com.ds.common.expression.function

类 Function

java.lang.Object

com.ds.common.expression.function.Function

所有已实现的接口:

FunctionI

直接已知子类:

AbstractFunction, Add, Comparative, DefaultFunction, Divide, GetClientService, IIf, Logical, Modulus, Multiply, Not, Power, Subtract, UMinus

public abstract class Function
extends Object
implements FunctionI

Function classes extend this class. It is an implementation of the FunctionI interface.

It includes a numberOfParameters member, that is checked when parsing the expression. This member should be initialized to an appropriate value for all classes extending this class. If an arbitrary number of parameters should be allowed, initialize this member to -1.

字段概要

字段

限定符和类型	字段和说明
protected int	curNumberOfParameters Number of parameters to be used for the next run() invocation.
protected int	numberOfParameters Number of parameters a the function requires.

构造器概要

构造器

构造器和说明
Function() Creates a new PostfixMathCommand class.

方法概要

限定符和类型	方法和说明
protected void	checkStack(Stack inStack) Check whether the stack is not null, throw a ParseException if it is.
int	getNumberOfParameters() Return the required number of parameters.
abstract void	run(Stack s) Throws an exception because this method should never be called under normal circumstances.
void	setCurNumberOfParameters(int n) Sets the number of current number of parameters used in the next call of run().

从类继承的方法 java.lang.Object

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

字段详细资料

numberOfParameters

protected int numberOfParameters

Number of parameters a the function requires. Initialize this value to -1 if any number of parameters should be allowed.

curNumberOfParameters

protected int curNumberOfParameters

Number of parameters to be used for the next run() invocation. Applies only if the required umber of parameters is variable (numberOfParameters = -1).

构造器详细资料

Function

public Function()

Creates a new PostfixMathCommand class.

方法详细资料

checkStack

protected void checkStack(Stack inStack)
                   throws ParseException

Check whether the stack is not null, throw a ParseException if it is.

抛出:

ParseException

getNumberOfParameters

public int getNumberOfParameters()

Return the required number of parameters.

指定者:

getNumberOfParameters 在接口中 FunctionI

setCurNumberOfParameters

public void setCurNumberOfParameters(int n)

Sets the number of current number of parameters used in the next call of run(). This method is only called when the reqNumberOfParameters is -1.

指定者:

setCurNumberOfParameters 在接口中 FunctionI

run

public abstract void run(Stack s)
                  throws ParseException

Throws an exception because this method should never be called under normal circumstances. Each function should use it's own run() method for evaluating the function. This includes popping off the parameters from the stack, and pushing the result back on the stack.

指定者:

run 在接口中 FunctionI

抛出:

ParseException