BuboFlash - helps with learning

Do you want BuboFlash to help you learning these things? Or do you want to add or correct something? Click here to log in or create user.

Presentation
Question

Answer

Tags

#bloch-effective-java-2ed #equality #java

Question

Suppose we have a class


public class Point {
    private final int x;
    private final int y;

    @Override public boolean equals(Object o) {
	if (!(o instanceof Point))
	    return false;
	Point p = (Point)o;
	return p.x == x && p.y == y;
    }
    // Remainder omitted
}

and a subclass

public class ColorPoint extends Point {
    private final Color color;
    // Remainder omitted
}

what are the consequences of NOT implementing equals() method on ColorPoint?

Answer

equals() contract is not violated, but all color information is ignored in equality comparisons

Tags

#bloch-effective-java-2ed #equality #java

Question

Suppose we have a class


public class Point {
    private final int x;
    private final int y;

    @Override public boolean equals(Object o) {
	if (!(o instanceof Point))
	    return false;
	Point p = (Point)o;
	return p.x == x && p.y == y;
    }
    // Remainder omitted
}

and a subclass

public class ColorPoint extends Point {
    private final Color color;
    // Remainder omitted
}

what are the consequences of NOT implementing equals() method on ColorPoint?

Answer

Tags

#bloch-effective-java-2ed #equality #java

Question

Suppose we have a class


public class Point {
    private final int x;
    private final int y;

    @Override public boolean equals(Object o) {
	if (!(o instanceof Point))
	    return false;
	Point p = (Point)o;
	return p.x == x && p.y == y;
    }
    // Remainder omitted
}

and a subclass

public class ColorPoint extends Point {
    private final Color color;
    // Remainder omitted
}

what are the consequences of NOT implementing equals() method on ColorPoint?

Answer

equals() contract is not violated, but all color information is ignored in equality comparisons

If you want to change selection, open document below and click on "Move attachment"

pdfs

owner: piotr.wasik - (no access) - Effective Java (Joshua Bloch), 2ed, p37
owner: Jack-Rustier - (no access) - Joshua Bloch-Effective Java-Addison-Wesley (2017).pdf, p62

Summary

status	not learned	measured difficulty	37% [default]	last interval [days]
repetition number in this series	0	memorised on		scheduled repetition
scheduled repetition interval		last repetition or drill

Details

No repetitions

Discussion

Do you want to join discussion? Click here to log in or create user.