Your IP : 3.128.205.21
<?php
namespace RebelCode\Wpra\Core\Data;
use Exception;
use RebelCode\Wpra\Core\Util\MergedIterator;
/**
* An implementation of a data set that merged two data sets, with customizable override behavior and iteration.
*
* @since 4.13
*/
class MergedDataSet extends AbstractDataSet
{
/**
* Iteration mode for only iterating over the primary data set.
*
* @since 4.13
*/
const ITERATE_PRIMARY = 0;
/**
* Iteration mode for only iterating over the secondary data set.
*
* @since 4.13
*/
const ITERATE_SECONDARY = 1;
/**
* Iteration mode for iterating over both data sets, yielding only unique keys.
*
* @since 4.13
*/
const ITERATE_BOTH = 2;
/**
* The primary data set.
*
* @since 4.13
*
* @var DataSetInterface
*/
protected $primary;
/**
* The secondary data set.
*
* @since 4.13
*
* @var DataSetInterface
*/
protected $secondary;
/**
* The map of keys that the primary overrides.
*
* @since 4.13
*
* @var bool[]
*/
protected $overrideMap;
/**
* Description
*
* @since 4.13
*
* @var bool
*/
protected $iteration;
/**
* Constructor.
*
* @since 4.13
*
* @param DataSetInterface $primary The primary data set to use.
* @param DataSetInterface $secondary The secondary data set to use for keys that don't exist in the primary.
* @param bool[] $overrideMap The map of keys to booleans. If the primary data set has the key but the
* key exists in this map and is mapped to `true`, the secondary dataset will
* be used instead. If the key is not in the map or maps to `false`, the normal
* override behavior is used.
* @param int $iteration The iteration mode. See the `ITERATE_*` constants provided by this class.
*/
public function __construct(
DataSetInterface $primary,
DataSetInterface $secondary,
$overrideMap = [],
$iteration = self::ITERATE_BOTH
) {
$this->primary = $primary;
$this->secondary = $secondary;
$this->overrideMap = $overrideMap;
$this->iteration = $iteration;
}
/**
* {@inheritdoc}
*
* @since 4.13
*/
protected function has($key)
{
return $this->isOverridden($key)
? $this->secondary->offsetExists($key)
: $this->primary->offsetExists($key) || $this->secondary->offsetExists($key);
}
/**
* {@inheritdoc}
*
* @since 4.13
*/
protected function get($key)
{
return $this->primary->offsetExists($key) && !$this->isOverridden($key)
? $this->primary->offsetGet($key)
: $this->secondary->offsetGet($key);
}
/**
* {@inheritdoc}
*
* @since 4.13
*/
protected function set($key, $value)
{
if ($this->isOverridden($key)) {
$this->secondary->offsetSet($key, $value);
return;
}
try {
$this->primary->offsetSet($key, $value);
} catch (Exception $exception) {
$this->secondary->offsetSet($key, $value);
}
}
/**
* {@inheritdoc}
*
* @since 4.13
*/
protected function delete($key)
{
if ($this->isOverridden($key)) {
$this->secondary->offsetUnset($key);
return;
}
try {
$this->primary->offsetUnset($key);
} catch (Exception $exception) {
$this->secondary->offsetUnset($key);
}
}
/**
* Checks if a key is marked as being overridden.
*
* @since 4.13
*
* @param int|string $key The key.
*
* @return bool True if the key is overridden, false if not.
*/
protected function isOverridden($key)
{
return array_key_exists($key, $this->overrideMap) && $this->overrideMap[$key] !== false;
}
/**
* {@inheritdoc}
*
* @since 4.13
*/
protected function getIterator()
{
if ($this->iteration === static::ITERATE_PRIMARY) {
return $this->primary;
}
if ($this->iteration === static::ITERATE_SECONDARY) {
return $this->secondary;
}
return new MergedIterator([$this->primary, $this->secondary]);
}
/**
* {@inheritdoc}
*
* @since 4.13
*/
public function current()
{
$key = $this->_iterator->key();
$set = $this->getChildForKey($key);
$val = $set->offsetGet($key);
return $this->yieldIterationValue($val);
}
/**
* Retrieves the child dataset to use for a given key.
*
* This method will attempt to return the dataset that already has the key. However, priority is determined by
* referring to the override map.
*
* If a key is marked as overwritten, then the secondary dataset is prioritized. If it does not contain the
* key, the primary dataset is returned.
*
* If a key is not marked as overwritten, then the primary dataset is prioritized. If it does not contain the key,
* then the secondary dataset is returned.
*
* @since 4.13
*
* @param int|string $key The key.
*
* @return DataSetInterface The data set to use.
*/
protected function getChildForKey($key)
{
if ($this->isOverridden($key)) {
return $this->secondary->offsetExists($key)
? $this->secondary
: $this->primary;
}
return $this->primary->offsetExists($key)
? $this->primary
: $this->secondary;
}
}