com.github.alexmojaki.caseclasses.ComparisonBuilder Maven / Gradle / Ivy

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A framework to refactor computing a result from an aggregate object.

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package com.github.alexmojaki.caseclasses;

import java.util.List;

class ComparisonBuilder extends DualResultBuilder {

    static  int compare(T o1, T o2) {
        ComparisonBuilder builder = new ComparisonBuilder();
        builder.buildResult(o1, o2);
        return builder.result;
    }

    private int result = 0;

    @Override
    protected void extraFirstValue(String name, Object value) {
        throw new ClassCastException("Extra value in first argument with name " + name);
    }

    @Override
    protected void extraSecondValue(String name, Object value) {
        throw new ClassCastException("Extra value in second argument with name " + name);
    }

    private void updateResult(int newResult) {
        if (result == 0) {
            result = newResult;
        }
    }

    @SuppressWarnings("unchecked")
    @Override
    protected void add(String name1, Object value1, String name2, Object value2) {
        if (!name1.equals(name2)) {
            throw new ClassCastException("Differing names: " + name1 + " and " + name2);
        }
        if (value1 == null) {
            throw new NullPointerException("First value with name " + name1 + " is null");
        }
        if (value2 == null) {
            throw new NullPointerException("Second value with name " + name1 + " is null");
        }
        if (value1 instanceof Comparable) {
            updateResult(((Comparable) value1).compareTo(value2));
        } else if (value1 instanceof CaseClass) {
            updateResult(compare(
                    (CaseClass) value1,
                    (CaseClass) value2));
        } else {
            throw new ClassCastException("Couldn't compare values with name " + name1);
        }
    }
}