com.github.robtimus.obfuscation

Class Obfuscator.SplitPoint

java.lang.Object

com.github.robtimus.obfuscation.Obfuscator.SplitPoint

Enclosing class:

Obfuscator

public abstract static class Obfuscator.SplitPoint
extends Object

A point in a CharSequence or Reader to split obfuscation. Like Obfuscator.untilLength(int), this can be used to combine obfuscators. For instance, to obfuscate email addresses:

 Obfuscator localPartObfuscator = portion()
         .keepAtStart(1)
         .keepAtEnd(1)
         .withFixedTotalLength(8)
         .build();
 Obfuscator domainObfuscator = none();
 Obfuscator obfuscator = SplitPoint.atFirst('@').splitTo(localPartObfuscator, domainObfuscator);
 // Everything before @ will be obfuscated using localPartObfuscator, everything after @ will not be obfuscated
 // Example input: test@example.org
 // Example output: t******t@example.org
 

Unlike Obfuscator.untilLength(int) it's not possible to chain splitting, but it's of course possible to nest it:

 Obfuscator localPartObfuscator = portion()
         .keepAtStart(1)
         .keepAtEnd(1)
         .withFixedTotalLength(8)
         .build();
 Obfuscator domainObfuscator = SplitPoint.atLast('.').splitTo(all(), none());
 Obfuscator obfuscator = SplitPoint.atFirst('@').splitTo(localPartObfuscator, domainObfuscator);
 // Everything before @ will be obfuscated using localPartObfuscator, everything after @ will be obfuscated until the last dot
 // Example input: test@example.org
 // Example output: t******t@*******.org
 

Sub classing

To create a sub class, implement both splitStart(CharSequence, int, int) and splitLength(). Obfuscators created by calling splitTo(Obfuscator, Obfuscator) use these two methods to determine how to split the text to obfuscate. If splitStart(CharSequence, int, int) returns -1, only the first obfuscator will be used. Otherwise, where splitStart is the result of calling splitStart(CharSequence, int, int):

• The range from start to splitStart will be obfuscated using the first obfuscator.
• The range from splitStart to splitStart + splitLength() will not be obfuscated.
• The range from splitStart + splitLength() to end will be obfuscated using the second obfuscator.

Equality

Equality of split points is used in equality of obfuscators created using splitTo(Obfuscator, Obfuscator). It's therefore advised to implement Object.equals(Object) (and Object.hashCode()) so logically equivalent split points will be considered equal.

String representation

The string representation of split points is used in the string representation of obfuscators created using splitTo(Obfuscator, Obfuscator). It's therefore advised to override Object.toString() to something meaningful.

Author:

Rob Spoor

Since:

1.5

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SplitPoint() Creates a new split point.

Method Summary

Modifier and Type	Method and Description
static Obfuscator.SplitPoint	atFirst(char c) Creates a new split point that splits at the first occurrence of a character.
static Obfuscator.SplitPoint	atLast(char c) Creates a new split point that splits at the last occurrence of a character.
static Obfuscator.SplitPoint	atNth(char c, int occurrence) Creates a new split point that splits at a specific occurrence of a character.
protected abstract int	splitLength() Returns the length of CharSequence ranges to not obfuscate when splitting.
protected abstract int	splitStart(CharSequence s, int start, int end) For a given CharSequence range, finds the index where to start to split.
Obfuscator	splitTo(Obfuscator beforeSplitPoint, Obfuscator afterSplitPoint) Creates an obfuscator that splits obfuscation at this split point.

Methods inherited from class java.lang.Object

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

Constructor Detail

SplitPoint

protected SplitPoint()

Creates a new split point.

Method Detail

atFirst

public static Obfuscator.SplitPoint atFirst(char c)

Creates a new split point that splits at the first occurrence of a character. This split point is exclusive; the character itself will not be obfuscated.

Parameters:

c - The character to split at.

Returns:

The created split point.

atLast

public static Obfuscator.SplitPoint atLast(char c)

Creates a new split point that splits at the last occurrence of a character. This split point is exclusive; the character itself will not be obfuscated.

Parameters:

c - The character to split at.

Returns:

The created split point.

atNth

public static Obfuscator.SplitPoint atNth(char c,
                                          int occurrence)

Creates a new split point that splits at a specific occurrence of a character. This split point is exclusive; the character itself will not be obfuscated.

Parameters:

c - The character to split at.

occurrence - The zero-based occurrence of the character to split at.

Returns:

The created split point.

Throws:

IllegalArgumentException - If the given occurrence is negative.

splitStart

protected abstract int splitStart(CharSequence s,
                                  int start,
                                  int end)

For a given CharSequence range, finds the index where to start to split.

Parameters:

s - The CharSequence to find the split start index for.

start - The start index in the CharSequence of the range to find the split start index in, inclusive.

end - The end index in the CharSequence of the range to find the split start index in, exclusive.

Returns:

The index in the given CharSequence, between the given start and end indexes, where to start to split, or -1 to not split.

splitLength

protected abstract int splitLength()

Returns the length of CharSequence ranges to not obfuscate when splitting. All characters with an index between splitStart and splitStart + splitLength(), where splitStart is the result of calling splitStart(CharSequence, int, int), will not be obfuscated.

Returns:

The length of CharSequence ranges to not obfuscate when splitting.

splitTo

public final Obfuscator splitTo(Obfuscator beforeSplitPoint,
                                Obfuscator afterSplitPoint)

Creates an obfuscator that splits obfuscation at this split point. The part of the CharSequence or Reader before the split point will be obfuscated by one obfuscator, the part after the split point by another.

Parameters:

beforeSplitPoint - The obfuscator to use before the split point.

afterSplitPoint - The obfuscator to use after the split point.

Returns:

The created obfuscator.