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Eclipse Platform
Release 3.0

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Package org.eclipse.compare.rangedifferencer

Provides support for finding the differences between two or three sequences of comparable entities.

See:
Description

Interface Summary

IRangeComparator

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

Class Summary

RangeDifference	Description of a change between two or three ranges of comparable entities.
RangeDifferencer	A RangeDifferencer finds the differences between two or three IRangeComparators.

Package org.eclipse.compare.rangedifferencer Description

Provides support for finding the differences between two or three sequences of comparable entities.

Package Specification

The class RangeDifferencer finds longest sequences of matching and non-matching comparable entities. Its implementation is based on an objectified version of the algorithm described in: A File Comparison Program, by Webb Miller and Eugene W. Myers, Software Practice and Experience, Vol. 15, Nov. 1985.

Clients must supply the input to the differencer as an implementation of the IRangeComparator interface. An IRangeComparator breaks the input data into a sequence of entities and provides a method for comparing one entity with the entity in another IRangeComparator.

For example, to compare two text documents and find longest common sequences of matching and non-matching lines, the implementation of IRangeComparator must break the document into lines and provide a method for testing whether two lines are considered equal. See org.eclipse.compare.internal.DocLineComparator for how this can be done.

The differencer returns the differences among these sequences as an array of RangeDifference objects. Every single RangeDifference describes the kind of difference (no change, change, addition, deletion) and the corresponding ranges of the underlying comparable entities in the two or three inputs.