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The object pool pattern is a software creational design pattern that uses a set of initialized objects kept ready to use – a "pool" – rather than allocating and destroying them on demand. A client of the pool will request an object from the pool and perform operations on the returned object.
A design pattern is the re-usable form of a solution to a design problem. The idea was introduced by the architect Christopher Alexander [ 1 ] and has been adapted for various other disciplines, particularly software engineering .
In software engineering, the composite pattern is a partitioning design pattern. The composite pattern describes a group of objects that are treated the same way as a single instance of the same type of object. The intent of a composite is to "compose" objects into tree structures to represent part-whole hierarchies.
The basic idea is to have a class for each symbol (terminal or nonterminal) in a specialized computer language. The syntax tree of a sentence in the language is an instance of the composite pattern and is used to evaluate (interpret) the sentence for a client. [1]: 243 See also Composite pattern.
Rather than having a single instance per application (e.g. the java.lang.Runtime object in the Java programming language) the multiton pattern instead ensures a single instance per key. The multiton pattern does not explicitly appear as a pattern in the highly regarded object-oriented programming textbook Design Patterns. [1]
The following example is in the language Java, and shows how the contents of a tree of nodes (in this case describing the components of a car) can be printed. Instead of creating print methods for each node subclass ( Wheel , Engine , Body , and Car ), one visitor class ( CarElementPrintVisitor ) performs the required printing action.
Example of a binary max-heap with node keys being integers between 1 and 100. In computer science, a heap is a tree-based data structure that satisfies the heap property: In a max heap, for any given node C, if P is the parent node of C, then the key (the value) of P is greater than or equal to the key of C.
A pattern language is an organized and coherent set of patterns, ... At this point, the design almost always becomes a better design. In the language, therefore, each ...