Описание тега comparable

In Java, this interface is implemented by a class to indicate that it can be compared to another object and therefore ordered. The interface defines one method: compareTo(). Classes can either implement it as a raw type, as with older versions of Java:

public class MyClass implements Comparable
{
    public int compareTo(Object other)
    {
        MyClass toCompare = (MyClass) other;
        //...
    }
}

Or, as of Java 1.5, a class can use generics:

public class MyClass implements Comparable<MyClass>
{
    public int compareTo(MyClass other)
    {
        //...
    }
}

The general contract of compareTo() is:

• If this is less than the parameter, it returns a value less than zero.
• If this is greater than the parameter, it returns a value greater than zero.
• Otherwise, if this is equal to the parameter, returns zero.

The actual value of compareTo() is irrelevant; only the sign of the return value matters.

Javadoc for java.lang.Comparable