Search results
Results From The WOW.Com Content Network
For unordered access as defined in the java.util.Map interface, the java.util.concurrent.ConcurrentHashMap implements java.util.concurrent.ConcurrentMap. [2] The mechanism is a hash access to a hash table with lists of entries, each entry holding a key, a value, the hash, and a next reference.
Threading Building Blocks provide concurrent unordered maps for C++ which allow concurrent insertion and traversal and are kept in a similar style to the C++11 std::unordered_map interface. Included within are the concurrent unordered multimaps, which allow multiple values to exist for the same key in a concurrent unordered map. [ 12 ]
The hash function in Java, used by HashMap and HashSet, is provided by the Object.hashCode() method. Since every class in Java inherits from Object , every object has a hash function. A class can override the default implementation of hashCode() to provide a custom hash function more in accordance with the properties of the object.
Such languages provide synchronization constructs whose behavior is defined by a parallel execution model. A concurrent programming language is defined as one which uses the concept of simultaneously executing processes or threads of execution as a means of structuring a program.
Collection implementations in pre-JDK 1.2 versions of the Java platform included few data structure classes, but did not contain a collections framework. [4] The standard methods for grouping Java objects were via the array, the Vector, and the Hashtable classes, which unfortunately were not easy to extend, and did not implement a standard member interface.
This difficult-to-diagnose logic error, which may compile and run properly most of the time, is called a race condition. One common way to avoid this is to use another shared variable as a "lock" or "mutex" (from mutual exclusion). In the following piece of C code, the function is thread-safe, but not reentrant:
In computer science, compare-and-swap (CAS) is an atomic instruction used in multithreading to achieve synchronization.It compares the contents of a memory location with a given value and, only if they are the same, modifies the contents of that memory location to a new given value.
In computer science, read-copy-update (RCU) is a synchronization mechanism that avoids the use of lock primitives while multiple threads concurrently read and update elements that are linked through pointers and that belong to shared data structures (e.g., linked lists, trees, hash tables).