How to use Builder pattern as described by Joshua Bloch's version in my ModelInput class?

Question

I am trying to use Builder Pattern for my below class.. Initially I was using constructor of my class to set all the parameters but accidentally I came across Builder pattern an

Answer 1

I am not familiar with the book you are referencing, but I would suggest reading the post of wikipedia regarding the Builder pattern which is rather straight forward.

An implementation could be:

public final class ModelInput {

...

    public static class Builder {
        private long userid;
        ...    

        public Builder(long userid) {
            this.userid = userid;
        }

       ...

        public ModelInput build() {
            return new ModelInput(this);
        }
    }

    private ModelInput(Builder builder){
        this.userid = builder.userid;
        this.clientid = builder.clientid;
        this.pref = builder.pref;
        this.parameterMap = builder.parameterMap;
        this.timeout = builder.timeout;
        this.debug = builder.debug;
    }

...
}

Then when you want to initialize an object, you would call

ModelInput model = new ModelInput.Builder(...).build();

Regarding the validation process, it would be essentially the same as it would be made by checking the values (either in the constructor, or in the build method).

Hope I helped!