Package com.logicaldoc.comparison.basic

Class DiffMatch

java.lang.Object
com.logicaldoc.comparison.basic.DiffMatch
public class DiffMatch extends Object
Class containing the diff, match and patch methods. Also contains the behaviour settings.

  • Constructor Details

    • DiffMatch

      public DiffMatch()

  • Method Details

    • diffMain

      public List<DiffMatch.Diff> diffMain(String text1, String text2)
      Find the differences between two texts. Run a faster, slightly less optimal diff. This method allows the 'checklines' of diff_main() to be optional. Most of the time checklines is wanted, so default to true.
      Parameters:
      text1 - Old string to be diffed.
      text2 - New string to be diffed.
      Returns:
      Linked List of Diff objects.

    • diffMain

      public List<DiffMatch.Diff> diffMain(String text1, String text2, boolean checklines)
      Find the differences between two texts.
      Parameters:
      text1 - Old string to be diffed.
      text2 - New string to be diffed.
      checklines - Speedup flag. If false, then don't run a line-level diff first to identify the changed areas. If true, then run a faster slightly less optimal diff.
      Returns:
      Linked List of Diff objects.

    • diffCommonPrefix

      public int diffCommonPrefix(String text1, String text2)
      Determine the common prefix of two strings
      Parameters:
      text1 - First string.
      text2 - Second string.
      Returns:
      The number of characters common to the start of each string.

    • diffCommonSuffix

      public int diffCommonSuffix(String text1, String text2)
      Determine the common suffix of two strings
      Parameters:
      text1 - First string.
      text2 - Second string.
      Returns:
      The number of characters common to the end of each string.

    • diffCleanupSemantic

      public void diffCleanupSemantic(LinkedList<DiffMatch.Diff> diffs)
      Reduce the number of edits by eliminating semantically trivial equalities.
      Parameters:
      diffs - LinkedList of Diff objects.

    • diffCleanupSemanticLossless

      public void diffCleanupSemanticLossless(LinkedList<DiffMatch.Diff> diffs)
      Look for single edits surrounded on both sides by equalities which can be shifted sideways to align the edit to a word boundary. e.g: The c<ins>at c</ins>ame. -> The <ins>cat </ins>came.
      Parameters:
      diffs - LinkedList of Diff objects.

    • diffCleanupEfficiency

      public void diffCleanupEfficiency(LinkedList<DiffMatch.Diff> diffs)
      Reduce the number of edits by eliminating operationally trivial equalities.
      Parameters:
      diffs - LinkedList of Diff objects.

    • diffCleanupMerge

      public void diffCleanupMerge(LinkedList<DiffMatch.Diff> diffs)
      Reorder and merge like edit sections. Merge equalities. Any edit section can move as long as it doesn't cross an equality.
      Parameters:
      diffs - LinkedList of Diff objects.

    • diffXIndex

      public int diffXIndex(LinkedList<DiffMatch.Diff> diffs, int loc)
      loc is a location in text1, compute and return the equivalent location in text2. e.g. "The cat" vs "The big cat", 1->1, 5->8
      Parameters:
      diffs - LinkedList of Diff objects.
      loc - Location within text1.
      Returns:
      Location within text2.

    • diffPrettyHtml

      public String diffPrettyHtml(List<DiffMatch.Diff> diffs)
      Convert a Diff list into a pretty HTML report.
      Parameters:
      diffs - LinkedList of Diff objects.
      Returns:
      HTML representation.

    • diffText1

      public String diffText1(LinkedList<DiffMatch.Diff> diffs)
      Compute and return the source text (all equalities and deletions).
      Parameters:
      diffs - LinkedList of Diff objects.
      Returns:
      Source text.

    • diffText2

      public String diffText2(LinkedList<DiffMatch.Diff> diffs)
      Compute and return the destination text (all equalities and insertions).
      Parameters:
      diffs - LinkedList of Diff objects.
      Returns:
      Destination text.

    • diffLevenshtein

      public int diffLevenshtein(LinkedList<DiffMatch.Diff> diffs)
      Compute the Levenshtein distance; the number of inserted, deleted or substituted characters.
      Parameters:
      diffs - LinkedList of Diff objects.
      Returns:
      Number of changes.

    • diffToDelta

      public String diffToDelta(LinkedList<DiffMatch.Diff> diffs) throws UnsupportedEncodingException
      Crush the diff into an encoded string which describes the operations required to transform text1 into text2. E.g. =3\t-2\t+ing -> Keep 3 chars, delete 2 chars, insert 'ing'. Operations are tab-separated. Inserted text is escaped using %xx notation.
      Parameters:
      diffs - Array of Diff objects.
      Returns:
      Delta text.
      Throws:
      UnsupportedEncodingException - In case the system does not suppot UTF-8

    • diffFromDelta

      public LinkedList<DiffMatch.Diff> diffFromDelta(String text1, String delta) throws IllegalArgumentException, UnsupportedEncodingException
      Given the original text1, and an encoded string which describes the operations required to transform text1 into text2, compute the full diff.
      Parameters:
      text1 - Source string for the diff.
      delta - Delta text.
      Returns:
      Array of Diff objects or null if invalid.
      Throws:
      IllegalArgumentException - If invalid input.
      UnsupportedEncodingException - The system does not support UTF-8

    • matchMain

      public int matchMain(String text, String pattern, int loc)
      Locate the best instance of 'pattern' in 'text' near 'loc'. Returns -1 if no match found.
      Parameters:
      text - The text to search.
      pattern - The pattern to search for.
      loc - The location to search around.
      Returns:
      Best match index or -1.

    • patchMake

      public List<DiffMatch.Patch> patchMake(String text1, String text2)
      Compute a list of patches to turn text1 into text2. A set of diffs will be computed.
      Parameters:
      text1 - Old text.
      text2 - New text.
      Returns:
      LinkedList of Patch objects.

    • patchMake

      public LinkedList<DiffMatch.Patch> patchMake(LinkedList<DiffMatch.Diff> diffs)
      Compute a list of patches to turn text1 into text2. text1 will be derived from the provided diffs.
      Parameters:
      diffs - Array of Diff objects for text1 to text2.
      Returns:
      LinkedList of Patch objects.

    • patchMake

      public LinkedList<DiffMatch.Patch> patchMake(String text1, LinkedList<DiffMatch.Diff> diffs)
      Compute a list of patches to turn text1 into text2. text2 is not provided, diffs are the delta between text1 and text2.
      Parameters:
      text1 - Old text.
      diffs - Array of Diff objects for text1 to text2.
      Returns:
      LinkedList of Patch objects.

    • patchDeepCopy

      public LinkedList<DiffMatch.Patch> patchDeepCopy(LinkedList<DiffMatch.Patch> patches)
      Given an array of patches, return another array that is identical.
      Parameters:
      patches - Array of Patch objects.
      Returns:
      Array of Patch objects.

    • patchApply

      public Object[] patchApply(LinkedList<DiffMatch.Patch> patches, String text)
      Merge a set of patches onto the text. Return a patched text, as well as an array of true/false values indicating which patches were applied.
      Parameters:
      patches - Array of Patch objects
      text - Old text.
      Returns:
      Two element Object array, containing the new text and an array of boolean values.

    • patchAddPadding

      public String patchAddPadding(LinkedList<DiffMatch.Patch> patches)
      Add some padding on text start and end so that edges can match something. Intended to be called only from within patch_apply.
      Parameters:
      patches - Array of Patch objects.
      Returns:
      The padding string added to each side.

    • patchSplitMax

      public void patchSplitMax(LinkedList<DiffMatch.Patch> patches)
      Look through the patches and break up any which are longer than the maximum limit of the match algorithm. Intended to be called only from within patch_apply.
      Parameters:
      patches - LinkedList of Patch objects.

    • patchToText

      public String patchToText(List<DiffMatch.Patch> patches)
      Take a list of patches and return a textual representation.
      Parameters:
      patches - List of Patch objects.
      Returns:
      Text representation of patches.

    • patchFromText

      public List<DiffMatch.Patch> patchFromText(String textline) throws IllegalArgumentException, UnsupportedEncodingException
      Parse a textual representation of patches and return a List of Patch objects.
      Parameters:
      textline - Text representation of patches.
      Returns:
      List of Patch objects.
      Throws:
      IllegalArgumentException - If invalid input.
      UnsupportedEncodingException - The system does not support UTF-8