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compare two objects java

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Innocent Iguana answered on November 27, 2020 Popularity 9/10 Helpfulness 3/10

answer compare two objects java

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public class YourClass{
private int member1;
private int member2;

public YourClass(int member1, int member2){
    this.member1 = member1;
    this.member2 = member2;
}

// You need to override the default equals mthod of Object class
@Override
public boolean equals(Object obj){
    if (this == obj) // if they are the same object
    {
        return true;
    }
    else if (obj instanceof YourClass) { // if they are different objects but members have same value
        var otherObj = (YourClass) obj; // downcast to your class   
        return otherObj.member1 = member1 && otherObj.member2 = member2;
    }
    return false;
    }
}
// Override hash to see whether they are same objects
@Override
public int hashCode(){
    return Objects.hash(member1,member2);
}

public class Main {
    public static void main(String[] args) {
        var a = new YourClass(1,2);
        var b = new YourClass(1,2);

        System.out.println(a.equals(b));
        // Are a and b same object?
        System.out.println(a.hashCode());
        System.out.println(b.hashCode());
    }}

Popularity 9/10 Helpfulness 3/10 Language java

Source: Grepper

Tags: compare java

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Contributed on Aug 08 2023

Innocent Iguana

0 Answers Avg Quality 2/10

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java compare objects

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/*
First, we need a base class that we want to use for comparing.
*/
public class Message{
    private final String content;

    public Message(String content) {
        this.content = content;
    }

    public String getContent() {
        return content;
    }
    
    @Override
    public String toString() {
        return content;
    }
}

/*
Second, we need a class that implements the way we compare objects from our base class.
In this case, we compare objects by the length of the 'content' field.
*/
public class MessageComparator implements Comparator<Message> {
    
    @Override
    public int compare(Message m1, Message m2) {
        int m1Length = m1.getContent().length();
        int m2Length = m2.getContent().length();
        
        return Integer.compare(m1Length, m2Length);
    }
}

/*
Class with main method where we have collection of our base class objects
that we want to compare
*/
public class Main {
    public static void main(String[] args) {
        List<Message> messages = new ArrayList<>();

        messages.add(new Message("Hello"));
        messages.add(new Message("humans!"));
        messages.add(new Message("We"));
        messages.add(new Message("came"));
        messages.add(new Message("in"));
        messages.add(new Message("peace!"));
        
        // Triggers the compare mechanism
        // Will sort by the length of 'content' field
        messages.sort(new MessageComparator());
        
        messages.forEach(System.out::println);
    }
}

/*
TIPS:
If we have more fields in our base class, 
we can create more classes who implements 
Comparator<Message> interface.

In that way, we could compare objects of our base class
by multiple parameters (fields)
*/

Popularity 9/10 Helpfulness 2/10 Language java

Source: Grepper

Tags: compare

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Contributed on Apr 21 2023

0 Answers Avg Quality 2/10

Java compare objects

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//To compare e.g. "Articles" first by their size and than by their title
//we can override compareTo() methond in this way:

@Override
public int compareTo(Article otherArticle) {
    return Comparator.comparing(Article::getSize)
            .thenComparing(Article::getTitle)
            .compare(this, otherArticle);
}

//Other way would be more manual approach:
@Override
public int compareTo(Article otherArticle) {
    int res = Integer.valueOf(getSize()).compareTo(otherArticle.getSize());
    if (res == 0) {
        res = String.valueOf(getTitle()).compareTo(otherArticle.getTitle());
    }

    return res;
}

Popularity 9/10 Helpfulness 2/10 Language java

Source: Grepper

Tags: compare

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Contributed on Feb 21 2023

0 Answers Avg Quality 2/10

how to compare objects in java

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this.equals(other)

Popularity 10/10 Helpfulness 1/10 Language java

Source: Grepper

Tags: compare

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Contributed on Nov 27 2020

Awful Antelope

0 Answers Avg Quality 2/10

compare two objects java

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