59 lines
2.1 KiB
Java
59 lines
2.1 KiB
Java
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/*
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* ElemComparator.java 2004-11-05
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*
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* Dirk Ansorge, FernUniversitaet Hagen
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*
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*/
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package twodsack.util.comparator;
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import twodsack.setelement.*;
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import twodsack.setelement.datatype.*;
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import twodsack.util.collectiontype.*;
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import java.io.Serializable;
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import java.util.Comparator;
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/**
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* This class is derived from the original {@link java.util.Comparator} class. It is still an ordinary
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* comparator, but works only for pairs of type {@link twodsack.setelement.Element}. Therefore, the original
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* <code>compare</code> method is overwritten. To be precise, this comparator doesn't work on
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* pairs of type <code>Element</code> directly, but on such types wrapped in objects of type
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* {@link twodsack.util.collectiontype.MultiSetEntry}. Usually, they can be found in a
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* {@link twodsack.set.ElemMultiSet} structure.
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*/
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public class ElemComparator implements Comparator,Serializable {
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/*
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* constructors
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*/
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/**
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* Constructs an 'empty' instance.
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*/
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public ElemComparator(){}
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/*
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* methods
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*/
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/**
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* Compares two objects which must be of type <code>MultiSetEntry</code>.
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* The objects wrapped inside of <code>ino1</code> and <code>ino2</code> must be of the same
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* <i>subtype</i> of {@link twodsack.setelement.Element} in this case, e.g. both of type
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* {@link twodsack.setelement.datatype.basicdatatype.Point}. The return value
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* is 0 if both elements are equal, -1 if <code>ino1</code> is smaller than <code>ino2</code>
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* and 1 otherwise.
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*
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* @param ino1 the first object
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* @param ino2 the second object
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* @return {0,-1,1} depending on the objects
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*/
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public int compare(Object ino1, Object ino2) {
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if ((((MultiSetEntry)ino1).value instanceof Element) &&
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(((MultiSetEntry)ino2).value instanceof Element))
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return ((Element)((MultiSetEntry)ino1).value).compare((Element)((MultiSetEntry)ino2).value);
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else
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throw new WrongTypeException("in ElemComparator: Expected Element - found: "+(((MultiSetEntry)ino1).value.getClass())+"/"+(((MultiSetEntry)ino2).value.getClass()));
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}//end method compare
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}//end class ElemComparator
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