EL-expression

Compiled expression

Identifiers - one of the variables available in scope

Additional identifiers can be declared via <cdk:object> tag

#{component}

#{clientId}

component

clientId

Values - combination of expressions

#{facesContext.externalContext}

#{component.children[0]}

facesContext.getExternalContext()

component.getChildren().get(0)

Integer, string, double, boolean literals

#{'some string'}

#{5}

#{2.718}

#{true}

#{false}

"some string"

5

Double.valueOf(2.718)

true

false

Null expression

#{null}

null

Arithmetic operations

(in the following examples 'a' and 'b' are number value identifiers)

#{a + b}

#{a - b}

#{a * b}

#{a / b}

#{a div b}

#{a % b}

#{a mod b}

#{-a}

a + b

a – b

a * b

a / b

a % b

a % b

a % b

-a

Boolean operations

(in the following examples 'a' and 'b' are boolean value identifiers)

#{a and b}

#{a && b}

#{a or b}

#{a || b}

#{not a}

#{!a}

a && b

a && b

a || b

a || b

!a

!a

Comparison operations

(in the following examples 'a' and 'b' are number value identifiers)

#{a > b}

#{a gt b}

#{a < b}

#{a lt b}

#{a >= b}

#{a ge b}

#{a <= b}

#{a le b}

a > b

a > b

a < b

a < b

a >= b

a >= b

a <= b

a <= b

Equality test operations

#{a == b}

#{a eq b}

#{a == null}

#{a eq null}

#{a != null}

#{a ne null}

#{a != b}

#{a ne b}

If 'a' & 'b' are both primitive types:

a == b

otherwise:

isEqual(a, b)

If 'a' is non-primitive type:

a == null

otherwise

isEqual(a, null)

If 'a' is non-primitive type:

a != null

otherwise

!isEqual(a, null)

If 'a' & 'b' are both primitive types:

a != b

otherwise:

!isEqual(a, b)

Choice operator

(in the following example 'a' and 'b' are arbitrary expressions and 'test' is boolean value expression)

Type of the expression is determined by the type of 'a' expression, unless 'a' has unknown type (e.g. it's equivalent to 'null' identifier)

#{test ? a : b}

test ? a : b

Bracket expression

If 'l' is array:

#{l[i]}

otherwise:

#{m[key]}

l[i]

m.get(key)

Property expression

(in the following examples 'o' is arbitrary object value)

#{o.myProperty}

#{o.name}

o.getMyProperty()

o.getName()

Empty operator

(in the following examples 'o' is arbitrary object value)

#{empty o}

isEmpty(o)

Method expression

(in the following examples 'o' is arbitrary object value that has

String computeValue(String)

and

String toString() methods)

#{o.computeValue('test')}

#{o.toString()}

o.computeValue("test")

o.toString()

Function expression

#{variableName:methodName(arg0, ..., argN)}

#{methodName(arg0, ..., argN)}

variableName.methodName(arg0, ..., argN)

this.methodName(arg0, ..., argN)

Deferred expression - composition of several aforementioned expressions

#{(a ne null) ? cc.attributes['name'] : 'default'}

a != null ? (cc.getAttributes().get("name")) : ("default")

Mixed expression

#{clientId}:suffix

"clientId" + ":suffix"