This returns the value for a key from bagInfoData.

@param string $key This is the key to get the value associated with.

@return string|null
@author Eric Rochester <erochest@virginia.edu>
494925
public function getBagInfoData($key)
    {
        $this->_ensureBagInfoData();
        return array_key_exists($key, $this->bagInfoData) ? $this->bagInfoData[$key] : null;
    }
655638
protected function retrieve($key)
    {
        if (array_key_exists($key, $this->storage)) {
            return $this->storage[$key];
        }

        return null;
    }
1065160
public function get( $key )
	{
		if ( isset($this->getData[ $key ]) )
		{
			return $this->getData[ $key ];
		}
		else
		{
			return null;
		}
	}
969519
public function get($key)
	{
		if ( ! isset($this->strings[$key]))
		{
			return null;
		}

		return $this->strings[$key];
	}
642439
public function getConfigList($key = null)
    {
        if (is_null($key)) {
            return $this->configList; // no key requested, return the entire configuration bag
        } elseif (empty($this->configList[$key])) {
            return null; // no such key
        } else {
            return $this->configList[$key]; // return the requested key
        }
    }
600831
public function retrieve(string $key)
  {
    $file = $this->file;

    if (file_exists($file)) {
      $data = unserialize($this->decrypt(file_get_contents($file)));

      if (isset($data[$key])) {
        return $data[$key];
      }
    }

    return null;
  }
966751
protected function getValuesFromKeyMap( $key )
    {
        if ( empty( $key ) || empty( $this->keyMap[$key] ) )
        {
            return null;
        }

        return $this->keyMap[$key];
    }
515097
public function get($key) {
		$filename = $this->getFileName($key);

		if ( ! is_file($filename)) {
			if ($this->log) {
				if ($this->log instanceof LoggerInterface) {
					$this->log->info("Retrieving key '{key}' from file cache: cache miss.", array('key'=>$key));
				} else {
					$this->log->trace("Retrieving key '$key' from file cache: cache miss.");
				}
			}
			return null;
		}
		$value = include $filename;

		if ($value['lifetime'] !== 0 && $value['lifetime'] < time()) {
			if ($this->log) {
				if ($this->log instanceof LoggerInterface) {
					$this->log->info("Retrieving key '{key}' from file cache: key outdated, cache miss.", array('key'=>$key));
				} else {
					$this->log->trace("Retrieving key '$key' from file cache: key outdated, cache miss.");
				}
			}
			return null;
		}

		if ($this->log) {
			if ($this->log instanceof LoggerInterface) {
				$this->log->info("Retrieving key '{key}' from file cache.", array('key'=>$key));
			} else {
				$this->log->trace("Retrieving key '$key' from file cache.");
			}
		}

		return $value['data'];
	}
316078
public function get($key) {
		
		if (isset($this->_data[$key])) {
			return $this->_data[$key];
		}
		
		if (isset($this->registered[$key])) {
			return $this->_data[$key] = call_user_func($this->registered[$key], $this);
		}
		
		return null;	
	}
673775
public function getKey($key)
	{
		return isset($this->data[$key]) ? $this->data[$key] : null;
	}
256615
protected function transactionValue($key)
    {
        if (isset($this->data->transaction) && $this->data->transaction && isset($this->data->transaction->$key)) {
            return $this->data->transaction->$key;
        }

        return null;
    }
356350
public function getValue($key)
    {
        return isset($this->langstrings[$key]) ? $this->langstrings[$key] : null;
    }
1208400
public function getValue($key)
    {
        return array_key_exists($key, $this->data)
            ? $this->data[$key]
            : null;
    }
22011
public function item($key)
	{
		if ( ! isset($this->info['items'][$key]))
		{
			return null;
		}

		return $this->info['items'][$key];
	}
1077124
public function get(string $key)
    {
        $slug = $this->splitKey($key);

        if (is_string($slug)) {
            if (isset($this[$slug])) {
                return $this[$slug];
            }
            return null;
        }

        $array = $this->toArray();

        foreach ($slug as $search) {
            if (isset($array[$search])) {
                $array = $array[$search];
            } else {
                return;
            }
        }

        return $array;
    }
104701
public function getKey($key)
    {
        $key = strtolower($key);
        if (!isset($this->keys[$key])) {
            return null;
        }
        return (string)$this->keys[$key];
    }
713835
public function getValue($key)
    {
        if (!isset($this->values[$key])) {
            return null;
        }
        return $this->values[$key];
    }