Timer Class
Definition
Important
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A facility for threads to schedule tasks for future execution in a background thread.
[Android.Runtime.Register("java/util/Timer", DoNotGenerateAcw=true)]
public class Timer : Java.Lang.Object[<Android.Runtime.Register("java/util/Timer", DoNotGenerateAcw=true)>]
type Timer = class
inherit Object- Inheritance
- Attributes
Remarks
A facility for threads to schedule tasks for future execution in a background thread. Tasks may be scheduled for one-time execution, or for repeated execution at regular intervals.
Corresponding to each Timer object is a single background thread that is used to execute all of the timer's tasks, sequentially. Timer tasks should complete quickly. If a timer task takes excessive time to complete, it "hogs" the timer's task execution thread. This can, in turn, delay the execution of subsequent tasks, which may "bunch up" and execute in rapid succession when (and if) the offending task finally completes.
After the last live reference to a Timer object goes away and all outstanding tasks have completed execution, the timer's task execution thread terminates gracefully (and becomes subject to garbage collection). However, this can take arbitrarily long to occur. By default, the task execution thread does not run as a daemon thread, so it is capable of keeping an application from terminating. If a caller wants to terminate a timer's task execution thread rapidly, the caller should invoke the timer's cancel method.
If the timer's task execution thread terminates unexpectedly, for example, because its stop method is invoked, any further attempt to schedule a task on the timer will result in an IllegalStateException, as if the timer's cancel method had been invoked.
This class is thread-safe: multiple threads can share a single Timer object without the need for external synchronization.
This class does not offer real-time guarantees: it schedules tasks using the Object.wait(long) method.
Java 5.0 introduced the java.util.concurrent package and one of the concurrency utilities therein is the java.util.concurrent.ScheduledThreadPoolExecutor ScheduledThreadPoolExecutor which is a thread pool for repeatedly executing tasks at a given rate or delay. It is effectively a more versatile replacement for the Timer/TimerTask combination, as it allows multiple service threads, accepts various time units, and doesn't require subclassing TimerTask (just implement Runnable). Configuring ScheduledThreadPoolExecutor with one thread makes it equivalent to Timer.
Implementation note: This class scales to large numbers of concurrently scheduled tasks (thousands should present no problem). Internally, it uses a binary heap to represent its task queue, so the cost to schedule a task is O(log n), where n is the number of concurrently scheduled tasks.
Implementation note: All constructors start a timer thread.
Added in 1.3.
Java documentation for java.util.Timer.
Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.
Constructors
| Timer() |
Creates a new timer. |
| Timer(Boolean) |
Creates a new timer whose associated thread may be specified to Thread#setDaemon run as a daemon. |
| Timer(IntPtr, JniHandleOwnership) |
A constructor used when creating managed representations of JNI objects; called by the runtime. |
| Timer(String, Boolean) |
Creates a new timer whose associated thread has the specified name, and may be specified to Thread#setDaemon run as a daemon. |
| Timer(String) |
Creates a new timer whose associated thread has the specified name. |
Properties
| Class |
Returns the runtime class of this |
| Handle |
The handle to the underlying Android instance. (Inherited from Object) |
| JniIdentityHashCode | (Inherited from Object) |
| JniPeerMembers | |
| PeerReference | (Inherited from Object) |
| ThresholdClass |
This API supports the Mono for Android infrastructure and is not intended to be used directly from your code. |
| ThresholdType |
This API supports the Mono for Android infrastructure and is not intended to be used directly from your code. |
Methods
| Cancel() |
Terminates this timer, discarding any currently scheduled tasks. |
| Clone() |
Creates and returns a copy of this object. (Inherited from Object) |
| Dispose() | (Inherited from Object) |
| Dispose(Boolean) | (Inherited from Object) |
| Equals(Object) |
Indicates whether some other object is "equal to" this one. (Inherited from Object) |
| GetHashCode() |
Returns a hash code value for the object. (Inherited from Object) |
| JavaFinalize() |
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. (Inherited from Object) |
| Notify() |
Wakes up a single thread that is waiting on this object's monitor. (Inherited from Object) |
| NotifyAll() |
Wakes up all threads that are waiting on this object's monitor. (Inherited from Object) |
| Purge() |
Removes all cancelled tasks from this timer's task queue. |
| Schedule(TimerTask, Date, Int64) |
Schedules the specified task for repeated fixed-delay execution, beginning at the specified time. |
| Schedule(TimerTask, Date) |
Schedules the specified task for execution at the specified time. |
| Schedule(TimerTask, Int64, Int64) |
Schedules the specified task for repeated fixed-delay execution, beginning after the specified delay. |
| Schedule(TimerTask, Int64) |
Schedules the specified task for execution after the specified delay. |
| ScheduleAtFixedRate(TimerTask, Date, Int64) |
Schedules the specified task for repeated fixed-rate execution, beginning at the specified time. |
| ScheduleAtFixedRate(TimerTask, Int64, Int64) |
Schedules the specified task for repeated fixed-rate execution, beginning after the specified delay. |
| SetHandle(IntPtr, JniHandleOwnership) |
Sets the Handle property. (Inherited from Object) |
| ToArray<T>() | (Inherited from Object) |
| ToString() |
Returns a string representation of the object. (Inherited from Object) |
| UnregisterFromRuntime() | (Inherited from Object) |
| Wait() |
Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>. (Inherited from Object) |
| Wait(Int64, Int32) |
Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>, or until a certain amount of real time has elapsed. (Inherited from Object) |
| Wait(Int64) |
Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>, or until a certain amount of real time has elapsed. (Inherited from Object) |
Explicit Interface Implementations
| IJavaPeerable.Disposed() | (Inherited from Object) |
| IJavaPeerable.DisposeUnlessReferenced() | (Inherited from Object) |
| IJavaPeerable.Finalized() | (Inherited from Object) |
| IJavaPeerable.JniManagedPeerState | (Inherited from Object) |
| IJavaPeerable.SetJniIdentityHashCode(Int32) | (Inherited from Object) |
| IJavaPeerable.SetJniManagedPeerState(JniManagedPeerStates) | (Inherited from Object) |
| IJavaPeerable.SetPeerReference(JniObjectReference) | (Inherited from Object) |
Extension Methods
| JavaCast<TResult>(IJavaObject) |
Performs an Android runtime-checked type conversion. |
| JavaCast<TResult>(IJavaObject) | |
| GetJniTypeName(IJavaPeerable) | |