org.expressionj.model

Interface Expression

All Superinterfaces:

java.lang.Cloneable, ExpressionType

All Known Subinterfaces:

AryExpression, Equation, MultipleAryExpression, UnaryExpression, Value

All Known Implementing Classes:

AbstractAryExpression, AbstractAryNumericExpression, AbstractAssignment, AbstractExpression, AbstractExprFunction, AbstractScalarAssignment, AbstractUnaryExpression, AbstractUnaryNumericExpression, AbstractValue, CodeBlock, Constant, ExprABS, ExprACOS, ExprADD, ExprAddAssignment, ExprAffectation, ExprAND, ExprArray, ExprArrayAffect, ExprArrayIndex, ExprASIN, ExprATAN, ExprATAN2, ExprBREAK, ExprCEIL, ExprCHOICE, ExprCOS, ExprDecrement, ExprDIV, ExprDivAssignment, ExprECHO, ExprEQ, ExprFLOOR, ExprFORMAT, ExprFunction, ExprGE, ExprGT, ExprIncrement, ExprLE, ExprLT, ExprMOD, ExprMULT, ExprMultAssignment, ExprNEQ, ExprNOT, ExprOR, ExprPOW, ExprSIGN, ExprSIN, ExprSQRT, ExprSUB, ExprSubAssignment, ExprTAN, ExprToDegrees, ExprToRadians, ExprWHILE, ExprXOR, LocalConstant, LocalVariable, ParsedEquation, Structure, Structure.Field, Variable

public interface Expression
extends ExpressionType, java.lang.Cloneable

Repredent any expression that can be evaluated. Expressions can be of several different kinds:

• AryExpression: an expression with two predicates, as for example AND
• UnaryExpression: an expression with one predicate, as for example NOT
• Variable: a Variable
• Constant: a Constant

Field Summary

Fields inherited from interface org.expressionj.model.ExpressionType

STRUCT_ARRAY, STRUCT_SCALAR, STRUCT_STRUCTURE, TYPE_BOOL, TYPE_DYNAMIC, TYPE_FLOAT, TYPE_INTEGER, TYPE_NUMERIC, TYPE_STRING, TYPE_UNDEF

Method Summary

Modifier and Type	Method and Description
java.lang.Object	clone()
java.lang.Object	eval() Evaluate the expression.
boolean	evalAsBoolean() Evaluate the expression as a boolean.
float	evalAsFloat() Evaluate the expression as a float.
int	evalAsInt() Evaluate the expression as an int.
default Expression	getExpression() Return the associated expression.
java.lang.String	getExpressionName() Return the expression name.
default LocalVariable	getLocalVariable(java.lang.String varName) Return the local variable of a specified name.
default java.util.Map<java.lang.String,LocalVariable>	getLocalVariables() Return the local variables used by this expression.
CodeBlock	getParentBlock() Return the parent expression block if the expression is one of several expressions separated by commas.
short	getResultStructure() Return the structure of the result for the expression.
short	getResultType() Return the type of the result for the expression.
Expression	getRoot() Return the root expression.
default Variable	getVariable(java.lang.String varName) Return a variable declared by the expression.
default Variable	getVariable(java.lang.String varName, boolean includeLocals) Return a variable declared by the expression.
java.util.Map<java.lang.String,Variable>	getVariables() Return the variables used by this expression.
default java.util.Map<java.lang.String,Variable>	getVariables(boolean includeLocals) Return the variables used by this expression, possibly including local variables.
default boolean	hasVariable(java.lang.String varName) Return true if there is a variable with a specified name.
default boolean	hasVariable(java.lang.String varName, boolean includeLocals) Return true if there is a variable with a specified name.
default Variable	removeVariable(java.lang.String varName) Remove a variable from the expression.
void	setParentBlock(CodeBlock block) Set the parent expression block.

Method Detail

getExpression

default Expression getExpression()

Return the associated expression. Return this by default.

Returns:

the associated expression

getRoot

Expression getRoot()

Return the root expression.

Returns:

the root expression

clone

java.lang.Object clone()
                throws java.lang.CloneNotSupportedException

Throws:

java.lang.CloneNotSupportedException

setParentBlock

void setParentBlock(CodeBlock block)

Set the parent expression block.

Parameters:

block - the parent expression block

getParentBlock

CodeBlock getParentBlock()

Return the parent expression block if the expression is one of several expressions separated by commas. For example, in the following equation: b=a+2; return b, the two "b=a+2" and "return b" have "b=a+2; return b" as their parent block.

Returns:

the parent expression block

evalAsInt

int evalAsInt()

Evaluate the expression as an int. The result of the evaluation will be the same as eval(), but the evaluation engine will be able to optimize the computation by knwoing that the result is an int (primitive valeus are cached internally).

Returns:

the result as an int

evalAsFloat

float evalAsFloat()

Evaluate the expression as a float. The result of the evaluation will be the same as eval(), but the evaluation engine will be able to optimize the computation by knwoing that the result is a float (primitive valeus are cached internally).

Returns:

the result as a float

evalAsBoolean

boolean evalAsBoolean()

Evaluate the expression as a boolean. The result of the evaluation will be the same as eval(), but the evaluation engine will be able to optimize the computation by knwoing that the result is a boolean (primitive valeus are cached internally).

Returns:

the result as a boolean

eval

java.lang.Object eval()

Evaluate the expression.

Returns:

the result

getResultType

short getResultType()

Return the type of the result for the expression. The type can be:

• ExpressionType.TYPE_INTEGER: integer
• ExpressionType.TYPE_FLOAT: float
• ExpressionType.TYPE_NUMERIC: integer or float value. The runtime actual type may depend on the expression arguments
• ExpressionType.TYPE_STRING: string
• ExpressionType.TYPE_DYNAMIC: dynamic type. The runtime actual type may depend on the expression arguments
• ExpressionType.TYPE_UNDEF: undefined type. The default type, characteristic of an error if entountered.

Returns:

the type of the result for the expression

getResultStructure

short getResultStructure()

Return the structure of the result for the expression. The structure can be:

• ExpressionType.STRUCT_SCALAR: a scalar value
• ExpressionType.STRUCT_ARRAY: an array value

Returns:

he structure of the result for the expression

getExpressionName

java.lang.String getExpressionName()

Return the expression name.

Returns:

the expression name

getVariables

java.util.Map<java.lang.String,Variable> getVariables()

Return the variables used by this expression. Note that this method will not return any internal variables declared by the expression. For example, in the following expression: int c=a+b, only "a" and "b" will be returned.

Returns:

the variables used by this expression

removeVariable

default Variable removeVariable(java.lang.String varName)

Remove a variable from the expression.

Parameters:

varName - the variable name

Returns:

the removed variable or null if there was no variable of this name

getVariables

default java.util.Map<java.lang.String,Variable> getVariables(boolean includeLocals)

Return the variables used by this expression, possibly including local variables.

Parameters:

includeLocals - true if local variables should be included

Returns:

the variables used by this expression

getLocalVariables

default java.util.Map<java.lang.String,LocalVariable> getLocalVariables()

Return the local variables used by this expression. Return an empty Map by default.

Returns:

the variables used by this expression

getLocalVariable

default LocalVariable getLocalVariable(java.lang.String varName)

Return the local variable of a specified name. Return null by default.

Parameters:

varName - the variable name

Returns:

the variable

getVariable

default Variable getVariable(java.lang.String varName)

Return a variable declared by the expression.

Parameters:

varName - the variable name

Returns:

the variable

hasVariable

default boolean hasVariable(java.lang.String varName)

Return true if there is a variable with a specified name.

Parameters:

varName - the variable name

Returns:

true if there is a variable with the specified name

getVariable

default Variable getVariable(java.lang.String varName,
                             boolean includeLocals)

Return a variable declared by the expression. The default implementation defer to getVariable(java.lang.String).

Parameters:

varName - the variable name

includeLocals - true if local variables should be included

Returns:

the variable

hasVariable

default boolean hasVariable(java.lang.String varName,
                            boolean includeLocals)

Return true if there is a variable with a specified name.

Parameters:

varName - the variable name

includeLocals - true if local variables should be included

Returns:

true if there is a variable with the specified name