Package org.jline.utils

Class DiffHelper

java.lang.Object

org.jline.utils.DiffHelper

public class DiffHelper
extends Object

Utility class for computing differences between strings with ANSI attribute awareness.

The DiffHelper class provides methods for computing the differences between two strings while being aware of ANSI escape sequences and text attributes. This allows for proper diffing of styled text without breaking the ANSI escape sequences.

Unlike standard diff algorithms, this implementation ensures that any text in a Diff object is a valid ANSI string with properly balanced escape sequences. This is particularly important when diffing AttributedStrings or other text with embedded styling information.

The diff algorithm identifies three types of operations:

• DELETE - Text that exists in the first string but not in the second
• INSERT - Text that exists in the second string but not in the first
• EQUAL - Text that is common to both strings

This class is particularly useful for implementing features like change highlighting in terminal applications, where differences between versions of text need to be displayed with proper styling.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	DiffHelper.Diff	Class representing one diff operation.
static enum	DiffHelper.Operation	The data structure representing a diff is a Linked list of Diff objects: {Diff(Operation.DELETE, "Hello"), Diff(Operation.INSERT, "Goodbye"), Diff(Operation.EQUAL, " world.")}

Method Summary

Modifier and Type	Method	Description
static List<DiffHelper.Diff>	diff(AttributedString text1, AttributedString text2)	Compute the differences between two attributed strings.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

diff

public static List<DiffHelper.Diff> diff(AttributedString text1,
 AttributedString text2)

Compute the differences between two attributed strings.

Returns a list of DiffHelper.Diff operations (EQUAL, INSERT, DELETE) that transform text1 into text2. Hidden character ranges are kept intact — they are never split across diff segments.

Parameters:

text1 - the original text

text2 - the modified text

Returns:

a list of diff operations