Namespaces

One important feature of IQL is the integration of Java types. The DSL can refer to Java types from Java standard libraries, Odysseus Bundles or other external libraries. Namespaces are useful in this context to refer Java types by a simple name and not by a fully qualified name. The static-keyword allows the static methods of a java class to be referenced without qualifying the class name.

Code Block

title	Grammar

ID

Class, Interface

Code Block

title	Grammar

Class                  ::= "class" ID ("extends" QName)? ("implements" QName ("," QName)*)? "{" (Attribute | Method)* "}". 
Interface              ::= ("interface" ID ("extends" QName ("," QName)*)? "{" (MethodDeclaration)* "}".
Attributea".."z"|"A".."Z"|"_")("a".."z"|"A".."Z"|"_"|"0".."9")*.
QName                   ::= VariableDeclarationID (VariableInit)? ";".
VariableDeclaration    ::= Type" ID.)*
TypeNamespace                   ::= (PrimitiveType | QName)"use" ("[static")? QualifiedNameWithWildcard "];")*.
PrimitiveType     QualifiedNameWildcard     ::= QualifiedName ("::*")?

Code Block

title	Example

use java::util::*;
use de::uniol::inf::is::odysseus::core::ISubscription;
use com::google::common::collect::ImmutableMap;

Class, Interface

Besides the integration of Java types it is also possible to create your own classes and interfaces.

Code Block

title	Grammar

Class         "boolean" | "byte" | "char" | "short" | "int" | "float" | "long" | "double".
Method         ::= "class" ID ("extends" QName)? ("implements"  QName ::= ("override," QName)*)? MethodDeclaration StatementBlock.  
MethodDeclaration"{" (Attribute | Method)* "}". 
Interface      ::= ID (MethodParameters)? (":" Type)?.
MethodParameters       ::= "interface" ID ("extends" (VariableDeclarationQName ("," VariableDeclarationQName)*)? "{" (MethodDeclaration)* ".

Code Block

title	Example Class

class Point implements IPoint{
}".
Attribute       int x;
    int y;
 ::= VariableDeclaration (VariableInit)? ";".
VariableDeclaration    Point(int x, int y) {
::= Type ID.
Type        this.x = x;
        this.y ::= y;
(PrimitiveType | QName)  }
("[" "]")*.
PrimitiveType    
    override getX() : int{
        return this.x;
    }
:= "boolean" | "byte" | "char" | "short" | "int" | "float" | "long" | "double".
Method    
    override getY() : int{
      ::=  return this.y;
    }    
}

Code Block

title	Example Interface

interface IPoint {
	getX() : int;
    getY() : int;
}

...

("override")? MethodDeclaration StatementBlock.  
MethodDeclaration      ::= ID (MethodParameters)? (":" Type)?.
MethodParameters       ::= "(" (VariableDeclaration ("," VariableDeclaration)*)? ")".

Code Block

title	GrammarExample Class

Statementclass Point implements IPoint{
    int x;
    int y;
 ::= ( StatementBlock |
 IfStatement | SwitchStatement | WhileStatement | DoWhileStatement | ForStatement | ForEachStatement
Point(int x, int y) {
        this.x = x;
        this.y = y;
    }
    
  | VariableStatement |override ConstructorStatementgetX() |: ExpressionStatementint{
 | BreakStatement |   ContinueStatement | ReturnStatementreturn )this.x;
StatementBlock    }
    
   ::= "{" (Statement)* "}".
IfStatement override getY() : int{
        return this.y;
    }    
}

Code Block

title	Example Interface

interface IPoint {
	getX() : int;
    getY() : int;
}

Statements

Methods, constructors and other blocks are sequences of statements. They can be divided into atomic and compound statements. Atomic statements are not made up of other statements and ends with a semicolon (e.g. VariableStatement). Compound statements (also called control structures) contain other statements (e.g. WhileStatement).

Code Block

title	Grammar

Statement     ::= "if" "(" Expression ")" Statement ("else" Statement)?.
SwitchStatement        ::= "switch" "(" Expression ")" "{" ("case" Expression ":" (Statement)*)* ("default" ":" (Statement)*)? "}"
WhileStatement         ::= "while" "(" Expression ")" Statement.
DoWhileStatement       ::= "do" Statement "while" "(" Expression ")" ";".
ForStatement( StatementBlock | IfStatement | SwitchStatement | WhileStatement | DoWhileStatement | ForStatement | ForEachStatement
                  ::= "for" "(" VariableDeclaration ";" Expression ";" Expression ")" Statement.
ForEachStatement       ::= "for" "(" VariableDeclaration ":" Expression ")" Statement.
VariableStatement | VariableStatement | ConstructorStatement | ExpressionStatement | BreakStatement | ContinueStatement | ReturnStatement ).
StatementBlock         ::= VariableDeclaration VariableInit"{" (Statement)* ";}".
ConstructorStatementIfStatement     ::= ("super" | "this")       ::= "if" "(" (ArgsList)?Expression ")" Statement (";else".
ExpressionStatement    ::= Expression ";".
BreakStatement Statement)?.
SwitchStatement         ::= "breakswitch" ";(".
ContinueStatement Expression     ::= "continue" ";".
ReturnStatement")" "{" ("case" Expression ":" (Statement)*)* ("default" ":" (Statement)*)? "}"
WhileStatement         ::= "returnwhile" "(" Expression)? ";)".

Code Block

title	Example if-Statement

int i = 2;
if (i>2) {
        Statement.
DoWhileStatement       ::= "do" Statement "while" "(" Expression ")" ";".
ForStatement     
}

Code Block

title	Example switch-Statement

int i = 2;   ::=   
switch(i) {
	case 2 :
		return true;
	case 4 : 
		return true;
	default :
		return false;
}

Code Block

title	Example while-Statement

int i = 2;   "for" "(" VariableDeclaration ";" Expression ";" Expression ")" Statement.
ForEachStatement       ::= "for" "(" VariableDeclaration ":" Expression ")" Statement.
VariableStatement      ::= VariableDeclaration 
while (i>2) {
VariableInit ";".
ConstructorStatement            
} 

do {
   ::= ("super" | "this") "(" (ArgsList)? ")" ";".
ExpressionStatement    ::= Expression ";".
BreakStatement         
} while (i>2);   ::= "break" ";".
ContinueStatement      ::= "continue" ";".
ReturnStatement         
::= "return" (Expression)? ";".

Code Block

title	Example forif-Statement

for (int ji = 02; j<10; j++
if (i>2) {

} 
        
List list = [1,2,3];
for (Object element : list) {
}
}

Code Block

title	Example object initialization

// Constructor Call
Point p1 = new Point(2, 5);
Point p2(2,5);

// Assigning attribute values
Point p3 = new Point{x = 2, y = 5};
Point p4{x = 2, y = 5};

Expressions

switch-Statement

int i = 2;      
switch(i) {
	case 2 :
		return true;
	case 4 : 
		return true;
	default :
		return false;
}

Code Block

title	Example while-Statement

int i = 2;

Code Block

title	Grammar

Expression           ::=
while (i>2) AssignmentExpression{
  | LogicalExpression | EqualityExpression | ArithmeticExpression | UnaryExpression |  
} 

do {
            
} while (i>2);

Code Block

title	Example for-Statement

for (int j = 0; j<10; j++) {

} 
        
List list = [1,2,3];
for (Object element : list) {

}

A new object can be created by calling a constructor. It is also possible to assign values to attributes in this context. This makes it easier to configure operators when building a query with QDL because it is not necessary to create a new statement for each parameter.

Code Block

title	Example object initialization

// Constructor Call
Point p1 = new Point(2, 5);
Point p2(2,5);

// Assigning attribute values
Point p3 = new Point{x = 2, y = 5};
Point p4{x = 2, y = 5};

Expressions

An expression is used as part of other expressions or statements and produces a value as result.

Code Block

title	Grammar

Expression           ::= ( AssignmentExpression | LogicalExpression | EqualityExpression | ArithmeticExpression | UnaryExpression | CastExpression
							| PrefixExpression | PostfixExpression | InstanceOfExpression | CreateExpression | AttributeExpression | MethodExpression
							| ArrayExpression | "this" | "super" | ID | LiteralExpression | ("(" Expression ")").
AssignmentExpression ::= Expression ("=" | "+=" | "-=" | "*=" | "/=" | "%=") Expression.
LogicalExpressionCastExpression
							| PrefixExpression | PostfixExpression | InstanceOfExpression | CreateExpression | AttributeExpression | MethodExpression
							| ArrayExpression | "this" | "super" | ID | LiteralExpression | ("(" Expression ")").
AssignmentExpression ::= Expression ("=" | "+=" | "-=" | "*=" | "/=" | "%=") Expression.
LogicalExpression    ::= Expression ("&&" | "||") Expression.
EqualityExpression   ::= Expression ("==" | "!=" | ">" | ">=" | "<" | "<=") Expression.
ArithmeticExpression ::= Expression ("+" | "-" | "*" | "/"| "%") Expression.                      
UnaryExpression      ::= ("+" | "-" | "!") Expression.
CastExpression       ::= "(" Type ")" Expression.
PrefixExpression     ::= ("++" | "--") Expression.
PostfixExpression    ::= Expression ("++&&" | "--||").
InstanceOfExpression ::= Expression "instanceof" Type.
NewExpressionEqualityExpression        ::= "new" QNameExpression (("[==" | "]!=") | (("(>" (ArgsList)?| ")")? ("{" ArgsMap "}")?)).
MemberCallExpression>=" | "<" | "<=") Expression.
ArithmeticExpression ::= (ExpressionExpression ("+" | ".-")? ID| ("(*" (ArgsList)? | "/"| ")%")?.
ArrayExpression Expression.          ::= Expression ("[" ArgsList "]")+.
LiteralExpression    ::= Integer | Double |
UnaryExpression Boolean | Char | String | Range::= ("+" | List"-" | Map | Null
VariableInit "!") Expression.
CastExpression        ::= ((("(" (ArgsList)?Type ")")? Expression.
PrefixExpression     ::= ("{++" ArgsMap| "}")?)--") Expression.
PostfixExpression    ::= Expression ("++" | ("=--" Expression)).
ArgsListInstanceOfExpression ::= Expression "instanceof" Type.
NewExpression         ::= Expression"new" QName ((",[" Expression)*.
ArgsMap             "]") | (("(" (ArgsList)? ")")? ("{" ArgsMap "}")?)).
MemberCallExpression ::= ArgsMapKeyValue (Expression ".")? ID (",(" ArgsMapKeyValue)*(ArgsList)? ")")?.
ArgsMapKeyValueArrayExpression      ::= IDExpression ("[" ArgsList "=" Expression

Metadata

Code Block

title	Grammar

Metadata               ::= ID "=" MetadataValue.
MetadataValue]")+.
LiteralExpression    ::= Integer | Double | Boolean | Char | String | Range | List | Map | Null
VariableInit          ::= MetadataValueSingle | MetadataValueList | MetadataValueMap.
MetadataValueSingle    ::= INTEGER | Double | CHAR | STRING | BOOLEAN | QName.
MetadataValueList((("(" (ArgsList)? ")")? ("{" ArgsMap "}")?) | ("=" Expression)).
ArgsList             ::= "["Expression (MetadataValue ("," MetadataValueExpression)*)? "]".
MetadataValueMapArgsMap              ::= "[" (MetadataValueMapEntryArgsMapKeyValue ("," MetadataValueMapEntryArgsMapKeyValue)*)? "]".
MetadataValueMapEntryArgsMapKeyValue      ::= MetadataValue ":" MetadataValue.

See operators in ODL or queries in QDL for examples.

...

ID "=" Expression

If a data type has a getter- or setter-method there will always be a corresponding attribute to access. So it is often possible to use assignment expressions instead of method calls.

Metadata

Code Block

title	Grammar

IntegerMetadata               ::= ID ::"= (0..9)+" MetadataValue.
DoubleMetadataValue          ::= MetadataValueSingle | MetadataValueList | MetadataValueMap.
MetadataValueSingle    ::= (0..9)* "." (0..9)+.
Boolean        INTEGER | Double | CHAR | STRING | BOOLEAN | QName.
MetadataValueList         ::= "[" (MetadataValue ("true" |," MetadataValue)*)? "false]").
CharMetadataValueMap       ::= "[" (MetadataValueMapEntry ("," MetadataValueMapEntry)*)? "]".
MetadataValueMapEntry  ::= MetadataValue ":" MetadataValue.

See operators in ODL or queries in QDL for examples.

Literals

Literals are sequence of characters that represent constant values to be stored in variables.

Code Block

title	Grammar

Integer    ::= "'" Unicode-Character "'".
String                  ::= '"' (Unicode-Character)* '"'.   
Range (0..9)+.
Double                  ::= (0..9)+* ".." (0..9)+.
ListBoolean                    ::= ("[true" (Expression| (",false" Expression)*)? "]".  
Map Char                    ::= "['" (MapKeyValueUnicode-Character (",'" MapKeyValue)*)? "]".
MapKeyValue.
String                  ::= Expression ":" Expression.
Null  '"' (Unicode-Character)* '"'.   
Range                   ::= "null".

Code Block

title	Example

Range r = 1..10;
List l  = [1, 2, 3];
Map m   = ["key1":1, "key2":2];

Identifier, Qualified Name, Namespace

Code Block

title	Grammar

ID (0..9)+ ".." (0..9)+.
List                    ::= "[" (Expression ("," Expression)*)? "]".  
Map                     ::= ("a".."z"|"A".."Z"|"_")("a".."z"|"A".."Z"|"_"|"0".."9")*.
QName[" (MapKeyValue ("," MapKeyValue)*)? "]".
MapKeyValue             ::= Expression ":" Expression.
Null                       ::= ID ("::" ID)*
Namespace              ::= "use" QualifiedNameWithWildcard ";".
QualifiedNameWildcard  ::= QualifiedName ("::*")?

Code Block

title	Example

use java::util::*;
use de::uniol::inf::is::odysseus::core::ISubscription;
use com::google::common::collect::ImmutableMap;

Java-Code

::= "null".

Code Block

title	Example

Range r = 1..10;
List l  = [1, 2, 3];
Map m   = ["key1":1, "key2":2];
Tuple t = [5, true, 3.4];
IPunctuation p = 100;

Java-Code

IQL-code is always translated into Java-code. Sometimes it might be useful to write Java-code directly instead of IQL-code.

Code Blockcode

title	Grammar

GPLCode                ::= "$*" GPL Code "*$"

Code Block

title	Example

$*
public static void main(String[] args) {
         
}
*$

Comments

IQL supports single- and multi-line comments.

Code Block

title	Grammar

Comment                 ::= SingeLineComment | MultiLineComment.
SingeLineComment        ::= "//" Text (("\r")? "\n")?.
MultiLineComment        ::= "/*" Text "*/".

...

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Versions Compared

Old Version 23

New Version 24

Key

Namespaces

Class, Interface

Class, Interface

Statements

Expressions

Expressions

Metadata

Metadata

Literals

Identifier, Qualified Name, Namespace

Java-Code

Java-Code

Comments

Space shortcuts

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Page History

Versions Compared

Old Version 23

New Version 24

Key

Namespaces

Class, Interface

Class, Interface

Statements

Expressions

Expressions

Metadata

Metadata

Literals

Identifier, Qualified Name, Namespace

Java-Code

Java-Code

Comments