Java/Mode Selection Performance Test

1. if-else ¶

�� .

~cpp 
public class IfElse {
    public void printPerformance(String[] modeExecute) {
        long start;
        long end;
        start = System.currentTimeMillis();
        for (int i = 0; i < ModeChoicePerformanceTest.LOOPING_COUNT; i++) {
            executeIfElse(modeExecute);
        }
        end = System.currentTimeMillis();
        System.out.println("if - else elapsed time :" + (end - start) + "ms ");
    }

    private void executeIfElse(String[] modeExecute) {
        for (int i = 0; i < modeExecute.length; i++) {
            executeWithIfElse(modeExecute[i]);
        }
    }

    public void executeWithIfElse(String mode) {
        if (mode.equals("One")) {
            doOne(1);
        } else if (mode.equals("Two")) {
            doTwo(1);
        } else if (mode.equals("Three")) {
            doThree(1);
        } else if (mode.equals("Four")) {
            doFour(1);
        } else if (mode.equals("Five")) {
            doFive(1);
        } else {
            doDefault(1);
        }
    }


    public void doOne(int i) {
        i = 10;
    }

    public void doTwo(int i) {
        i = 10;
    }

    public void doThree(int i) {
        i = 10;
    }

    public void doFour(int i) {
        i = 10;
    }

    public void doFive(int i) {
        i = 10;
    }

    public void doDefault(int i) {
        i = 100;
    }
}

�� . 하��, 한편��

WhySwitchStatementsAreBadSmell�� ? ��.. �� 한 �� '�� mode �� Switch-Statement �� 황 ��. �� 해�� 행�� .' �� 할��. ��. ��.
한편�� , switch �� mode string �� parameter �� . �� 하�� mode �� 해�� method �� , mode string �� , if-else �� . �� 해�� 황��, �� ? �� 한�� 할�� . (��, �� 한해��) GotoStatementConsideredHarmful.

�� - Method reflection ¶

~cpp 

import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;

public class MethodFullReflection {
    public void printPerformance(String[] modeExecute) throws InvocationTargetException, IllegalAccessException {
        long start;
        long end;
        start = System.currentTimeMillis();
        for (int i = 0; i < ModeChoicePerformanceTest.LOOPING_COUNT; i++) {
            executeReflection(modeExecute);
        }
        end = System.currentTimeMillis();
        System.out.println("elapsed time :" + (end - start) + "ms ");

    }

    private void executeReflection(String[] modeExecute) throws InvocationTargetException, IllegalAccessException {
        for (int i = 0; i < modeExecute.length; i++) {
            Method method = null;
            try {
                method = this.getClass().getMethod("do" + modeExecute[i], new Class[]{int.class});
                method.invoke(this, new Object[]{new Integer(1)});
            } catch (NoSuchMethodException e) {
                this.doDefault(1);
            } catch (SecurityException e) {
                e.printStackTrace();  //To change body of catch statement use Options | File Templates.
            }
        }
    }

    private void doDefault(int i) {
        i = 100;
    }

    public void doOne(int i) {
        i = 10;
    }

    public void doTwo(int i) {
        i = 10;
    }

    public void doThree(int i) {
        i = 10;
    }

    public void doFour(int i) {
        i = 10;
    }

    public void doFive(int i) {
        i = 10;
    }

}

�� : MODE �� doXXX �� 해�� 행하�� . �� , 해�� Mode �� 하�� 해�� .
�� : �� Method Reflection & Invoke �� .; �� .

��. �� 한 ��. �� Table Lookup. ¶

~cpp 

import java.util.HashMap;
import java.util.Map;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;

/**
 * User: Administrator Date: 2003. 7. 12. Time: ������ 12:48:38
 */
public class MethodTableLookupReflection {
    public void printPerformance(String[] modeExecute) throws InvocationTargetException, IllegalAccessException {
        long start;
        long end;
        start = System.currentTimeMillis();
        initReflectionMap(modeExecute);
        end = System.currentTimeMillis();
        System.out.println("reflection with method initialize table elapsed time :" + (end - start) + "ms ");

        start = System.currentTimeMillis();
        for (int i = 0; i < ModeChoicePerformanceTest.LOOPING_COUNT; i++) {
            executeReflectionWithMapping(modeExecute);
        }
        end = System.currentTimeMillis();
        System.out.println("reflection with method elapsed time :" + (end - start) + "ms ");

    }

    private static Map methodMap;


    private void executeReflectionWithMapping(String[] modeExecute) throws InvocationTargetException, IllegalAccessException {
        for (int i = 0; i < modeExecute.length; i++) {
            Method method = (Method) methodMap.get(modeExecute[i]);
            if (method != null)
                method.invoke(this, new Object[]{new Integer(1)});
            else
                doDefault(1);
        }
    }

    private void initReflectionMap(String[] methodNames) {
        methodMap = new HashMap();
        for (int i = 0; i < methodNames.length; i++) {
            try {
                methodMap.put(methodNames[i], this.getClass().getMethod("do" + methodNames[i], new Class[]{int.class}));
            } catch (NoSuchMethodException e) {
            } catch (SecurityException e) {
            }
        }

    }

    private void doDefault(int i) {
        i = 100;
    }

    public void doOne(int i) {
        i = 10;
    }

    public void doTwo(int i) {
        i = 10;
    }

    public void doThree(int i) {
        i = 10;
    }

    public void doFour(int i) {
        i = 10;
    }

    public void doFive(int i) {
        i = 10;
    }
}

�� 포�� 10�� 향��킨��.

��. Inner Class �� 해 Command Pattern �� . ¶

~cpp 

import java.util.Map;
import java.util.HashMap;

/**
 * User: Administrator Date: 2003. 7. 12. Time: ������ 12:57:7
 */
public class InterfaceTableLookup {
    protected Map modeMap = new HashMap();

    public void printPerformance(String[] modeExecute) {
        long start;
        long end;
        start = System.currentTimeMillis();
        initModeMap();
        end = System.currentTimeMillis();
        System.out.println("interface table lookup init table elapsed time :" + (end - start) + "ms ");

        start = System.currentTimeMillis();
        for (int i = 0; i < ModeChoicePerformanceTest.LOOPING_COUNT; i++) {
            executeInnerclassMapping(modeExecute);
        }
        end = System.currentTimeMillis();
        System.out.println("interface table lookup elapsed time :" + (end - start) + "ms ");


    }

    private void executeInnerclassMapping(String[] modeExecute) {
        for (int i = 0; i < modeExecute.length; i++) {
            executeMode(modeExecute[i]);
         }
    }

    private void executeMode(String s) {
        IMode mode = (IMode) modeMap.get(s);
        if (mode == null) doDefault(1);
        else mode.execute(1);
    }

    public class ExOne implements IMode {
        public void execute(int i) {
            i = 10;
        }
    }

    public  class ExTwo implements IMode {
        public void execute(int i) {
            i = 10;
        }
    }

    public class ExThree implements IMode {
        public void execute(int i) {
            i = 10;
        }
    }

    public class ExFour implements IMode {
        public void execute(int i) {
            i = 10;
        }
    }

    public class ExFive implements IMode {
        public void execute(int i) {
            i = 10;
        }
    }

    private void initModeMap() {
        modeMap.put("One", new ExOne());
        modeMap.put("Two", new ExTwo());
        modeMap.put("Three", new ExThree());
        modeMap.put("Four", new ExFour());
        modeMap.put("Five", new ExFive());
    }
}

�� initModeMap �� Mode�� 한 �� 해�� 한��. ��포�� Method Reflection �� 훨�� .

�� - interface & reflection ¶

�� initModeMap �� reflection �� 한 ��.

~cpp 
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;

/**
 * User: Administrator Date: 2003. 7. 12. Time: ������ 1:2:16
 */
public class InterfaceTableLookupReflection {
    public void printPerformance(String[] modeExecute) throws NoSuchMethodException, InstantiationException, ClassNotFoundException, InvocationTargetException, IllegalAccessException {
        long start;
        long end;
        start = System.currentTimeMillis();
        initModeMapWithReflection(modeExecute);
        end = System.currentTimeMillis();
        System.out.println("interface reflection & table lookup init able elapsed time :" + (end - start) + "ms ");

        start = System.currentTimeMillis();
        for (int i = 0; i < ModeChoicePerformanceTest.LOOPING_COUNT; i++) {
            executeInnerclassMapping(modeExecute);
        }
        end = System.currentTimeMillis();
        System.out.println("interface reflection & table lookup elapsed time :" + (end - start) + "ms ");

    }

    private void executeInnerclassMapping(String[] modeExecute) {
        for (int i = 0; i < modeExecute.length; i++) {
            executeMode(modeExecute[i]);
         }
    }

    private void executeMode(String s) {
        IMode mode = (IMode) modeMap.get(s);
        if (mode == null) doDefault(1);
        else mode.execute(1);
    }

    protected Map modeMap = new HashMap();
    public final static String modeClassHeader = "Ex";
    String expectedClassNameHeader = this.getClass().getName() + "$" + modeClassHeader;

    private void initModeMapWithReflection(String[] modeExecute) throws InstantiationException, InvocationTargetException, IllegalAccessException, NoSuchMethodException {
        Class[] consParamClasses = new Class[]{this.getClass()};
        Object[] consParams = new Object[]{this};


        Class[] inners = this.getClass().getClasses();
        for (int i=0;i<inners.length;i++) {
            if (inners[i].getName().startsWith(expectedClassNameHeader)) {
                Constructor innerCons = inners[i].getDeclaredConstructor(consParamClasses);
                modeMap.put(modeExecute[i], innerCons.newInstance(consParams));
            }
        }
    }

    public void doDefault(int i) {
        i = 100;
    }

    public class ExOne implements IMode {
        public void execute(int i) {
            i = 10;
        }
    }

    public  class ExTwo implements IMode {
        public void execute(int i) {
            i = 10;
        }
    }

    public class ExThree implements IMode {
        public void execute(int i) {
            i = 10;
        }
    }

    public class ExFour implements IMode {
        public void execute(int i) {
            i = 10;
        }
    }

    public class ExFive implements IMode {
        public void execute(int i) {
            i = 10;
        }
    }
}

�� Mode �� ExModeName �� 해�� . �� Mode �� 하�� . Reflection�� table lookup �� Mode �� 클�� 할 �� . ��포�� map �� . �� 포�� 히 �� .

�� 테��트�� 한�� 행��키�� 한 runner class.

~cpp 
import java.lang.reflect.InvocationTargetException;

/*
  평���하������ ��������� :
  1. 해��� method ��� naming ������ reflection call.
  2. switch - case ��� mode ������.
  3. interface & class - command pattern ��� �����.

  평������������
  1. 해��� ������ ������������ ������������ ������ ���������
  2. performance
  3. maintance
*/
public class ModeChoicePerformanceTest {
    public static final int LOOPING_COUNT = 1000000;

    public static void main(String[] args) throws NoSuchMethodException, IllegalAccessException, InvocationTargetException, ClassNotFoundException, InstantiationException {
        String[] modeExecute = new String[]{"One", "Two", "Three", "Four", "Five", "hugu"};

        new IfElse().printPerformance(modeExecute);
        new MethodFullReflection().printPerformance(modeExecute);
        new MethodTableLookupReflection().printPerformance(modeExecute);
        new InterfaceTableLookup().printPerformance(modeExecute);
        new InterfaceTableLookupReflection().printPerformance(modeExecute);
    }
}

�� ¶

~cpp 
if - else elapsed time :611ms 
elapsed time :61889ms 
reflection with method initialize table elapsed time :0ms 
reflection with method elapsed time :6459ms 
interface table lookup init table elapsed time :10ms 
interface table lookup elapsed time :741ms 
interface reflection & table lookup init able elapsed time :10ms 
interface reflection & table lookup elapsed time :731ms

Java

Java/Mode Selection Performance Test

1. if-else ¶

��������� - Method reflection ¶

���������. ������ ��������� ������한 ������������. ������ ��������� Table Lookup. ¶

���������. Inner Class ��� ���해 Command Pattern ��� ������. ¶

��������� ������ - interface & reflection ¶

������ ¶

�� - Method reflection ¶

��. �� 한 ��. �� Table Lookup. ¶

��. Inner Class �� 해 Command Pattern �� . ¶

�� - interface & reflection ¶

�� ¶