With their violent histories established, we can take an even closer look within the precious metal atoms for more information about how they tick. General chemistry tells us two things: 1) that with a few exceptions, elements that appear in the same column (also called “groups”) tend to have similar properties, and 2) within an atom, it is the electrons that govern most of an element’s properties such as reflectiveness, propensity for oxidation, and color. Although all electrons of an atom are important for chemical properties, it Is the outer (valence) electrons that are the workhorses here. With that, the expression that denotes the distribution of electrons within the atom is known as the electron configuration.

Stop the timer, and cancel the execution of the timer’s action. This will only work if the timer is still in its waiting stage.

Return the thread stack size used when creating new threads. The optional size argument specifies the stack size to be used for subsequently created threads, and must be 0 (use platform or configured default) or a positive integer value of at least 32,768 (32 KiB). If size is not specified, 0 is used. If changing the thread stack size is unsupported, a RuntimeError is raised. If the specified stack size is invalid, a ValueError is raised and the stack size is unmodified. 32 KiB is currently the minimum supported stack size value to guarantee sufficient stack space for the interpreter itself. Note that some platforms may have particular restrictions on values for the stack size, such as requiring a minimum stack size > 32 KiB or requiring allocation in multiples of the system memory page size - platform documentation should be referred to for more information (4 KiB pages are common; using multiples of 4096 for the stack size is the suggested approach in the absence of more specific information).

This utility method may call wait() repeatedly until the predicate is satisfied, or until a timeout occurs. The return value is the last return value of the predicate and will evaluate to False if the method timed out.

Return a list of all Thread objects currently active. The list includes daemonic threads and dummy thread objects created by current_thread(). It excludes terminated threads and threads that have not yet been started. However, the main thread is always part of the result, even when terminated.

Class implementing event objects. An event manages a flag that can be set to true with the set() method and reset to false with the clear() method. The wait() method blocks until the flag is true. The flag is initially false.

It may be preferable to simply create the barrier with a sensible timeout value to automatically guard against one of the threads going awry.

Set a profile function for all threads started from the threading module and all Python threads that are currently executing.

Return the main Thread object. In normal conditions, the main thread is the thread from which the Python interpreter was started.

Set the internal flag to true. All threads waiting for it to become true are awakened. Threads that call wait() once the flag is true will not block at all.

The optional argument gives the initial value for the internal counter; it defaults to 1. If the value given is less than 0, ValueError is raised.

With this, one may wonder how odd-numbered nuclei come about (including silver and gold with atomic numbers of 47 and 79, respectively). The most straightforward solution comes in the form of a nuclear process called neutron capture.

Javathreadexample

As with any other chemical element, the precious metals were born billions of years ago when our galaxy began to take shape with the Big Bang. Element nuclei are synthesized in the center of stars at temperatures of millions of degrees and a level of pressure that makes forming diamonds in laboratories sound like a cakewalk; a process known as stellar nucleosynthesis. Atoms of hydrogen and helium, the simplest two elements by atomic number and what comprises 99% of the universe, are fused to build bigger nuclei of increasing atomic number.

When the underlying lock is an RLock, it is not released using its release() method, since this may not actually unlock the lock when it was acquired multiple times recursively. Instead, an internal interface of the RLock class is used, which really unlocks it even when it has been recursively acquired several times. Another internal interface is then used to restore the recursion level when the lock is reacquired.

The maximum value allowed for the timeout parameter of blocking functions (Lock.acquire(), RLock.acquire(), Condition.wait(), etc.). Specifying a timeout greater than this value will raise an OverflowError.

When invoked with the blocking argument set to True (the default), block until the lock is unlocked, then set it to locked and return True.

Gold, silver, and platinum. The big three of the precious metals realm. They are rare, beautiful, expensive, and typically smaller-sized specimens are represented in most collections. Most collectors are only able to be awestruck and take pictures of such large cabinet pieces that high-end collectors can possess.

When invoked with blocking set to False, do not block. If a call without an argument would block, return False immediately; otherwise, do the same thing as when called without arguments, and return True.

A primitive lock is in one of two states, “locked” or “unlocked”. It is created in the unlocked state. It has two basic methods, acquire() and release(). When the state is unlocked, acquire() changes the state to locked and returns immediately. When the state is locked, acquire() blocks until a call to release() in another thread changes it to unlocked, then the acquire() call resets it to locked and returns. The release() method should only be called in the locked state; it changes the state to unlocked and returns immediately. If an attempt is made to release an unlocked lock, a RuntimeError will be raised.

There is a “main thread” object; this corresponds to the initial thread of control in the Python program. It is not a daemon thread.

This class provides a simple synchronization primitive for use by a fixed number of threads that need to wait for each other. Each of the threads tries to pass the barrier by calling the wait() method and will block until all of the threads have made their wait() calls. At this point, the threads are released simultaneously.

Wait until notified or until a timeout occurs. If the calling thread has not acquired the lock when this method is called, a RuntimeError is raised.

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The German physicist, Arnold Sommerfeld (1868-1951), deduced that an electron’s speed could be found by the equation v = Zc / 137 (where c is the speed of light also used in Einstein’s most famous formula E = mc2, and Z is the atomic number of the atom considered). In the case of a gold electron (where Z = 79, the highest atomic numbered considered here), it moves at around 58% the speed of light. This is considerable enough for relativistic effects to be significant; in gold’s case, it is an “abnormal” color.

Changed in version 3.2: Lock acquisition can now be interrupted by signals on POSIX if the underlying threading implementation supports it.

The typical programming style using condition variables uses the lock to synchronize access to some shared state; threads that are interested in a particular change of state call wait() repeatedly until they see the desired state, while threads that modify the state call notify() or notify_all() when they change the state in such a way that it could possibly be a desired state for one of the waiters. For example, the following code is a generic producer-consumer situation with unlimited buffer capacity:

A thread can be flagged as a “daemon thread”. The significance of this flag is that the entire Python program exits when only daemon threads are left. The initial value is inherited from the creating thread. The flag can be set through the daemon property or the daemon constructor argument.

When the timeout argument is present and not None, it should be a floating-point number specifying a timeout for the operation in seconds, or fractions thereof.

Without the contraction, the energy required for the same jump would be in the ultraviolet (non-visible) range. With the 6s valence electron now being “protected”, only the most reactive substances on Earth can yank it out. Hence, the electron shielding is attributed to gold’s non-reactiveness or inert state. When King Tut’s sarcophagus was unearthed nearly a century ago, the gold comprising it still had its shimmering brilliance from when it was first crafted many millennia ago.

Release a lock, decrementing the recursion level. If after the decrement it is zero, reset the lock to unlocked (not owned by any thread), and if any other threads are blocked waiting for the lock to become unlocked, allow exactly one of them to proceed. If after the decrement the recursion level is still nonzero, the lock remains locked and owned by the calling thread.

A primitive lock is a synchronization primitive that is not owned by a particular thread when locked. In Python, it is currently the lowest level synchronization primitive available, implemented directly by the _thread extension module.

Semaphores are often used to guard resources with limited capacity, for example, a database server. In any situation where the size of the resource is fixed, you should use a bounded semaphore. Before spawning any worker threads, your main thread would initialize the semaphore:

Note that using this function may require some external synchronization if there are other threads whose state is unknown. If a barrier is broken it may be better to just leave it and create a new one.

Other threads can call a thread’s join() method. This blocks the calling thread until the thread whose join() method is called is terminated.

Release the underlying lock. This method calls the corresponding method on the underlying lock; there is no return value.

The ‘thread identifier’ of this thread or None if the thread has not been started. This is a nonzero integer. See the get_ident() function. Thread identifiers may be recycled when a thread exits and another thread is created. The identifier is available even after the thread has exited.

asyncio offers an alternative approach to achieving task level concurrency without requiring the use of multiple operating system threads.

This class implements semaphore objects. A semaphore manages an atomic counter representing the number of release() calls minus the number of acquire() calls, plus an initial value. The acquire() method blocks if necessary until it can return without making the counter negative. If not given, value defaults to 1.

Note that RLock is actually a factory function which returns an instance of the most efficient version of the concrete RLock class that is supported by the platform.

Set a profile function for all threads started from the threading module. The func will be passed to sys.setprofile() for each thread, before its run() method is called.

In reviewing the fact that gold and silver have similar properties, by being in the same column or family, it is easy to spot that copper is in the same boat. However, in the precious metal realm, it is often snubbed due to its relatively common occurrence and of course, low cost. I often tend to think of copper as precious in terms of its contribution to early human civilizations with the Bronze Age. For the above two reasons, I will include the red metal here.

Set a trace function for all threads started from the threading module and all Python threads that are currently executing.

As more and more neutrons are added to a single nucleus, it eventually becomes unstable and undergoes another nuclear process known as beta decay. It is important to note that it is the protons that dictate an atom’s elemental identity, not the neutrons (the former serves as an atomic fingerprint of sorts.

Create a timer that will run function with arguments args and keyword arguments kwargs, after interval seconds have passed. If args is None (the default) then an empty list will be used. If kwargs is None (the default) then an empty dict will be used.

Acquire the underlying lock. This method calls the corresponding method on the underlying lock; the return value is whatever that method returns.

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Therefore, the same rules apply as with wait(): The lock must be held when called and is re-acquired on return. The predicate is evaluated with the lock held.

The electrons absorb the energy that allows them to “jump” to higher energy levels. When said electrons return to their original energy level, they release a quantity of energy in the form of certain wavelengths associated with certain colors.

If the internal counter is zero on entry, block until awoken by a call to release(). Once awoken (and the counter is greater than 0), decrement the counter by 1 and return True. Exactly one thread will be awoken by each call to release(). The order in which threads are awoken should not be relied on.

Once the thread’s activity is started, the thread is considered ‘alive’. It stops being alive when its run() method terminates – either normally, or by raising an unhandled exception. The is_alive() method tests whether the thread is alive.

Javathread

A reentrant lock is a synchronization primitive that may be acquired multiple times by the same thread. Internally, it uses the concepts of “owning thread” and “recursion level” in addition to the locked/unlocked state used by primitive locks. In the locked state, some thread owns the lock; in the unlocked state, no thread owns it.

acquire()/release() must be used in pairs: each acquire must have a release in the thread that has acquired the lock. Failing to call release as many times the lock has been acquired can lead to deadlock.

The Thread ID (TID) of this thread, as assigned by the OS (kernel). This is a non-negative integer, or None if the thread has not been started. See the get_native_id() function. This value may be used to uniquely identify this particular thread system-wide (until the thread terminates, after which the value may be recycled by the OS).

The PGE preference for all things mafic comes from their proximity to iron on the Periodic Table, a dominant element in mafic rocks such as basalt, gabbro, and peridotite. Given this “one-dimensionality” of platinum, nearly all well-formed specimens are cubes that have formed under a restricted temperature and depth range.

These cement and resin coated specialty nails are specifically designed with a small diameter to reduce splitting and cracking during assembly.

A condition variable obeys the context management protocol: using the with statement acquires the associated lock for the duration of the enclosed block. The acquire() and release() methods also call the corresponding methods of the associated lock.

Return the current Thread object, corresponding to the caller’s thread of control. If the caller’s thread of control was not created through the threading module, a dummy thread object with limited functionality is returned.

CPython implementation detail: In CPython, due to the Global Interpreter Lock, only one thread can execute Python code at once (even though certain performance-oriented libraries might overcome this limitation). If you want your application to make better use of the computational resources of multi-core machines, you are advised to use multiprocessing or concurrent.futures.ProcessPoolExecutor. However, threading is still an appropriate model if you want to run multiple I/O-bound tasks simultaneously.

When invoked with the floating-point timeout argument set to a positive value, block for at most the number of seconds specified by timeout and as long as the lock cannot be acquired. A timeout argument of -1 specifies an unbounded wait. It is forbidden to specify a timeout when blocking is False.

When the timeout argument is present and not None, it should be a floating-point number specifying a timeout for the operation in seconds (or fractions thereof). As join() always returns None, you must call is_alive() after join() to decide whether a timeout happened – if the thread is still alive, the join() call timed out.

In comparing silver to platinum, the latter experiences the same shielding effect as gold, also giving rise to platinum’s tarnish resistance. The same cannot be said for silver since it lacks the “f” electron orbitals to provide the shielding effect and is attacked over time by the likes of oxygen and sulfur. Despite this, silver is still considered a “noble metal” that takes some time to degrade. If one were to peek at a tool called the activity series, the precious metals are neatly gathered at the bottom of this “totem pole.” With this pole, however, being at the bottom is great. It signifies an unwillingness to give up electrons in reactions, which leads to oxidation. At least silver is nowhere near as bad as iron.

If an action was provided to the constructor, one of the threads will have called it prior to being released. Should this call raise an error, the barrier is put into the broken state.

Set a trace function for all threads started from the threading module. The func will be passed to sys.settrace() for each thread, before its run() method is called.

When it comes to the crystal forms of platinum, and the rest of the PGEs, it is a slightly different story. Although they also crystallize in the cubic system, they chiefly form in a more specialized environment. Whereas the other three metals can be found in a host of geological systems and host rocks, the PGEs preferably are found in mafic igneous rocks, with the clear majority of said rocks being part of layered mafic intrusions (LMIs) emplaced in shallow levels of the crust. The number of native copper, silver, and gold locales is far too numerous to list, but those of platinum can be displayed here (list).

During a supernova explosion, a massive quantity of neutrons from the star’s core are shot out (like pellets from a buckshot shotgun shell) and incorporate themselves into the newly-formed heavier nuclei also shot out.

Return the barrier to the default, empty state. Any threads waiting on it will receive the BrokenBarrierError exception.

name is the thread name. By default, a unique name is constructed of the form “Thread-N” where N is a small decimal number, or “Thread-N (target)” where “target” is target.__name__ if the target argument is specified.

There is the possibility that “dummy thread objects” are created. These are thread objects corresponding to “alien threads”, which are threads of control started outside the threading module, such as directly from C code. Dummy thread objects have limited functionality; they are always considered alive and daemonic, and cannot be joined. They are never deleted, since it is impossible to detect the termination of alien threads.

These elements are concentrated mainly in the upper mantle, which can then be brought to mineable levels via tectonic uplifting, magmatic, and hydrothermal fluid activity. With this, the only reason that we can access gold and the platinum group elements (PGEs) is due to an astronomical stroke of luck. It is thought that around four billion years ago, a swarm of meteorites impacted the Earth in an event known as the Late Heavy Bombardment.

Thread-local data is data whose values are thread specific. To manage thread-local data, just create an instance of local (or a subclass) and store attributes on it:

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Whether it is for investment purposes or having something akin to owning a Rembrandt or Picasso, it is no secret that precious metals are highly sought after. Despite their beauty and high value, it seems like the true scientific value of the precious metals tends to be overlooked. With that, we shall dive into the true origins of these prized metals, and how their placement on the Periodic Table not only makes them precious, but rather unusual!

Note: an awakened thread does not actually return from its wait() call until it can reacquire the lock. Since notify() does not release the lock, its caller should.

A semaphore manages an internal counter which is decremented by each acquire() call and incremented by each release() call. The counter can never go below zero; when acquire() finds that it is zero, it blocks, waiting until some other thread calls release().

For more details and extensive examples, see the documentation string of the _threading_local module: Lib/_threading_local.py.

For anyone that has collected specimens of gold, copper, and silver, one has got to be struck by the myriad of wondrous crystal forms such as cubes, dendritic, wires, octahedral, sheet, herringbone, and spinel law twin to name several. Although all three crystallize in the cubic class, the various crystal forms of any mineral are a direct reflection of the environment they grew in; more specifically with pressure, temperature, pH of the crystallization medium, as well as salinity (i.e. other minerals dissolved with the precious metals). It is no coincidence that gold, silver, and copper display the same forms by being in the same family.

This is one of the simplest mechanisms for communication between threads: one thread signals an event and other threads wait for it.

The Thread class represents an activity that is run in a separate thread of control. There are two ways to specify the activity: by passing a callable object to the constructor, or by overriding the run() method in a subclass. No other methods (except for the constructor) should be overridden in a subclass. In other words, only override the __init__() and run() methods of this class.

Java newThread

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This method wakes up at most n of the threads waiting for the condition variable; it is a no-op if no threads are waiting.

Given the extremes required for their formation, their quantum eccentricities, and some “astronomical” luck, hopefully, after reading this you will have gained a much deeper appreciation for the Picassos of the native metal realm no matter what level collector you are, and no matter the size of such specimens in your collection.

Changed in version 3.13: Lock is now a class. In earlier Pythons, Lock was a factory function which returned an instance of the underlying private lock type.

Storing thread using a custom hook can resurrect it if it is set to an object which is being finalized. Avoid storing thread after the custom hook completes to avoid resurrecting objects.

If called multiple times, failing to call release() as many times may lead to deadlock. Consider using RLock as a context manager rather than calling acquire/release directly.

If not None, daemon explicitly sets whether the thread is daemonic. If None (the default), the daemonic property is inherited from the current thread.

When this happens, an additional influx of outside energy will not increase the speed even more but rather add on to the atom’s mass in a phenomenon known as relativistic mass. In theory, all objects have relativistic mass, but mere mortals cannot detect it because we, and most other objects, move at such a “slow” speed. Thus, it is negligible.

If the same thread owns the lock, acquire the lock again, and return immediately. This is the difference between Lock and RLock; Lock handles this case the same as the previous, blocking until the lock can be acquired.

To choose between notify() and notify_all(), consider whether one state change can be interesting for only one or several waiting threads. E.g. in a typical producer-consumer situation, adding one item to the buffer only needs to wake up one consumer thread.

It must be called at most once per thread object. It arranges for the object’s run() method to be invoked in a separate thread of control.

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A string used for identification purposes only. It has no semantics. Multiple threads may be given the same name. The initial name is set by the constructor.

This method returns True just before the run() method starts until just after the run() method terminates. The module function enumerate() returns a list of all alive threads.

A condition variable is always associated with some kind of lock; this can be passed in or one will be created by default. Passing one in is useful when several condition variables must share the same lock. The lock is part of the condition object: you don’t have to track it separately.

In the case of gold, it is the blue wavelengths that are absorbed with the complimentary yellow hues being reflected. If only that explanation were that simple! Along with jumping electrons, we can contribute gold’s “odd” color to quantum mechanics and Einstein! Along with Erwin Schrodinger in the mid-1920s, Einstein helped develop the more contemporary and accurate model of the atom, which is known as the quantum-mechanical model.

Similar to Process IDs, Thread IDs are only valid (guaranteed unique system-wide) from the time the thread is created until the thread has been terminated.

Put the barrier into a broken state. This causes any active or future calls to wait() to fail with the BrokenBarrierError. Use this for example if one of the threads needs to abort, to avoid deadlocking the application.

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This class implements reentrant lock objects. A reentrant lock must be released by the thread that acquired it. Once a thread has acquired a reentrant lock, the same thread may acquire it again without blocking; the thread must release it once for each time it has acquired it.

Once a thread object is created, its activity must be started by calling the thread’s start() method. This invokes the run() method in a separate thread of control.

If the lock argument is given and not None, it must be a Lock or RLock object, and it is used as the underlying lock. Otherwise, a new RLock object is created and used as the underlying lock.

The design of this module is loosely based on Java’s threading model. However, where Java makes locks and condition variables basic behavior of every object, they are separate objects in Python. Python’s Thread class supports a subset of the behavior of Java’s Thread class; currently, there are no priorities, no thread groups, and threads cannot be destroyed, stopped, suspended, resumed, or interrupted. The static methods of Java’s Thread class, when implemented, are mapped to module-level functions.

The current implementation wakes up exactly n threads, if at least n threads are waiting. However, it’s not safe to rely on this behavior. A future, optimized implementation may occasionally wake up more than n threads.

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with positional and keyword arguments taken from the args and kwargs arguments, respectively.

Accompanying most heavier nuclei is a concept called relativistic effects, which was also envisioned by Einstein. It should also be noted that the following explanation of how these effects affect precious metals is very simplified.

For both of those metals, they are only one electron away from having a full “d” shell. Additionally, electrons love to work in pairs, and atoms seem to prefer orbitals that are either full, half-full, or empty. What happens with silver and gold is that one electron from the “s” orbital is transferred to the “d” orbital, to make it full and leave the “s” orbital half full. Thus, the respective true electron configurations are [Kr]5s14d10, whereas gold’s configuration is [Xe]6s14f145d10. It is the movement of the one lone “s” electron that gives rise to the highly illustrious nature and very high electrical conductivities. Silver is the most reflective element, reflecting 99% of the light that hits it, whereas gold reflects around 95%. Oftentimes, high shimmer and preciousness go together, and we have a single electron with nearly no mass to thank!

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join() raises a RuntimeError if an attempt is made to join the current thread as that would cause a deadlock. It is also an error to join() a thread before it has been started and attempts to do so raise the same exception.

Netty virtual threads

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thought to be a very hot homogeneous mixture that has separated into density-stratified layers (much like what oil and water do). Elements such as iron, manganese, cobalt, nickel, molybdenum, gold and the platinum group (e.g. Pt, Pd, Ru, Rh, Re, Ir, and Os) are called siderophile (iron-loving) elements, in which they have sunk into the core, out of our mineable reach.

All electrons zip around the outside of atoms, within orbitals, at extremely high speeds. Typically, an infusion of energy, such as heat, light, or electricity, will increase an electron’s movement or kinetic energy. In some of the heaviest nuclei, electrons travel at speeds comparable to that of light. Think of this as moving planetary bodies. Bigger bodies (heavier nuclei) possess a stronger gravity, which makes objects near it (electrons) move faster.

Reset the internal flag to false. Subsequently, threads calling wait() will block until set() is called to set the internal flag to true again.

To the chemistry tyro, the configuration for silver is seemingly [Kr]5s24d9, whereas gold’s configuration appears to be [Xe]6s24f145d9. The larger numbers (called coefficients) indicate electron energy levels or relative distance from the nucleus. The letters indicate the geometric-shaped “cloud” (or orbitals) where the electrons probably reside (they are always on the move). The smaller numbers (or superscripts) are the number of electrons (in a neutral atom, the superscripts add up to the atomic number). As you can see in silver and gold, they both have 9 “d” electrons (a “d” shell can hold a maximum of 10 electrons, just count the number of Periodic Table squares across any complete row of transition elements), and it is in the d shell where some interesting phenomena takes place!

java new thread使用

Return the ‘thread identifier’ of the current thread. This is a nonzero integer. Its value has no direct meaning; it is intended as a magic cookie to be used e.g. to index a dictionary of thread-specific data. Thread identifiers may be recycled when a thread exits and another thread is created.

An event object manages an internal flag that can be set to true with the set() method and reset to false with the clear() method. The wait() method blocks until the flag is true.

This method releases the underlying lock, and then blocks until it is awakened by a notify() or notify_all() call for the same condition variable in another thread, or until the optional timeout occurs. Once awakened or timed out, it re-acquires the lock and returns.

Reentrant locks support the context management protocol, so it is recommended to use with instead of manually calling acquire() and release() to handle acquiring and releasing the lock for a block of code.

It is no secret that the luster and color of gold have made it the metal of envy for millennia, but what exactly is it that gives gold that famous yellow hue? Introductory chemistry students are often introduced to a two-dimensional Bohr Model of the atom to explain not only the number of valence electrons an element has but also how electrons jump from “ring to ring”, or between energy levels when they absorb energy. Visible, or white, light contains a fixed range of energy as denoted by the electromagnetic spectrum.

Wake up all threads waiting on this condition. This method acts like notify(), but wakes up all waiting threads instead of one. If the calling thread has not acquired the lock when this method is called, a RuntimeError is raised.

With beta decay, a neutron turns into a proton and electron, and it’s this mechanism that adds one proton to the nucleus. Hence the atomic number goes up by only one to give the odd-numbered elements. Additionally, odd-numbered elements can also be achieved by trace amounts of unfused, “residual” hydrogen atoms being fused with any of the heavier nuclei as well.

When more than one thread is blocked in acquire() waiting for the state to turn to unlocked, only one thread proceeds when a release() call resets the state to unlocked; which one of the waiting threads proceeds is not defined, and may vary across implementations.

Wait until a condition evaluates to true. predicate should be a callable which result will be interpreted as a boolean value. A timeout may be provided giving the maximum time to wait.

This class represents an action that should be run only after a certain amount of time has passed — a timer. Timer is a subclass of Thread and as such also functions as an example of creating custom threads.

Create a barrier object for parties number of threads. An action, when provided, is a callable to be called by one of the threads when they are released. timeout is the default timeout value if none is specified for the wait() method.

This class implements condition variable objects. A condition variable allows one or more threads to wait until they are notified by another thread.

Currently, Lock, RLock, Condition, Semaphore, and BoundedSemaphore objects may be used as with statement context managers.

A boolean value indicating whether this thread is a daemon thread (True) or not (False). This must be set before start() is called, otherwise RuntimeError is raised. Its initial value is inherited from the creating thread; the main thread is not a daemon thread and therefore all threads created in the main thread default to daemon = False.

Note: the notify() and notify_all() methods don’t release the lock; this means that the thread or threads awakened will not return from their wait() call immediately, but only when the thread that called notify() or notify_all() finally relinquishes ownership of the lock.

Pass the barrier. When all the threads party to the barrier have called this function, they are all released simultaneously. If a timeout is provided, it is used in preference to any that was supplied to the class constructor.

In all cases, if the thread was able to acquire the lock, return True. If the thread was unable to acquire the lock (i.e. if not blocking or the timeout was reached) return False.

If the run() method raises an exception, threading.excepthook() is called to handle it. By default, threading.excepthook() ignores silently SystemExit.

When invoked with a timeout other than None, it will block for at most timeout seconds. If acquire does not complete successfully in that interval, return False. Return True otherwise.

The theory is the most likely explanation of how we can get mineable quantities of precious siderophile elements at crustal levels. A modern-day connection to this is the observation of a $5.4 trillion meteorite containing approximately 90 million tons of platinum passing near Earth in the summer of 2015 (and prompting the attention of prospective “space miners”). The platinum is alloyed with iron and nickel, all being chalcophile elements. Imagine how society might be different if the bombardment did not happen, and silver ended up being the chief of all precious metals rather than playing second fiddle!

Class implementing bounded semaphore objects. A bounded semaphore checks to make sure its current value doesn’t exceed its initial value. If it does, ValueError is raised. In most situations semaphores are used to guard resources with limited capacity. If the semaphore is released too many times it’s a sign of a bug. If not given, value defaults to 1.

The use of a bounded semaphore reduces the chance that a programming error which causes the semaphore to be released more than it’s acquired will go undetected.

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By default, wake up one thread waiting on this condition, if any. If the calling thread has not acquired the lock when this method is called, a RuntimeError is raised.

During a supernova event, the star’s core collapses on itself then explodes, expelling all its created elements out into space. The core collapse event takes place in fractions of a second, and for that time, the sharp temperature and pressure increases are sufficient to fuse the heavier nuclei before expulsion. If we take a quick look at the Periodic Table, with most of the elements below atomic number 26, we can relate them to how common they are on and above the Earth’s surface. It is no coincidence that the eight most common elements in the Earth’s crust (O, Si, Al, Fe, Mg, Na, K, Ca) fit this pattern. Needless to say, the greatest amount of hell was raised to give birth to the precious metal beauties!

When the timeout argument is present and not None, it should be a floating-point number specifying a timeout for the operation in seconds (or fractions thereof).

Another intriguing pattern seen in the elements is the fact that those with an even atomic number are generally more abundant in the universe, this being known as the Oddo-Harkins Effect. This can also be explained with stellar nucleosynthesis and, once again, with hydrogen and helium. The typical progression that happens in stars is that two hydrogen atoms (with one proton each) fuse to form helium, then two helium atoms bond to form beryllium, with the process keeping on forming nuclei with even-numbered protons every time.

The notify() method wakes up one of the threads waiting for the condition variable, if any are waiting. The notify_all() method wakes up all threads waiting for the condition variable.

In this case, silver has fared a little better being classified as a chalcophile (copper-loving) element, along with the likes of sulfur, lead, zinc, and tin, to name a few.

This process within stars continues until the iron is synthesized (atomic number 26), wherein iron nuclei are so tightly bound that fusion cannot continue at existing temperatures and pressures. Secondly, the fusion of iron atoms does not produce additional energy, as a byproduct, as lighter elements do. Without a continuous energy (or fuel) source, a star’s days become numbered where a supernova will soon follow.

The return value is an integer in the range 0 to parties – 1, different for each thread. This can be used to select a thread to do some special housekeeping, e.g.:

When the lock is locked, reset it to unlocked, and return. If any other threads are blocked waiting for the lock to become unlocked, allow exactly one of them to proceed.

Copper’s electron configuration is [Ar] 4s13d10 and possesses nearly the same relativistic effects as gold but on a slightly smaller scale. Since copper is a smaller atom than gold (it possesses less filled energy levels), the electron jumps between the 4s and the 3d levels do not require as much energy. This is manifested as a lower energy red-orange wavelength being released versus the slightly higher energy orange-yellow wavelengths of gold thanks to its additional energy levels. Lastly, copper is the most prone to oxidation since it experiences the least amount of electron shielding, with relativistic contraction, simply due to its least number of electrons and energy levels (hence its higher status on the activity series). Although it is by far the most common metal considered here, it is priceless in terms of advancing early civilizations. Think of how behind we could be today if someone wasn’t intrigued by copper’s redness.

concurrent.futures.ThreadPoolExecutor offers a higher level interface to push tasks to a background thread without blocking execution of the calling thread, while still being able to retrieve their results when needed.

Thread startrun

It should be noted that relativistic effects are an overarching, collective term indicative of different effects on different elements. Perhaps it is no coincidence that gold and mercury are right beside each other on the Periodic Table and compared to normal metals that both are “oddballs” due to relativity, with mercury’s effects being that it’s liquid. Relativistic effects have a second and very important effect on gold, without which we may never view gold with the same value despite its color. Due to its very full “d” electron orbital, housing fourteen electrons (and all at very high speeds, no less), it pulls in or contracts the one lonely 6s closer to the nucleus and shields it from being transferred (or bonded to another element) in a reaction. This contraction allows an electron to jump from the 5d to the 6s level at energy equating to the release of a yellow wavelength.

All of the objects provided by this module that have acquire and release methods can be used as context managers for a with statement. The acquire method will be called when the block is entered, and release will be called when the block is exited. Hence, the following snippet:

threadrun start区别

If the subclass overrides the constructor, it must make sure to invoke the base class constructor (Thread.__init__()) before doing anything else to the thread.

Block as long as the internal flag is false and the timeout, if given, has not expired. The return value represents the reason that this blocking method returned; True if returning because the internal flag is set to true, or False if a timeout is given and the internal flag did not become true within the given wait time.

Only call this method when the calling thread owns the lock. A RuntimeError is raised if this method is called when the lock is not acquired.

This is one of the oldest synchronization primitives in the history of computer science, invented by the early Dutch computer scientist Edsger W. Dijkstra (he used the names P() and V() instead of acquire() and release()).

Holds the original value of threading.excepthook(). It is saved so that the original value can be restored in case they happen to get replaced with broken or alternative objects.

In the Python 2.x series, this module contained camelCase names for some methods and functions. These are deprecated as of Python 3.10, but they are still supported for compatibility with Python 2.5 and lower.

Timers are started, as with threads, by calling their Timer.start method. The timer can be stopped (before its action has begun) by calling the cancel() method. The interval the timer will wait before executing its action may not be exactly the same as the interval specified by the user.

Other methods must be called with the associated lock held. The wait() method releases the lock, and then blocks until another thread awakens it by calling notify() or notify_all(). Once awakened, wait() re-acquires the lock and returns. It is also possible to specify a timeout.

Java virtualthreadexample

One of the primary differences between the two models is how the areas where electrons live are described. Electrons technically live in geometrical “clouds” of probability called orbitals. Like with the Bohr model, orbitals exist in increasing sizes or energy levels away from the nucleus.

The class implementing primitive lock objects. Once a thread has acquired a lock, subsequent attempts to acquire it block, until it is released; any thread may release it.

The while loop checking for the application’s condition is necessary because wait() can return after an arbitrary long time, and the condition which prompted the notify() call may no longer hold true. This is inherent to multi-threaded programming. The wait_for() method can be used to automate the condition checking, and eases the computation of timeouts:

Return the number of Thread objects currently alive. The returned count is equal to the length of the list returned by enumerate().

Daemon threads are abruptly stopped at shutdown. Their resources (such as open files, database transactions, etc.) may not be released properly. If you want your threads to stop gracefully, make them non-daemonic and use a suitable signalling mechanism such as an Event.

Wait until the thread terminates. This blocks the calling thread until the thread whose join() method is called terminates – either normally or through an unhandled exception – or until the optional timeout occurs.

Storing exc_value using a custom hook can create a reference cycle. It should be cleared explicitly to break the reference cycle when the exception is no longer needed.

Release a semaphore, incrementing the internal counter by n. When it was zero on entry and other threads are waiting for it to become larger than zero again, wake up n of those threads.

RLock’s acquire()/release() call pairs may be nested, unlike Lock’s acquire()/release(). Only the final release() (the release() of the outermost pair) resets the lock to an unlocked state and allows another thread blocked in acquire() to proceed.

Return the native integral Thread ID of the current thread assigned by the kernel. This is a non-negative integer. Its value may be used to uniquely identify this particular thread system-wide (until the thread terminates, after which the value may be recycled by the OS).

When invoked with the blocking argument set to False, do not block. If a call with blocking set to True would block, return False immediately; otherwise, set the lock to locked and return True.