}
/**
* Revokes the lockdown, only for testing purposes.
*/
/* test. */static void unlock() {
lockdown = false;
}
/**
* Called before an operator attempts a blocking operation
* such as awaiting a condition or signal
* and should return true to indicate the operator
* should not block but throw an IllegalArgumentException.
* @return true if the blocking should be prevented
* @see #setFailOnNonBlockingScheduler(boolean)
* @since 2.0.5 - experimental
*/
@Experimental
public static boolean onBeforeBlocking() {
BooleanSupplier f = onBeforeBlocking;
if (f != null) {
try {
return f.getAsBoolean();
} catch (Throwable ex) {
throw ExceptionHelper.wrapOrThrow(ex);
}
}
return false;
}
/**
* Set the handler that is called when an operator attempts a blocking
* await; the handler should return true to prevent the blocking
* and to signal an IllegalStateException instead.
* @param handler the handler to set, null resets to the default handler
* that always returns false
* @see #onBeforeBlocking()
* @since 2.0.5 - experimental
*/
@Experimental
public static void setOnBeforeBlocking(@Nullable BooleanSupplier handler) {
if (lockdown) {
throw new IllegalStateException("Plugins can't be changed anymore");
}
onBeforeBlocking = handler;
}
/**
* Returns the current blocking handler or null if no custom handler
* is set.
* @return the current blocking handler or null if not specified
* @since 2.0.5 - experimental
*/
@Experimental
@Nullable
public static BooleanSupplier getOnBeforeBlocking() {
return onBeforeBlocking;
}
/**
* Create an instance of the default {@link Scheduler} used for {@link Schedulers#computation()}
* except using {@code threadFactory} for thread creation.
* @param threadFactory thread factory to use for creating worker threads. Note that this takes precedence over any
* system properties for configuring new thread creation. Cannot be null.
* @return the created Scheduler instance
* @since 2.0.5 - experimental
*/
@Experimental
@NonNull
public static Scheduler createComputationScheduler(@NonNull ThreadFactory threadFactory) {
return new ComputationScheduler(ObjectHelper.requireNonNull(threadFactory, "threadFactory is null"));
}
/**
* Create an instance of the default {@link Scheduler} used for {@link Schedulers#io()}
* except using {@code threadFactory} for thread creation.
* @param threadFactory thread factory to use for creating worker threads. Note that this takes precedence over any
* system properties for configuring new thread creation. Cannot be null.
* @return the created Scheduler instance
* @since 2.0.5 - experimental
*/
@Experimental
@NonNull
public static Scheduler createIoScheduler(@NonNull ThreadFactory threadFactory) {
return new IoScheduler(ObjectHelper.requireNonNull(threadFactory, "threadFactory is null"));
}
/**
* Create an instance of the default {@link Scheduler} used for {@link Schedulers#newThread()}
* except using {@code threadFactory} for thread creation.
* @param threadFactory thread factory to use for creating worker threads. Note that this takes precedence over any
* system properties for configuring new thread creation. Cannot be null.
* @return the created Scheduler instance
* @since 2.0.5 - experimental
*/
@Experimental
@NonNull
public static Scheduler createNewThreadScheduler(@NonNull ThreadFactory threadFactory) {
return new NewThreadScheduler(ObjectHelper.requireNonNull(threadFactory, "threadFactory is null"));
}
/**
* Create an instance of the default {@link Scheduler} used for {@link Schedulers#single()}
* except using {@code threadFactory} for thread creation.
* @param threadFactory thread factory to use for creating worker threads. Note that this takes precedence over any
* system properties for configuring new thread creation. Cannot be null.
* @return the created Scheduler instance
* @since 2.0.5 - experimental
*/
@Experimental
@NonNull
public static Scheduler createSingleScheduler(@NonNull ThreadFactory threadFactory) {
return new SingleScheduler(ObjectHelper.requireNonNull(threadFactory, "threadFactory is null"));
}
/**
* Wraps the call to the function in try-catch and propagates thrown
* checked exceptions as RuntimeException.
* @param the input type
* @param the output type
* @param f the function to call, not null (not verified)
* @param t the parameter value to the function
* @return the result of the function call
*/
@NonNull
static R apply(@NonNull Function f, @NonNull T t) {
try {
return f.apply(t);
} catch (Throwable ex) {
throw ExceptionHelper.wrapOrThrow(ex);
}
}
/**
* Wraps the call to the function in try-catch and propagates thrown
* checked exceptions as RuntimeException.
* @param the first input type
* @param the second input type
* @param the output type
* @param f the function to call, not null (not verified)
* @param t the first parameter value to the function
* @param u the second parameter value to the function
* @return the result of the function call
*/
@NonNull
static R apply(@NonNull BiFunction f, @NonNull T t, @NonNull U u) {
try {
return f.apply(t, u);
} catch (Throwable ex) {
throw ExceptionHelper.wrapOrThrow(ex);
}
}
/**
* Wraps the call to the Scheduler creation callable in try-catch and propagates thrown
* checked exceptions as RuntimeException and enforces that result is not null.
* @param s the {@link Callable} which returns a {@link Scheduler}, not null (not verified). Cannot return null
* @return the result of the callable call, not null
* @throws NullPointerException if the callable parameter returns null
*/
@NonNull
static Scheduler callRequireNonNull(@NonNull Callable s) {
try {
return ObjectHelper.requireNonNull(s.call(), "Scheduler Callable result can't be null");
} catch (Throwable ex) {
throw ExceptionHelper.wrapOrThrow(ex);
}
}
/**
* Wraps the call to the Scheduler creation function in try-catch and propagates thrown
* checked exceptions as RuntimeException and enforces that result is not null.
* @param f the function to call, not null (not verified). Cannot return null
* @param s the parameter value to the function
* @return the result of the function call, not null
* @throws NullPointerException if the function parameter returns null
*/
@NonNull
static Scheduler applyRequireNonNull(@NonNull Function, ? extends Scheduler> f, Callable s) {
return ObjectHelper.requireNonNull(apply(f, s), "Scheduler Callable result can't be null");
}
/** Helper class, no instances. */
private RxJavaCommonPlugins() {
throw new IllegalStateException("No instances!");
}
}