Class ClassComparator

  • All Implemented Interfaces:
    java.io.Serializable, java.util.Comparator

    public class ClassComparator
    extends java.lang.Object
    implements java.util.Comparator, java.io.Serializable
    The class comparator can be used to compare and sort classes and their superclasses. The comparator is not able to compare classes which have no relation...
    Author:
    Thomas Morgner
    See Also:
    Serialized Form
    • Constructor Summary

      Constructors 
      Constructor Description
      ClassComparator()
      Defaultconstructor.
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int compare​(java.lang.Object o1, java.lang.Object o2)
      Compares its two arguments for order.
      boolean isComparable​(java.lang.Class c1, java.lang.Class c2)
      Checks, whether the given classes are comparable.
      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
      • Methods inherited from interface java.util.Comparator

        equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong
    • Constructor Detail

      • ClassComparator

        public ClassComparator()
        Defaultconstructor.
    • Method Detail

      • compare

        public int compare​(java.lang.Object o1,
                           java.lang.Object o2)
        Compares its two arguments for order. Returns a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.

        Note: throws ClassCastException if the arguments' types prevent them from being compared by this Comparator. And IllegalArgumentException if the classes share no relation. The implementor must ensure that sgn(compare(x, y)) == -sgn(compare(y, x)) for all x and y. (This implies that compare(x, y) must throw an exception if and only if compare(y, x) throws an exception.)

        The implementor must also ensure that the relation is transitive: ((compare(x, y)>0) && (compare(y, z)>0)) implies compare(x, z)>0.

        Finally, the implementer must ensure that compare(x, y)==0 implies that sgn(compare(x, z))==sgn(compare(y, z)) for all z.

        It is generally the case, but not strictly required that (compare(x, y)==0) == (x.equals(y)). Generally speaking, any comparator that violates this condition should clearly indicate this fact. The recommended language is "Note: this comparator imposes orderings that are inconsistent with equals."

        Specified by:
        compare in interface java.util.Comparator
        Parameters:
        o1 - the first object to be compared.
        o2 - the second object to be compared.
        Returns:
        a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater than the second.
      • isComparable

        public boolean isComparable​(java.lang.Class c1,
                                    java.lang.Class c2)
        Checks, whether the given classes are comparable. This method will return true, if one of the classes is assignable from the other class.
        Parameters:
        c1 - the first class to compare
        c2 - the second class to compare
        Returns:
        true, if the classes share a direct relation, false otherwise.