org.eclipse.compare.rangedifferencer
Interface IRangeComparator

All Known Subinterfaces:

ITokenComparator

public interface IRangeComparator

For breaking an object to compare into a sequence of comparable entities.

It is used by RangeDifferencer to find longest sequences of matching and non-matching ranges.

For example, to compare two text documents and find longest common sequences of matching and non-matching lines, the implementation must break the document into lines. getRangeCount would return the number of lines in the document, and rangesEqual would compare a specified line given with one in another IRangeComparator.

Clients should implement this interface; there is no standard implementation.

Method Summary

int	getRangeCount() Returns the number of comparable entities.
boolean	rangesEqual(int thisIndex, IRangeComparator other, int otherIndex) Returns whether the comparable entity given by the first index matches an entity specified by the other IRangeComparator and index.
boolean	skipRangeComparison(int length, int maxLength, IRangeComparator other) Returns whether a comparison should be skipped because it would be too costly (or lengthy).

Method Detail

getRangeCount

public int getRangeCount()

Returns the number of comparable entities.

Returns:

the number of comparable entities

rangesEqual

public boolean rangesEqual(int thisIndex,
                           IRangeComparator other,
                           int otherIndex)

Returns whether the comparable entity given by the first index matches an entity specified by the other IRangeComparator and index.

Parameters:

thisIndex - the index of the comparable entity within this IRangeComparator

other - the IRangeComparator to compare this with

otherIndex - the index of the comparable entity within the other IRangeComparator

Returns:

true if the comparable entities are equal

skipRangeComparison

public boolean skipRangeComparison(int length,
                                   int maxLength,
                                   IRangeComparator other)

Returns whether a comparison should be skipped because it would be too costly (or lengthy).

Parameters:

length - a number on which to base the decision whether to return true or false

maxLength - another number on which to base the decision whether to return true or false

other - the other IRangeComparator to compare with

Returns:

true to avoid a too lengthy range comparison