LDAP検索式の構築(式ツリーを拡張)
前のロジックは「全ての関係式は2項式」って前提で書いたけど、一般的な数式のBNFみたいに「ANDが連続するならterm,ORが連続するならexpression」って思えば各ノードに2個以上の条件式を追加することができる。
括弧を単体の構造で表すのは面倒(beginParenthesisさせたらendParenthesisを忘れたりする)だからComplex構造を使う。言わばCompositeのノード。
前のロジックではComplexFilterとComplexFilterNodeに分けてたけど、今回はComplexFilterのみ。ノード用クラスは使わない。そのかわりComplexのルートノードになるオブジェクトは 必ず(OR式 -* AND式)になり、ANDのみからなる条件式はツリーのネストが1段階多い。じゃないとa OR B and C みたいな式でCを追加できない。
それではコードを。
class Expression{
public function compose(Composer $composer){}
}
class ComplexFilter extends Expression{
var $modifier;
var $operator;
var $filters;
public function __construct($operator = "OR"){
$this->modifier = "";
$this->operator = $operator;
$this->filters = array();
}
public function add($filter,$operator = "OR"){
$childCount = count($this->filters);
$last = $this->lastChild();
if($last == null){
$this->filters[] = $filter;
}
else{
if($this->operator == $operator){
$this->filters[] = $filter;
}
else{
$this->addToLast($filter,$operator);
}
}
return $this;
}
public function addAnd($filter){
return $this->add($filter,"AND");
}
public function addOr($filter){
return $this->add($filter,"OR");
}
public function setModifier($mod){
$this->modifier = $mod;
}
public function compose(Composer $composer){
$composer->composeComplex($this);
}
function lastChild(){
$childCount = count($this->filters);
if($childCount == 0){
return null;
}
return $this->filters[$childCount -1];
}
function addToLast($filter,$operator){
$childCount = count($this->filters);
$last = $this->lastChild();
if($last instanceof ComplexFilter){
if($last->operator == $operator){
$last->add($filter,$operator);
}
else{
$this->filters[$childCount -1] = $this->createComplex($last,$filter,$operator);
}
}
else{
$this->filters[$childCount -1] = $this->createComplex($last,$filter,$operator);
}
}
function createComplex($filter1,$filter2,$operator){
$complex = new ComplexFilter($operator);
$complex->add($filter1,$operator);
$complex->add($filter2,$operator);
return $complex;
}
}
class TextFilter extends Expression{
var $text;
public function __construct($text){
$this->text = $text;
}
public function compose(Composer $composer){
$composer->composeText($this);
}
}
class ExpressionFactory{
public function text($text){
return new TextFilter($text);
}
public function complex(){
return new ComplexFilter();
}
}
class Composer{
var $text;
public function composeText(TextFilter $filter){
$this->text = $filter->text;
}
public function composeComplex(ComplexFilter $filter){
$operator = $filter->operator;
$this->text = "";
$text = "";
foreach($filter->filters as $node){
if($text != ""){
$text .= " " . $filter->operator . " ";
}
$node->compose($this);
$text .= $this->text;
}
if(count($filter->filters)>1){
$this->text = "(".$text.")";
}
else{
$this->text = $text;
}
}
}
class LdapComposer extends Composer{
var $text;
public function composeText(TextFilter $filter){
$this->text = "(". $filter->text .")";
}
public function composeComplex(ComplexFilter $filter){
$operator = $filter->operator == "AND" ? "&" : "|";
$this->text = "";
$text = "";
foreach($filter->filters as $node){
$node->compose($this);
$text .= $this->text;
}
if(count($filter->filters)>1){
$this->text = "(".$operator .$text.")";
}
else{
$this->text = $text;
}
}
}
$composer = new Composer();
$expr = new ExpressionFactory();
//1 . A=1
$filter = $expr->text("A=1");
$filter->compose($composer);
echo "A=1 : ";
echo $composer->text. "<br />";
//2 . A=1
$filter = $expr->complex()
->addAnd($expr->text("A=1"))
;
$filter->compose($composer);
echo "A=1 : ";
echo $composer->text. "<br />";
//3 . A=1 and B=1
$filter = $expr->complex()
->addAnd($expr->text("A=1"))
->addAnd($expr->text("B=1"))
;
$filter->compose($composer);
echo "A=1 and B=1 ";
echo $composer->text. "<br />";
//4 . A=1 and B=1 and C=2
$filter = $expr->complex()
->add($expr->text("A=1"))
->addAnd($expr->text("B=1"))
->addAnd($expr->text("C=2"))
;
$filter->compose($composer);
echo "A=1 and B=1 and C=2 :";
echo $composer->text. "<br />";
//5 . A=1 and B=1 or C=2
$filter = $expr->complex()
->addAnd($expr->text("A=1"))
->addAnd($expr->text("B=1"))
->addOr($expr->text("C=2"))
;
$filter->compose($composer);
echo $composer->text. "<br />";
//6 . A=1 or B=1 and C=2
$filter = $expr->complex()
->addAnd($expr->text("A=1"))
->addOr($expr->text("B=1"))
->addAnd($expr->text("C=2"))
;
$filter->compose($composer);
echo $composer->text. "<br />";
//7 . A=1 and B=1 or C=2 and D=3
$filter = $expr->complex()
->addAnd($expr->text("A=1"))
->addAnd($expr->text("B=1"))
->addOr($expr->text("C=2"))
->addAnd($expr->text("D=3"))
;
$filter->compose($composer);
echo $composer->text. "<br />";
//8 . (A=1 or B=1)
$filter = $expr->complex()
->add(
$expr->complex()
->add($expr->text("A=1"))
->addOr($expr->text("B=1"))
)
;
$filter->compose($composer);
echo $composer->text. "<br />";
echo "<br />";
//9 . (A=1 or B=1) and (C=2 or D=3)
$filter = $expr->complex()
->add(
$expr->complex()
->add($expr->text("A=1"))
->addOr($expr->text("B=1"))
->addOr($expr->text("B=2"))
)
->addAnd(
$expr->complex()
->add($expr->text("C=2"))
->addOr($expr->text("D=3"))
)
;
$filter->compose($composer);
echo $composer->text. "<br />";
echo "<br />";
//10 . (A=1 or B=1) or (C=2 or D=3)
$filter = $expr->complex()
->add(
$expr->complex()
->add($expr->text("A=1"))
->addOr($expr->text("B=1"))
)
->addOr(
$expr->complex()
->add($expr->text("C=2"))
->addOr($expr->text("D=3"))
)
;
$filter->compose($composer);
echo $composer->text. "<br />";
echo "<br />";
//10 . (A=1 or B=1) and (C=2 or D=3 and ( E=1 or F=2) )
$filter = $expr->complex()
->add(
$expr->complex()
->add($expr->text("A=1"))
->addOr($expr->text("B=1"))
)
->addOr(
$expr->complex()
->addAnd($expr->complex()->add($expr->text("E=1"))->addOr($expr->text("F=2")))
->addAnd($expr->text("C=2"))
->addOr($expr->text("D=3"))
)
;
$filter->compose($composer);
echo $composer->text. "<br />";
echo "<br />";
Composerクラスは本当はabstractになるべきで、DatabaseExpressionComposerとLdapExpressionComposerなどに分かれるべき。なぜかといえば「せっかく継承するのに親クラスのコードを一切使わないなら継承はしてはならない」から。シグネーチャをあわせるならインターフェースか抽象クラスを使うべき。
ところでComposerクラスの存在は微妙(デザインパターン的な意味で)なんだが、これはVisitorと思っていいんだろうか？
