DefaultDiffEngine

The DefaultDiffEngine class allows to apply a GNU diff to get a list of differences for the left text and the right text. This class is not a Swing component, and allows to use the diff for non GUI usages (for example creating an Excel file with the content of the diff).

Usage

1. The DefaultDiffEngine(List, List) creates the engine with the left and right text content
2. The DiffEngine.populate() populates the diff

After calling the populate() method, you can use the DefaultDiffEngine.getLeftDiffLines() and DefaultDiffEngine.getRightDiffLines() to get the differences for the left and right content.

Each DiffEngine.DiffLine element in the left or right diff has the following methods:

• The DiffEngine.DiffLine.getLine() returns the text of the line
• The DiffEngine.DiffLine.getLineNumber() returns the line number
• The DiffEngine.DiffLine.getState() returns the state of the line in the diff. The state can be either:
• DiffEngine.UNCNANGED for an unchanged line between the left and the right
• DiffEngine.UPDATED for an updated line between the left and the right
• DiffEngine.DELETED for an deleted line between the left and the right
• DiffEngine.NEW for an new line between the left and the right

By default the left text value for a DiffEngine.NEW line, or the right text value for a DiffEngine.DELETED is null.

Example

      List<String> leftList = new ArrayList<>();
      leftList.add("firstline");
      leftList.add("secondline");

      List<String> rightList = new ArrayList<>();
      rightList.add("firstline");
      
      DefaultDiffEngine diffEngine = new DefaultDiffEngine(leftList, rightList);
      DiffBase diffBase = diffEngine.populate();
      assertTrue("Content is changed", diffBase.isChanged());
      
      List<DiffEngine.DiffLine> leftDiff = diffEngine.getLeftDiffLines();
      List<DiffEngine.DiffLine> rightDiff = diffEngine.getRightDiffLines();