住宅ローン計算ツール

この住宅ローン計算ツールを使用すると、Java プロパティの値を取得して、Java メソッドのいくつかをその名前を使用して LotusScript から直接呼び出すことができます。

Mortgage.java
public class Mortgage

{

// Java property

public static String F = "Mortgage Calculator";

// Java methods

public double CalculateInterest(float rate, short yr, _

double principal)

   {

 // This bank doesn't bother with compound interest!

 return (rate / 100) * yr * principal;

   }

public double CalculateTotal(double principal, _
   double interest)

   {

 return principal + interest;

   }

public double CalculateMonthlyPayment(float rate, _
  short yr, double principal)

   {

double interest = CalculateInterest(rate, yr, _
    principal);

double total = CalculateTotal(principal, interest);

return total / (yr * 12);

   }

}

Mortgage.lss
Uselsx "*javacon"

Dim mySession As JavaSession

Sub Initialize

Dim myClass As JavaClass

Dim myObject As JavaObject

Dim header As String

Dim rate As Single

Dim yr As Integer

Dim principal As Double, interest As Double

Dim total As Double, monthly_payment As Double

Set mySession = New JavaSession ()

' Set LS values

rate= 8.5

yr= 30

principal= 200000

Set mySession = New JavaSession ()

' Get Java "Mortgage" class

Set myClass = mySession.GetClass("Mortgage;")

' Call Java "Mortgage" Constructor

Set myObject = myClass.CreateObject

' Get Java property (can just use the name)

header = myObject.F

' Call Java Methods (can just use the names)

interest = myObject.CalculateInterest(rate, yr, _
    principal)

total = myObject.CalculateTotal(principal, interest)

monthly_payment = _
    myObject.CalculateMonthlyPayment(rate, yr, principal)

MsgBox { } & header & {

Interest rate:} & rate & {%

Years:            } & 30 & {

Principal:$} & principal & {

Interest:$} & Round(interest, 2) & {

Total:$} & Round(total, 2) & {

Monthly payment:$} & Round(monthly_payment, 2)

End Sub

住宅ローン計算ツール (バージョン 2）

この例では、使用されている構文に次のような問題があります。

• 2 つの Java プロパティ名と 2 つの Java メソッド名が、大文字と小文字が異なるだけになっています。
• その他の 2 つの Java メソッドは多重定義されていて、パラメータ型が異なるだけです。
• 1 つの Java メソッドが 40 文字を超える長さになっています。

Mortgage2.java
public class Mortgage2

{

// Java properties with names that differ only by case

public static String F = "Mortgage Calculator";

public static String f = "from your friendly neighborhood bank";

// Java methods

// Two Java methods with names that differ only by case

public double calculateinterest(float rate, _
  short yr,double principal)

   {

   return rate * yr * principal;

}

public double CalculateInterest(float rate, _
  short yr, double principal)

   {

   return calculateinterest(rate/100, yr, principal);

   }

// Method with a long name

public double

CalculateTotal_with_a_method_name_over_40_characters_long

(double principal, double interest)

   {

   return principal + interest;

   }

// Two Java overloaded methods -- differ only by parameter types

public double CalculateMonthlyPayment(double total, short yr)

   {

   return total / (yr * 12);

   }

public double CalculateMonthlyPayment(float rate, short yr, _

double principal)

   {

 double interest = CalculateInterest(rate, yr, principal);

 double total =

CalculateTotal_with_a_method_name_over_40_characters_long

(principal, interest);

 return CalculateMonthlyPayment(total, yr);

   }

}

Mortgage2.lss
Uselsx "*javacon"

Dim mySession As JavaSession

Sub Initialize

Dim myClass As JavaClass

Dim myObject As JavaObject

Dim myProperty As JavaProperty

Dim myMethod As JavaMethod

Dim myError As JavaError

Dim header1 As String, header2 As String

Dim rate As Single

Dim yr As Integer

Dim principal As Double, interest As Double

Dim total As Double, monthly_payment As Double

Set mySession = New JavaSession ()

' Set LS values

rate= 8.5

yr= 30

principal= 200000

Set mySession = New JavaSession ()

Set myClass = mySession.GetClass("Mortgage2;")

' Call "Mortgage2" constructor

Set myObject = myClass.CreateObject

' Use GetProperty()/GetValue() syntax when

' property names differ only by case

Set myProperty = myClass.GetProperty("F")

header1 = myProperty.GetValue()

Set myProperty = myClass.GetProperty("f")

header2 = myProperty.GetValue()

' Use GetMethod()/Invoke() syntax when method

' names differ only by case

Set myMethod = _
     myClass.GetMethod("CalculateInterest", "(FSD)D")

interest = myMethod.Invoke(myObject, rate, yr, _
     principal)

' or when method name is over 40 characters long

Set myMethod = myClass.GetMethod  _

("CalculateTotal_with_a_method_name_over_40_characters_long", _

 "(DD)D")

total = myMethod.Invoke(myObject, principal, interest)

' or for overloaded Methods (differing only by parameter type)

Set myMethod = _
     myClass.GetMethod("CalculateMonthlyPayment", "(DS)D")

monthly_payment = _
     myObject.CalculateMonthlyPayment(total, yr)

MsgBox { } & header1 & {

} & header2 & {

Interest rate:} & rate & {%

Years:            } & 30 & {

Principal:$} & principal & {

Interest:$} & Round(interest, 2) & {

Total:$} & Round(total, 2) & {

Monthly payment:$} & Round(monthly_payment, 2)

On Error GoTo errhandler

' Throws "java.lang.NoSuchMethodException"

' when user tries to get a method that doesn't exist

Set myMethod = myClass.GetMethod("CalculateTax", _
     "(D)D")

done:

Exit Sub

errhandler:

Set myError = mySession.GetLastJavaError()

MsgBox "JavaError was " & myError.errorMsg

' Clear the Error

mySession.ClearJavaError

Resume done

End Sub

関連項目

LS2J:Java と接続する

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