Android/Java

[Java]  Synchronized

혀가 길지 않은 개발자 2020. 7. 27. 18:35

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

    private String name;
    MainActivity person;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        person = new MainActivity();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=0; i<1000; i++) {
                    person.whoAmI("혀가 길지 않은 개발자");
                }
            }
        }).start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=0; i<1000; i++) {
                    person.whoAmI("혀가 긴 개발자");
                }
            }
        }).start();

    }

    public void whoAmI(String name) {
        try {
            this.name = name;

            long waiting = (long) (Math.random() * 100);
            Thread.sleep(waiting);

            if (!this.name.equals(name)) {
                Log.e("", this.name + " != " + name);
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

실행 결과

 

 

 

 

 

 

 

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

    private String name;
    MainActivity person;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        person = new MainActivity();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=0; i<1000; i++) {
                    person.whoAmI("혀가 길지 않은 개발자");
                }
            }
        }).start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=0; i<1000; i++) {
                    person.whoAmI("혀가 긴 개발자");
                }
            }
        }).start();

    }

    public synchronized void whoAmI(String name) {
        try {
            this.name = name;

            long waiting = (long) (Math.random() * 100);
            Thread.sleep(waiting);

            if (!this.name.equals(name)) {
                Log.e("", this.name + " != " + name);
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

public void whoAmI(String name) 에서

public synchronized void whoAmI(String name) 로 수정

 

실행 결과

 

 

 

 

 

 

 

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

    private String food;
    MainActivity person;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        person = new MainActivity();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=0; i<1000; i++) {
                    person.eatPizza();
                }
            }
        }).start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=0; i<1000; i++) {
                    person.eatHamburger();
                }
            }
        }).start();

    }


    public void eatPizza() {
        try {
            this.food = "Pizza";

            long waiting = (long) (Math.random() * 100);
            Thread.sleep(waiting);

            if (!this.food.equals("Pizza")) {
                Log.e("", this.food + " != Pizza");
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void eatHamburger() {
        try {
            this.food = "Hamburger";

            long waiting = (long) (Math.random() * 100);
            Thread.sleep(waiting);

            if (!this.food.equals("Hamburger")) {
                Log.e("", this.food + " != Hamburger");
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

실행 결과

 

 

 

 

 

 

 

 

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

    private String food;
    MainActivity person;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        person = new MainActivity();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=0; i<1000; i++) {
                    person.eatPizza();
                }
            }
        }).start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=0; i<1000; i++) {
                    person.eatHamburger();
                }
            }
        }).start();

    }


    public synchronized void eatPizza() {
        try {
            this.food = "Pizza";

            long waiting = (long) Math.random() * 100;
            Thread.sleep(waiting);

            if (!this.food.equals("Pizza")) {
                Log.e("", this.food + " != Pizza");
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public synchronized void eatHamburger() {
        try {
            this.food = "Hamburger";

            long waiting = (long) Math.random() * 100;
            Thread.sleep(waiting);

            if (!this.food.equals("Hamburger")) {
                Log.e("", this.food + " != Hamburger");
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

synchronized 추가

 

실행 결과

 

 

 

 

 

 

 

 

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

    private String food;
    MainActivity person1;
    MainActivity person2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        person1 = new MainActivity();
        person2 = new MainActivity();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=0; i<1000; i++) {
                    person1.eatPizza();
                }
            }
        }).start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=0; i<1000; i++) {
                    person2.eatHamburger();
                }
            }
        }).start();

    }


    public void eatPizza() {
        try {
            this.food = "Pizza";

            long waiting = (long) Math.random() * 100;
            Thread.sleep(waiting);

            if (!this.food.equals("Pizza")) {
                Log.e("", this.food + " != Pizza");
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void eatHamburger() {
        try {
            this.food = "Hamburger";

            long waiting = (long) Math.random() * 100;
            Thread.sleep(waiting);

            if (!this.food.equals("Hamburger")) {
                Log.e("", this.food + " != Hamburger");
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

객체 2개 생성

MainActivity person1;

MainActivity person2;

 

실행 결과

 

 

 

 

 

 

 

 

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private List<Integer> list;
    private int tryCount = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        list = new ArrayList<>();

        Log.e("", "start!");

        Thread thread1 = new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=1; i<=10000; i++) {
                    pushNumber(i);
                }
            }
        });

        thread1.start();

        Thread thread2 = new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=1; i<=10000; i++) {
                    pushNumber(i);
                }
            }
        });

        thread2.start();

        try {
            thread1.join();
            thread2.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        Log.e("", "End! " + list.size());
    }

    void pushNumber(int number) {
        Log.e("", Integer.toString(tryCount++));

        if (!list.contains(number)) {
            list.add(number);
        }
    }

}

카운트 총합이 20000미만인 이유는 첫 번째 스레드가 49에서 50으로 증가하는 타이밍에 두 번째 스레드에서 48에서 49로 증가하게 되면 카운트 총합은 감소하게 된다.

 

실행 결과

 

 

 

 

 

 

 

 

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private List<Integer> list;
    private int tryCount = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        list = new ArrayList<>();

        Log.e("", "start!");

        Thread thread1 = new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=1; i<=10000; i++) {
                    pushNumber(i);
                }
            }
        });

        thread1.start();

        Thread thread2 = new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=1; i<=10000; i++) {
                    pushNumber(i);
                }
            }
        });

        thread2.start();

        try {
            thread1.join();
            thread2.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        Log.e("", "End! " + list.size());
    }

    void pushNumber(int number) {
        Log.e("", Integer.toString(tryCount++));

        synchronized (this) {
            if (!list.contains(number)) {
                list.add(number);
            }
        }
    }

}

실행 결과

 

 

 

 

 

 

 

 

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    int count1 = 0;
    int count2 = 0;
    MainActivity stopWatch;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        stopWatch = new MainActivity();

        Long startTime = System.currentTimeMillis();

        Thread thread1 = new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=1; i<=10000; i++) {
                    stopWatch.addCount1();
                }
            }
        });

        Thread thread2 = new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=1; i<=10000; i++) {
                    stopWatch.addCount2();
                }
            }
        });

        thread1.start();
        thread2.start();

        try {
            thread1.join();
            thread2.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        Long endTime = System.currentTimeMillis();
        Long elapsedTime = endTime - startTime;
        Log.e("소요시간 : ", Long.toString(elapsedTime));

    }

    public synchronized void addCount1() {
        Log.e("", "count1 : " + this.count1++);
    }

    public synchronized void addCount2() {
        Log.e("", "count2 : " + this.count2++);
    }

}

실행 결과

 

 

 

 

 

 

 

 

MainActivity.java

package com.jwsoft.javaproject;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

    int count1 = 0;
    int count2 = 0;
    MainActivity stopWatch;

    private final Object object1 = new Object();
    private final Object object2 = new Object();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        stopWatch = new MainActivity();

        Long startTime = System.currentTimeMillis();

        Thread thread1 = new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=1; i<=10000; i++) {
                    stopWatch.addCount1();
                }
            }
        });

        Thread thread2 = new Thread(new Runnable() {
            @Override
            public void run() {
                for (int i=1; i<=10000; i++) {
                    stopWatch.addCount2();
                }
            }
        });

        thread1.start();
        thread2.start();

        try {
            thread1.join();
            thread2.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        Long endTime = System.currentTimeMillis();
        Long elapsedTime = endTime - startTime;
        Log.e("소요시간 : ", Long.toString(elapsedTime));

    }

    public void addCount1() {
        synchronized (object1) {
            Log.e("", "count1 : " + this.count1++);
        }
    }

    public void addCount2() {
        synchronized (object2) {
            Log.e("", "count2 : " + this.count2++);
        }
    }

}

synchronized (object1) 로 수정

synchronized (object2) 로 수정

위의 경우보다 효율이 좋음

 

실행 결과

 

 

 

 

 

 

저작자표시 (새창열림)