chuckolet's Blog

오랜만에 자바에서 간단한 파일 입출력을 해보았는데

절대 경로를 불러오는 방법이 생각보다 직관적이지 않았다.

기억해두기 위해 포스팅 하기로 했다.

I found some great website to understand that.


with nice code
Association, Composition and Aggregation in Java

with detailed description
Understanding Association, Aggregation, and Composition


- simplest one
Association Vs Aggregation Vs Composition


In short,

1. Association

  1.1. Association is a relation between two separate classes.
  1.2. Composition and Aggregation are the two forms of association.
  1.3. Association can be one-to-one, one-to-many, many-to-one, many-to-many.
                       
                            pic1. one-to-many association

2. Aggregation 

  2.1. it represents Has-A relationship
  2.2. Each class can have different life cycles.

                        
                           pic2. Aggregation

3. Composition

  3.1. it represents Part-of relationship
  3.2. Each class has same life cycles.



cf)

Aggregation vs Composition

1. Dependency: Aggregation implies a relationship where the child can exist independently of the parent. For example, Bank and Employee, delete the Bank and the Employee still exist. whereas Composition implies a relationship where the child cannot exist independent of the parent. Example: Human and heart, heart don’t exist separate to a Human
2. Type of Relationship: Aggregation relation is “has-a” and composition is “part-of” relation.
3. Type of association: Composition is a strong Association whereas Aggregation is a weak Assocation.

mouseClicked(MouseEvent event)   // Called just after the user clicks the listened-to component.
mouseEntered(MouseEvent event)   // Called just after the cursor enters the bounds of the listened-to component.
mouseExited(MouseEvent event)    // Called just after the cursor exits the bounds of the listened-to component.
mousePressed(MouseEvent event)   // Called just after the user presses a mouse button while the cursor is over the listened-to component.
mouseReleased(MouseEvent event)  // Called just after the user releases a mouse button after a mouse press over the listened-to component

mouseDragged(MouseEvent event)   // Called in response to the user moving the mouse while holding a mouse button down. This event is fired by the component that fired the most recent mouse-pressed event, even if the cursor is no longer over that component.
mouseMoved(MouseEvent event)     // Called in response to the user moving the mouse with no

Add the listeners according to what event you're after.