Package com.singularsys.jep.functions.strings

Class Substring

java.lang.Object

com.singularsys.jep.functions.PostfixMathCommand

com.singularsys.jep.functions.NaryFunction

com.singularsys.jep.functions.strings.Substring

All Implemented Interfaces:

PostfixMathCommandI, Serializable

public class Substring
extends NaryFunction

Extract substring of first argument: substring("abcdefg",2,4) -> "cd". Syntax substring(str,start,[end]). Second argument is starting index, third argument is optional, if not present return rest of string if present third argument is the ending index, exclusive. Note that the indices are zero-based.

• If start is greater than the length of the string an EvaluationException is thrown.
• If start is less than zero an EvaluationException is thrown.
• If end is less than start an EvaluationException is thrown.
• If end is greater than the length of the string an EvaluationException is thrown.
• If str is not a string an EvaluationException is thrown.
• If start is not a number representing an integer an EvaluationException is thrown.
• If end is not a number representing an integer an EvaluationException is thrown.

See Also:

• String.substring(int, int)
• Serialized Form

Field Summary

Fields inherited from class com.singularsys.jep.functions.PostfixMathCommand

curNumberOfParameters, name, NaN, numberOfParameters

Constructor Summary

Constructors

Constructor	Description
Substring()

Method Summary

Modifier and Type	Method	Description
boolean	checkNumberOfParameters(int n)	Checks the number of parameters of the function.
Object	eval(Object[] args)	Evaluate the function

Methods inherited from class com.singularsys.jep.functions.NaryFunction

run

Methods inherited from class com.singularsys.jep.functions.PostfixMathCommand

asArray, asBool, asDouble, asInt, asLong, asStrictInt, asString, getName, getNumberOfParameters, setCurNumberOfParameters, setName, toString, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

Substring

public Substring()

Method Details

checkNumberOfParameters

public boolean checkNumberOfParameters(int n)

Description copied from class: PostfixMathCommand

Checks the number of parameters of the function. Functions which set numberOfParameter=-1 should overload this method

Specified by:

checkNumberOfParameters in interface PostfixMathCommandI

Overrides:

checkNumberOfParameters in class PostfixMathCommand

Parameters:

n - number of parameters function will be called with.

Returns:

false if an illegal number of parameters is supplied, true otherwise.

eval

public Object eval(Object[] args)
            throws EvaluationException

Description copied from class: NaryFunction

Evaluate the function

Specified by:

eval in class NaryFunction

Parameters:

args - arguments to the function

Returns:

value returned by the function

Throws:

EvaluationException - if the calculation cannot be performed