<?php
/**
* Zend Framework
*
* LICENSE
*
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://framework.zend.com/license/new-bsd
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@zend.com so we can send you a copy immediately.
*
* @category Zend
* @package Zend_Search_Lucene
* @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: FSM.php 24594 2012-01-05 21:27:01Z matthew $
*/
/** Zend_Search_Lucene_FSMAction */
require_once 'Zend/Search/Lucene/FSMAction.php';
/**
* Abstract Finite State Machine
*
* Take a look on Wikipedia state machine description: http://en.wikipedia.org/wiki/Finite_state_machine
*
* Any type of Transducers (Moore machine or Mealy machine) also may be implemented by using this abstract FSM.
* process() methods invokes a specified actions which may construct FSM output.
* Actions may be also used to signal, that we have reached Accept State
*
* @category Zend
* @package Zend_Search_Lucene
* @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
abstract class Zend_Search_Lucene_FSM
{
/**
* Machine States alphabet
*
* @var array
*/
private $_states = array();
/**
* Current state
*
* @var integer|string
*/
private $_currentState = null;
/**
* Input alphabet
*
* @var array
*/
private $_inputAphabet = array();
/**
* State transition table
*
* [sourceState][input] => targetState
*
* @var array
*/
private $_rules = array();
/**
* List of entry actions
* Each action executes when entering the state
*
* [state] => action
*
* @var array
*/
private $_entryActions = array();
/**
* List of exit actions
* Each action executes when exiting the state
*
* [state] => action
*
* @var array
*/
private $_exitActions = array();
/**
* List of input actions
* Each action executes when entering the state
*
* [state][input] => action
*
* @var array
*/
private $_inputActions = array();
/**
* List of input actions
* Each action executes when entering the state
*
* [state1][state2] => action
*
* @var array
*/
private $_transitionActions = array();
/**
* Finite State machine constructor
*
* $states is an array of integers or strings with a list of possible machine states
* constructor treats fist list element as a sturt state (assignes it to $_current state).
* It may be reassigned by setState() call.
* States list may be empty and can be extended later by addState() or addStates() calls.
*
* $inputAphabet is the same as $states, but represents input alphabet
* it also may be extended later by addInputSymbols() or addInputSymbol() calls.
*
* $rules parameter describes FSM transitions and has a structure:
* array( array(sourseState, input, targetState[, inputAction]),
* array(sourseState, input, targetState[, inputAction]),
* array(sourseState, input, targetState[, inputAction]),
* ...
* )
* Rules also can be added later by addRules() and addRule() calls.
*
* FSM actions are very flexible and may be defined by addEntryAction(), addExitAction(),
* addInputAction() and addTransitionAction() calls.
*
* @param array $states
* @param array $inputAphabet
* @param array $rules
*/
public function __construct($states = array(), $inputAphabet = array(), $rules = array())
{
$this->addStates($states);
$this->addInputSymbols($inputAphabet);
$this->addRules($rules);
}
/**
* Add states to the state machine
*
* @param array $states
*/
public function addStates($states)
{
foreach ($states as $state) {
$this->addState($state);
}
}
/**
* Add state to the state machine
*
* @param integer|string $state
*/
public function addState($state)
{
$this->_states[$state] = $state;
if ($this->_currentState === null) {
$this->_currentState = $state;
}
}
/**
* Set FSM state.
* No any action is invoked
*
* @param integer|string $state
* @throws Zend_Search_Exception
*/
public function setState($state)
{
if (!isset($this->_states[$state])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('State \'' . $state . '\' is not on of the possible FSM states.');
}
$this->_currentState = $state;
}
/**
* Get FSM state.
*
* @return integer|string $state|null
*/
public function getState()
{
return $this->_currentState;
}
/**
* Add symbols to the input alphabet
*
* @param array $inputAphabet
*/
public function addInputSymbols($inputAphabet)
{
foreach ($inputAphabet as $inputSymbol) {
$this->addInputSymbol($inputSymbol);
}
}
/**
* Add symbol to the input alphabet
*
* @param integer|string $inputSymbol
*/
public function addInputSymbol($inputSymbol)
{
$this->_inputAphabet[$inputSymbol] = $inputSymbol;
}
/**
* Add transition rules
*
* array structure:
* array( array(sourseState, input, targetState[, inputAction]),
* array(sourseState, input, targetState[, inputAction]),
* array(sourseState, input, targetState[, inputAction]),
* ...
* )
*
* @param array $rules
*/
public function addRules($rules)
{
foreach ($rules as $rule) {
$this->addrule($rule[0], $rule[1], $rule[2], isset($rule[3])?$rule[3]:null);
}
}
/**
* Add symbol to the input alphabet
*
* @param integer|string $sourceState
* @param integer|string $input
* @param integer|string $targetState
* @param Zend_Search_Lucene_FSMAction|null $inputAction
* @throws Zend_Search_Exception
*/
public function addRule($sourceState, $input, $targetState, $inputAction = null)
{
if (!isset($this->_states[$sourceState])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('Undefined source state (' . $sourceState . ').');
}
if (!isset($this->_states[$targetState])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('Undefined target state (' . $targetState . ').');
}
if (!isset($this->_inputAphabet[$input])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('Undefined input symbol (' . $input . ').');
}
if (!isset($this->_rules[$sourceState])) {
$this->_rules[$sourceState] = array();
}
if (isset($this->_rules[$sourceState][$input])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('Rule for {state,input} pair (' . $sourceState . ', '. $input . ') is already defined.');
}
$this->_rules[$sourceState][$input] = $targetState;
if ($inputAction !== null) {
$this->addInputAction($sourceState, $input, $inputAction);
}
}
/**
* Add state entry action.
* Several entry actions are allowed.
* Action execution order is defined by addEntryAction() calls
*
* @param integer|string $state
* @param Zend_Search_Lucene_FSMAction $action
*/
public function addEntryAction($state, Zend_Search_Lucene_FSMAction $action)
{
if (!isset($this->_states[$state])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('Undefined state (' . $state. ').');
}
if (!isset($this->_entryActions[$state])) {
$this->_entryActions[$state] = array();
}
$this->_entryActions[$state][] = $action;
}
/**
* Add state exit action.
* Several exit actions are allowed.
* Action execution order is defined by addEntryAction() calls
*
* @param integer|string $state
* @param Zend_Search_Lucene_FSMAction $action
*/
public function addExitAction($state, Zend_Search_Lucene_FSMAction $action)
{
if (!isset($this->_states[$state])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('Undefined state (' . $state. ').');
}
if (!isset($this->_exitActions[$state])) {
$this->_exitActions[$state] = array();
}
$this->_exitActions[$state][] = $action;
}
/**
* Add input action (defined by {state, input} pair).
* Several input actions are allowed.
* Action execution order is defined by addInputAction() calls
*
* @param integer|string $state
* @param integer|string $input
* @param Zend_Search_Lucene_FSMAction $action
*/
public function addInputAction($state, $inputSymbol, Zend_Search_Lucene_FSMAction $action)
{
if (!isset($this->_states[$state])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('Undefined state (' . $state. ').');
}
if (!isset($this->_inputAphabet[$inputSymbol])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('Undefined input symbol (' . $inputSymbol. ').');
}
if (!isset($this->_inputActions[$state])) {
$this->_inputActions[$state] = array();
}
if (!isset($this->_inputActions[$state][$inputSymbol])) {
$this->_inputActions[$state][$inputSymbol] = array();
}
$this->_inputActions[$state][$inputSymbol][] = $action;
}
/**
* Add transition action (defined by {state, input} pair).
* Several transition actions are allowed.
* Action execution order is defined by addTransitionAction() calls
*
* @param integer|string $sourceState
* @param integer|string $targetState
* @param Zend_Search_Lucene_FSMAction $action
*/
public function addTransitionAction($sourceState, $targetState, Zend_Search_Lucene_FSMAction $action)
{
if (!isset($this->_states[$sourceState])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('Undefined source state (' . $sourceState. ').');
}
if (!isset($this->_states[$targetState])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('Undefined source state (' . $targetState. ').');
}
if (!isset($this->_transitionActions[$sourceState])) {
$this->_transitionActions[$sourceState] = array();
}
if (!isset($this->_transitionActions[$sourceState][$targetState])) {
$this->_transitionActions[$sourceState][$targetState] = array();
}
$this->_transitionActions[$sourceState][$targetState][] = $action;
}
/**
* Process an input
*
* @param mixed $input
* @throws Zend_Search_Exception
*/
public function process($input)
{
if (!isset($this->_rules[$this->_currentState])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('There is no any rule for current state (' . $this->_currentState . ').');
}
if (!isset($this->_rules[$this->_currentState][$input])) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('There is no any rule for {current state, input} pair (' . $this->_currentState . ', ' . $input . ').');
}
$sourceState = $this->_currentState;
$targetState = $this->_rules[$this->_currentState][$input];
if ($sourceState != $targetState && isset($this->_exitActions[$sourceState])) {
foreach ($this->_exitActions[$sourceState] as $action) {
$action->doAction();
}
}
if (isset($this->_inputActions[$sourceState]) &&
isset($this->_inputActions[$sourceState][$input])) {
foreach ($this->_inputActions[$sourceState][$input] as $action) {
$action->doAction();
}
}
$this->_currentState = $targetState;
if (isset($this->_transitionActions[$sourceState]) &&
isset($this->_transitionActions[$sourceState][$targetState])) {
foreach ($this->_transitionActions[$sourceState][$targetState] as $action) {
$action->doAction();
}
}
if ($sourceState != $targetState && isset($this->_entryActions[$targetState])) {
foreach ($this->_entryActions[$targetState] as $action) {
$action->doAction();
}
}
}
public function reset()
{
if (count($this->_states) == 0) {
require_once 'Zend/Search/Exception.php';
throw new Zend_Search_Exception('There is no any state defined for FSM.');
}
$this->_currentState = $this->_states[0];
}
}