Is it possible to make eclipse generate hashCode and equals with HashCodeBuilder and EqualsBuilder

Question

The default generated hashCode and equals implementations are ugly at best.

Is it possible to make eclipse generate ones from HashCodeBuilder and EqualsBuilder, and perhaps even a toString with ToStringBuilder?

Answer 1

Take a look at Commons4E

It hasn't been updated in a while, but then I don't guess it needs to change much?

Update: Just checked against 3.4.1 and it works fine.

Answer 2

You can configure Eclipse to generate toString() using a custom builder. In our case ToStringBuilder from Apache Commons Lang. You can see here http://azagorneanu.blogspot.com/2011/08/how-to-generate-equals-hashcode.html how to do it.

That blog post contains also Eclipse templates for generating equals(), hashCode() and compareTo() using Apache Commons Lang builders.

Answer 3

You can do that with Code Templates in Eclipse.

Here's a solution that I found with examples of HashCodeBuilder and EqualsBuilder.

Template EqualsBuilder:

    public boolean equals(Object o) {
        boolean result = false;

        if (this == o) {
            result = true;
        } else if (o instanceof $CLASSNAME$) {
            $CLASSNAME$ other = ($CLASSNAME$) o;

            result = new org.apache.commons.lang.builder.EqualsBuilder()
                    .append($END$
                    .isEquals();
        }

        return result;
    }

Template HashCodeBuilder:

    public int hashCode() {
        return new org.apache.commons.lang.builder.HashCodeBuilder()
                .append( $END$ )
                .toHashCode();
    }

Answer 4

I use the Eclipse plugin called "Commonclipse"

After installation, you see a new context menu item "commonclipse" when you right click within a java source file. It can generate equals, hashcode, toString and compareTo methods based on the Apache commons libraries.

To install it, use this from within eclipse update: http://commonclipse.sourceforge.net

Answer 5

I made this template checking several answers, websites and testing it on Eclipse Luna. Go to Windows->Preferences and then to Java->Editor->Templates and add it there.

${:import(org.apache.commons.lang3.builder.HashCodeBuilder, org.apache.commons.lang3.builder.EqualsBuilder)}
@Override
public int hashCode() {
    HashCodeBuilder hashCodeBuilder = new HashCodeBuilder();
    hashCodeBuilder.append(${field1:field});
    hashCodeBuilder.append(${field2:field});
    hashCodeBuilder.append(${field3:field});
    hashCodeBuilder.append(${field4:field});
    hashCodeBuilder.append(${field5:field});
    return hashCodeBuilder.toHashCode();
}

@Override
public boolean equals(Object obj) {
    if (this == obj) {
        return true;
    }
    if (obj == null) {
        return false;
    }
    if (getClass() != obj.getClass()) {
        return false;
    }
    ${enclosing_type} rhs = (${enclosing_type}) obj;
    EqualsBuilder equalsBuilder = new EqualsBuilder();
    equalsBuilder.append(${field1}, rhs.${field1});
    equalsBuilder.append(${field2}, rhs.${field2});
    equalsBuilder.append(${field3}, rhs.${field3});
    equalsBuilder.append(${field4}, rhs.${field4});
    equalsBuilder.append(${field5}, rhs.${field5});${cursor}
    return equalsBuilder.isEquals();
}

Answer 6

Eclipse java code templates for eclipse 3.5.0, derived from Bruno Conde's templates:

@Override
public boolean equals(Object obj) {
    if (obj == null) {
        return false;
    } else if (obj == this) {
        return true;
    } else if (obj.getClass() != this.getClass()) {
        return false;
    }

    ${enclosing_type} other = (${enclosing_type}) obj;
    return new EqualsBuilder()//
            .appendSuper(super.equals(other))//
            .append(${cursor})//
                .isEquals();
}

and

@Override
public int hashCode() {
    return new HashCodeBuilder(${cursor})//
            .append()//
            .toHashCode();
}