runWithScissors

http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.2.2_r1/android/os/Handler.java

Runs the specified task synchronously. If the current thread is the same as the handler thread, then the runnable runs immediately without being enqueued. Otherwise, posts the runnable to the handler and waits for it to complete before returning. This method is dangerous! Improper use can result in deadlocks. Never call this method while any locks are held or use it in a possibly re-entrant manner. This method is occasionally useful in situations where a background thread must synchronously await completion of a task that must run on the handler's thread. However, this problem is often a symptom of bad design. Consider improving the design (if possible) before resorting to this method. One example of where you might want to use this method is when you just set up a Handler thread and need to perform some initialization steps on it before continuing execution. If timeout occurs then this method returnsfalse but the runnable will remain posted on the handler and may already be in progress or complete at a later time.

Parameters:

r The Runnable that will be executed synchronously.

timeout The timeout in milliseconds, or 0 to wait indefinitely.

Returns:

Returns true if the Runnable was successfully executed. Returns false on failure, usually because the looper processing the message queue is exiting.

Hide:

This method is prone to abuse and should probably not be in the API. If we ever do make it part of the API, we might want to rename it to something less funny like runUnsafe().

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    public final boolean runWithScissors(final Runnable r, long timeout) {

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        if (r == null) {

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            throw new IllegalArgumentException("runnable must not be null");

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        }

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        if (timeout < 0) {

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            throw new IllegalArgumentException("timeout must be non-negative");

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        }

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        if (Looper.myLooper() == mLooper) {

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            r.run();

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            return true;

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        }

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        BlockingRunnable br = new BlockingRunnable(r);

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        return br.postAndWait(this, timeout);

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    }