Expression (PlantUML 1.2019.1)

java.lang.Object
- net.sourceforge.plantuml.evalex.Expression

```
public class Expression
extends java.lang.Object
```
EvalEx - Java Expression Evaluator

Introduction
EvalEx is a handy expression evaluator for Java, that allows to evaluate simple mathematical and boolean expressions.
For more information, see: EvalEx GitHub repository
- The software is licensed under the MIT Open Source license (see LICENSE file).
- The *power of* operator (^) implementation was copied from Stack Overflow. Thanks to Gene Marin.
- The SQRT() function implementation was taken from the book The Java Programmers Guide To numerical Computing (Ronald Mak, 2002).
See Also:

GitHub repository

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`Expression.ExpressionException` The expression evaluators exception class.
`class`	`Expression.Function` Abstract definition of a supported expression function.
`class`	`Expression.LazyFunction`
`static interface`	`Expression.LazyNumber` LazyNumber interface created for lazily evaluated functions
`class`	`Expression.Operator` Abstract definition of a supported operator.
`class`	`Expression.UnaryOperator`

Field Summary

Fields
Modifier and Type	Field and Description
`static java.math.BigDecimal`	`e` Definition of e: "Euler's number" as a constant, can be used in expressions as variable.
`static int`	`OPERATOR_PRECEDENCE_ADDITIVE` Additive operators precedence: + and -
`static int`	`OPERATOR_PRECEDENCE_AND` And operator precedence: &&
`static int`	`OPERATOR_PRECEDENCE_COMPARISON` Comparative operators precedence: <,>,<=,>=
`static int`	`OPERATOR_PRECEDENCE_EQUALITY` Equality operators precedence: =, ==, !=.
`static int`	`OPERATOR_PRECEDENCE_MULTIPLICATIVE` Multiplicative operators precedence: *,/,%
`static int`	`OPERATOR_PRECEDENCE_OR` Or operator precedence: \|\|
`static int`	`OPERATOR_PRECEDENCE_POWER` Power operator precedence: ^
`static int`	`OPERATOR_PRECEDENCE_UNARY` Unary operators precedence: + and - as prefix
`static java.math.BigDecimal`	`PI` Definition of PI as a constant, can be used in expressions as variable.

Constructor Summary

Constructors
Constructor and Description
`Expression(java.lang.String expression)` Creates a new expression instance from an expression string with a given default match context of `MathContext.DECIMAL32`.
`Expression(java.lang.String expression, java.math.MathContext defaultMathContext)` Creates a new expression instance from an expression string with a given default match context.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Function`	`addFunction(Function function)` Adds a function to the list of supported functions
`LazyFunction`	`addLazyFunction(LazyFunction function)` Adds a lazy function function to the list of supported functions
`<OPERATOR extends LazyOperator> OPERATOR`	`addOperator(OPERATOR operator)` Adds an operator to the list of supported operators.
`Expression`	`and(java.lang.String variable, java.math.BigDecimal value)` Sets a variable value.
`Expression`	`and(java.lang.String variable, Expression.LazyNumber value)` Sets a variable value.
`Expression`	`and(java.lang.String variable, java.lang.String value)` Sets a variable value.
`boolean`	`equals(java.lang.Object o)`
`java.lang.Number`	`eval()` Evaluates the expression.
`java.lang.Number`	`eval(boolean stripTrailingZeros)` Evaluates the expression.
`java.util.Set<java.lang.String>`	`getDeclaredFunctions()` Exposing declared functions.
`java.util.Set<java.lang.String>`	`getDeclaredOperators()` Exposing declared operators in the expression.
`java.util.Set<java.lang.String>`	`getDeclaredVariables()` Exposing declared variables in the expression.
`java.lang.String`	`getExpression()`
`java.util.Iterator<net.sourceforge.plantuml.evalex.Expression.Token>`	`getExpressionTokenizer()` Get an iterator for this expression, allows iterating over an expression token by token.
`java.lang.String`	`getOriginalExpression()` The original expression used to construct this expression, without variables substituted.
`java.util.List<java.lang.String>`	`getUsedVariables()` Returns a list of the variables in the expression.
`int`	`hashCode()`
`boolean`	`isBoolean()` Checks whether the expression is a boolean expression.
`Expression`	`setFirstVariableCharacters(java.lang.String chars)` Sets the characters other than letters and digits that are valid as the first character of a variable.
`Expression`	`setPrecision(int precision)` Sets the precision for expression evaluation.
`Expression`	`setRoundingMode(java.math.RoundingMode roundingMode)` Sets the rounding mode for expression evaluation.
`Expression`	`setVariable(java.lang.String variable, java.math.BigDecimal value)` Sets a variable value.
`Expression`	`setVariable(java.lang.String variable, Expression.LazyNumber value)` Sets a variable value.
`Expression`	`setVariable(java.lang.String variable, java.lang.String value)` Sets a variable value.
`Expression`	`setVariableCharacters(java.lang.String chars)` Sets the characters other than letters and digits that are valid as the second and subsequent characters of a variable.
`java.lang.String`	`toRPN()` Get a string representation of the RPN (Reverse Polish Notation) for this expression.
`java.lang.String`	`toString()`
`Expression`	`with(java.lang.String variable, java.math.BigDecimal value)` Sets a variable value.
`Expression`	`with(java.lang.String variable, Expression.LazyNumber value)` Sets a variable value.
`Expression`	`with(java.lang.String variable, java.lang.String value)` Sets a variable value.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - OPERATOR_PRECEDENCE_UNARY
```
public static final int OPERATOR_PRECEDENCE_UNARY
```
    Unary operators precedence: + and - as prefix
    
    See Also:
    
    Constant Field Values
  - OPERATOR_PRECEDENCE_EQUALITY
```
public static final int OPERATOR_PRECEDENCE_EQUALITY
```
    Equality operators precedence: =, ==, !=. <>
    
    See Also:
    
    Constant Field Values
  - OPERATOR_PRECEDENCE_COMPARISON
```
public static final int OPERATOR_PRECEDENCE_COMPARISON
```
    Comparative operators precedence: <,>,<=,>=
    
    See Also:
    
    Constant Field Values
  - OPERATOR_PRECEDENCE_OR
```
public static final int OPERATOR_PRECEDENCE_OR
```
    Or operator precedence: ||
    
    See Also:
    
    Constant Field Values
  - OPERATOR_PRECEDENCE_AND
```
public static final int OPERATOR_PRECEDENCE_AND
```
    And operator precedence: &&
    
    See Also:
    
    Constant Field Values
  - OPERATOR_PRECEDENCE_POWER
```
public static final int OPERATOR_PRECEDENCE_POWER
```
    Power operator precedence: ^
    
    See Also:
    
    Constant Field Values
  - OPERATOR_PRECEDENCE_MULTIPLICATIVE
```
public static final int OPERATOR_PRECEDENCE_MULTIPLICATIVE
```
    Multiplicative operators precedence: *,/,%
    
    See Also:
    
    Constant Field Values
  - OPERATOR_PRECEDENCE_ADDITIVE
```
public static final int OPERATOR_PRECEDENCE_ADDITIVE
```
    Additive operators precedence: + and -
    
    See Also:
    
    Constant Field Values
  - PI
```
public static final java.math.BigDecimal PI
```
    Definition of PI as a constant, can be used in expressions as variable.
  - e
```
public static final java.math.BigDecimal e
```
    Definition of e: "Euler's number" as a constant, can be used in expressions as variable.
- Constructor Detail
  - Expression
```
public Expression(java.lang.String expression)
```
    Creates a new expression instance from an expression string with a given default match context of MathContext.DECIMAL32.
    
    Parameters:
    
    expression - The expression. E.g. "2.4*sin(3)/(2-4)" or "sin(y)>0 & max(z, 3)>3"
  - Expression
```
public Expression(java.lang.String expression,
                  java.math.MathContext defaultMathContext)
```
    Creates a new expression instance from an expression string with a given default match context.
    
    Parameters:
    
    expression - The expression. E.g. "2.4*sin(3)/(2-4)" or "sin(y)>0 & max(z, 3)>3"
    
    defaultMathContext - The MathContext to use by default.
- Method Detail
  - eval
```
public java.lang.Number eval()
```
    Evaluates the expression.
    
    Returns:
    
    The result of the expression. Trailing zeros are stripped.
  - eval
```
public java.lang.Number eval(boolean stripTrailingZeros)
```
    Evaluates the expression.
    
    Parameters:
    
    stripTrailingZeros - If set to true trailing zeros in the result are stripped.
    
    Returns:
    
    The result of the expression.
  - setPrecision
```
public Expression setPrecision(int precision)
```
    Sets the precision for expression evaluation.
    
    Parameters:
    
    precision - The new precision.
    
    Returns:
    
    The expression, allows to chain methods.
  - setRoundingMode
```
public Expression setRoundingMode(java.math.RoundingMode roundingMode)
```
    Sets the rounding mode for expression evaluation.
    
    Parameters:
    
    roundingMode - The new rounding mode.
    
    Returns:
    
    The expression, allows to chain methods.
  - setFirstVariableCharacters
```
public Expression setFirstVariableCharacters(java.lang.String chars)
```
    Sets the characters other than letters and digits that are valid as the first character of a variable.
    
    Parameters:
    
    chars - The new set of variable characters.
    
    Returns:
    
    The expression, allows to chain methods.
  - setVariableCharacters
```
public Expression setVariableCharacters(java.lang.String chars)
```
    Sets the characters other than letters and digits that are valid as the second and subsequent characters of a variable.
    
    Parameters:
    
    chars - The new set of variable characters.
    
    Returns:
    
    The expression, allows to chain methods.
  - addOperator
```
public <OPERATOR extends LazyOperator> OPERATOR addOperator(OPERATOR operator)
```
    Adds an operator to the list of supported operators.
    
    Parameters:
    
    operator - The operator to add.
    
    Returns:
    
    The previous operator with that name, or null if there was none.
  - addFunction
```
public Function addFunction(Function function)
```
    Adds a function to the list of supported functions
    
    Parameters:
    
    function - The function to add.
    
    Returns:
    
    The previous operator with that name, or null if there was none.
  - addLazyFunction
```
public LazyFunction addLazyFunction(LazyFunction function)
```
    Adds a lazy function function to the list of supported functions
    
    Parameters:
    
    function - The function to add.
    
    Returns:
    
    The previous operator with that name, or null if there was none.
  - setVariable
```
public Expression setVariable(java.lang.String variable,
                              java.math.BigDecimal value)
```
    Sets a variable value.
    
    Parameters:
    
    variable - The variable name.
    
    value - The variable value.
    
    Returns:
    
    The expression, allows to chain methods.
  - setVariable
```
public Expression setVariable(java.lang.String variable,
                              Expression.LazyNumber value)
```
    Sets a variable value.
    
    Parameters:
    
    variable - The variable name.
    
    value - The variable value.
    
    Returns:
    
    The expression, allows to chain methods.
  - setVariable
```
public Expression setVariable(java.lang.String variable,
                              java.lang.String value)
```
    Sets a variable value.
    
    Parameters:
    
    variable - The variable to set.
    
    value - The variable value.
    
    Returns:
    
    The expression, allows to chain methods.
  - with
```
public Expression with(java.lang.String variable,
                       java.math.BigDecimal value)
```
    Sets a variable value.
    
    Parameters:
    
    variable - The variable to set.
    
    value - The variable value.
    
    Returns:
    
    The expression, allows to chain methods.
  - with
```
public Expression with(java.lang.String variable,
                       Expression.LazyNumber value)
```
    Sets a variable value.
    
    Parameters:
    
    variable - The variable to set.
    
    value - The variable value.
    
    Returns:
    
    The expression, allows to chain methods.
  - and
```
public Expression and(java.lang.String variable,
                      java.lang.String value)
```
    Sets a variable value.
    
    Parameters:
    
    variable - The variable to set.
    
    value - The variable value.
    
    Returns:
    
    The expression, allows to chain methods.
  - and
```
public Expression and(java.lang.String variable,
                      java.math.BigDecimal value)
```
    Sets a variable value.
    
    Parameters:
    
    variable - The variable to set.
    
    value - The variable value.
    
    Returns:
    
    The expression, allows to chain methods.
  - and
```
public Expression and(java.lang.String variable,
                      Expression.LazyNumber value)
```
    Sets a variable value.
    
    Parameters:
    
    variable - The variable to set.
    
    value - The variable value.
    
    Returns:
    
    The expression, allows to chain methods.
  - with
```
public Expression with(java.lang.String variable,
                       java.lang.String value)
```
    Sets a variable value.
    
    Parameters:
    
    variable - The variable to set.
    
    value - The variable value.
    
    Returns:
    
    The expression, allows to chain methods.
  - getExpressionTokenizer
```
public java.util.Iterator<net.sourceforge.plantuml.evalex.Expression.Token> getExpressionTokenizer()
```
    Get an iterator for this expression, allows iterating over an expression token by token.
    
    Returns:
    
    A new iterator instance for this expression.
  - toRPN
```
public java.lang.String toRPN()
```
    Get a string representation of the RPN (Reverse Polish Notation) for this expression.
    
    Returns:
    
    A string with the RPN representation for this expression.
  - getDeclaredVariables
```
public java.util.Set<java.lang.String> getDeclaredVariables()
```
    Exposing declared variables in the expression.
    
    Returns:
    
    All declared variables.
  - getDeclaredOperators
```
public java.util.Set<java.lang.String> getDeclaredOperators()
```
    Exposing declared operators in the expression.
    
    Returns:
    
    All declared operators.
  - getDeclaredFunctions
```
public java.util.Set<java.lang.String> getDeclaredFunctions()
```
    Exposing declared functions.
    
    Returns:
    
    All declared functions.
  - getExpression
```
public java.lang.String getExpression()
```
    Returns:
    
    The original expression string
  - getUsedVariables
```
public java.util.List<java.lang.String> getUsedVariables()
```
    Returns a list of the variables in the expression.
    
    Returns:
    
    A list of the variable names in this expression.
  - getOriginalExpression
```
public java.lang.String getOriginalExpression()
```
    The original expression used to construct this expression, without variables substituted.
  - equals
```
public boolean equals(java.lang.Object o)
```
    Overrides:
    
    equals in class java.lang.Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - isBoolean
```
public boolean isBoolean()
```
    Checks whether the expression is a boolean expression. An expression is considered a boolean expression, if the last operator or function is boolean. The IF function is handled special. If the third parameter is boolean, then the IF is also considered boolean, else non-boolean.
    
    Returns:
    
    true if the last operator/function was a boolean.

Class Expression

EvalEx - Java Expression Evaluator

Introduction

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

OPERATOR_PRECEDENCE_UNARY

OPERATOR_PRECEDENCE_EQUALITY

OPERATOR_PRECEDENCE_COMPARISON

OPERATOR_PRECEDENCE_OR

OPERATOR_PRECEDENCE_AND

OPERATOR_PRECEDENCE_POWER

OPERATOR_PRECEDENCE_MULTIPLICATIVE

OPERATOR_PRECEDENCE_ADDITIVE

PI

e

Constructor Detail

Expression

Expression

Method Detail

eval

eval

setPrecision

setRoundingMode

setFirstVariableCharacters

setVariableCharacters

addOperator

addFunction

addLazyFunction

setVariable

setVariable

setVariable

with

with

and

and

and

with

getExpressionTokenizer

toRPN

getDeclaredVariables

getDeclaredOperators

getDeclaredFunctions

getExpression

getUsedVariables

getOriginalExpression

equals

hashCode

toString

isBoolean