PhutilArrayWithDefaultValue.php
7df0fc1297f9stable

PhutilArrayWithDefaultValue.php
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			<?php

			/**
			* Array-like object with a default value that is populated when nonexistent
			* keys are accessed. This is particularly useful to avoid constructs like this:
			*
			* $counts = array();
			* foreach ($fruit as $fruit) {
			* if (!isset($counts[$fruit])) {
			* $counts[$fruit] = 0;
			* }
			* $counts[$fruit] += 1;
			* }
			*
			* Instead, you can use PhutilArrayWithDefaultValue:
			*
			* $counts = new PhutilArrayWithDefaultValue();
			* foreach ($fruits as $fruit) {
			* $counts[$fruit] += 1;
			* }
			*
			* NOTE: You must use the `+= 1` operator, not `++`, because PHP is the crown
			* jewel of programming languages.
			*
			* Normally, the default value is `0` to allow the object to be used to count
			* things or build bitmasks. You can change the default with
			* @{method:setDefaultValue}.
			*/
			final class PhutilArrayWithDefaultValue extends PhutilArray {

			private $defaultValue = 0;

			public function setDefaultValue($default_value) {
			$this->defaultValue = $default_value;
			return $this;
			}

			public function offsetExists($key) {
			return true;
			}

			public function offsetGet($key) {
			if (!parent::offsetExists($key)) {
			$this->offsetSet($key, $this->defaultValue);
			}
			return parent::offsetGet($key);
			}

			}