Introduction to sca

SCA is actually a bit like spring, but SCA injects real services and is about to become an industrial standard. The following is a typical calculator in the demo.

Addition interface:

Package calculator;

/**
* The add Service Interface
*/
Public interface addservice {

Double add (double N1, double N2 );

}

Addition implementation:

Package calculator;

/**
* An Implementation of the add service
*/
Public class addserviceimpl implements addservice {

Public double add (double N1, double N2 ){
Return N1 + N2;
}

}

Subtraction interface:

Package calculator;

/**
* The interface for the multiply Service
*/
Public interface subtractservice {

Double subtract (double N1, double N2 );

}
Implementation of subtraction:

Package calculator;

/**
* An Implementation of the subtract service.
*/
Public class subtractserviceimpl implements subtractservice {

Public double subtract (double N1, double N2 ){
Return N1-N2;
}

}

Multiplication interface:

Package calculator;

/**
* The interface for the multiply Service
*/
Public interface multiplyservice {

Double multiply (double N1, double N2 );

}

Multiplication:

Package calculator;

/**
* An Implementation of the multiply service.
*/
Public class multiplyserviceimpl implements multiplyservice {

Public double multiply (double N1, double N2 ){
Return N1 * N2;
}

}

Division interface:

Package calculator;

/**
* The divide Service Interface
*/
Public interface divideservice {

Double divide (double N1, double N2 );

}

Division implementation:

Package calculator;

/**
* An Implementation of the divide service.
*/
Public class divideserviceimpl implements divideservice {

Public double divide (double N1, double N2 ){
Return N1/N2;
}

}

Calculator Interface

Package calculator;

/**
* The calculator service interface.
*/
Public interface calculatorservice {

Double add (double N1, double N2 );

Double subtract (double N1, double N2 );

Double multiply (double N1, double N2 );

Double divide (double N1, double N2 );

}

Calculator implementation

Package calculator;

Import org. osoa. SCA. Annotations. reference;

/**
* An Implementation of the calculator service.
*/
Public class calculatorserviceimpl implements calculatorservice {

Private addservice;
Private subtractservice;
Private multiplyservice;
Private divideservice;

@ Reference
Public void setaddservice (addservice ){
This. addservice = addservice;
}

@ Reference
Public void setsubtractservice (subtractservice ){
This. subtractservice = subtractservice;
}

@ Reference
Public void setdivideservice (divideservice ){
This. divideservice = divideservice;
}

@ Reference
Public void setmultiplyservice (multiplyservice ){
This. multiplyservice = multiplyservice;
}

Public double add (double N1, double N2 ){
Return addservice. Add (N1, N2 );
}

Public double subtract (double N1, double N2 ){
Return subtractservice. Subtract (N1, N2 );
}

Public double multiply (double N1, double N2 ){
Return multiplyservice. Multiply (N1, N2 );
}

Public double divide (double N1, double N2 ){
Return divideservice. Divide (N1, N2 );
}

}

Calculator. Composite Assembly File

<Composite xmlns = "http://www.osoa.org/xmlns/sca/1.0"
Targetnamespace = "http: // sample"
Xmlns: Sample = "http: // sample"
Name = "Calculator">

<Component name = "calculatorservicecomponent">
<Implementation. Java class = "Calculator. calculatorserviceimpl"/>
<Reference name = "addservice" target = "addservicecomponent"/>
<Reference name = "subtractservice" target = "subtractservicecomponent"/>
<Reference name = "multiplyservice" target = "multiplyservicecomponent"/>
<Reference name = "divideservice" target = "divideservicecomponent"/>
</Component>

<Component name = "addservicecomponent">
<Implementation. Java class = "Calculator. addserviceimpl"/>
</Component>

<Component name = "subtractservicecomponent">
<Implementation. Java class = "Calculator. subtractserviceimpl"/>
</Component>

<Component name = "multiplyservicecomponent">
<Implementation. Java class = "Calculator. multiplyserviceimpl"/>
</Component>

<Component name = "divideservicecomponent">
<Implementation. Java class = "Calculator. divideserviceimpl"/>
</Component>

</Composite>

Client usage

Package calculator;

Import org. Apache. Tuscany. SCA. Host. Embedded. scadomain;

/**
* This client program shows how to create an SCA runtime, start it,
* And locate and invoke a SCA component
*/
Public class calculatorclient {
Public static void main (string [] ARGs) throws exception {

Scadomain = scadomain. newinstance ("Calculator. Composite ");

Calculatorservice =
Scadomain. getservice (calculatorservice. class, "calculatorservicecomponent ");

// Calculate
System. Out. println ("3 + 2 =" + calculatorservice. Add (3, 2 ));
System. Out. println ("3-2 =" + calculatorservice. Subtract (3, 2 ));
System. Out. println ("3*2 =" + calculatorservice. Multiply (3, 2 ));
System. Out. println ("3/2 =" + calculatorservice. Divide (3, 2 ));

Scadomain. Close ();
}

}