Remove (curse word) separator incompatibility

The curse word protection of the original algorithm implementation does
not allow to modify the separators. This API provided methods to
customize those causing invalid and inconsistent hash- and numbers
values.

GH-9

Author: arcticicestudio

src/main/java/com/arcticicestudio/icecore/hashids/Hashids.java

@@ -16,8 +16,7 @@
  *    Generated strings can have a {@code minHashLength}.
  * </p>
  * <p>
- *   If used to obfuscates identities, make sure to not expose your {@code salt}, {@code alphabet} nor
- * {@code separators} to a client, client-side is not safe.
+ *   If used to obfuscate identities make sure to not expose your {@code salt} or {@code alphabet}.
  * </p>
  * <p>
  *   Only positive numbers are supported.
@@ -51,12 +50,12 @@ public final class Hashids {
   public static final String DEFAULT_ALPHABET = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
 
   /**
-   * Holds the default separators.
+   * The default separators.
    * <p>
    *   Used to prevent the generation of strings that contain bad, offensive and rude words.
    * </p>
    */
-  public static final String DEFAULT_SEPARATORS = "cfhistuCFHISTU";
+  private static final String DEFAULT_SEPARATORS = "cfhistuCFHISTU";
 
   /**
    * Holds the maximum number value.
@@ -90,7 +89,6 @@ public final class Hashids {
   private final String guards;
   private final int minHashLength;
   private final String salt;
-  private final String separators;
 
   /**
    * Constructs a new instance with all default values.
@@ -99,20 +97,18 @@ public final class Hashids {
    *     <li>no salt</li>
    *     <li>no minimal hash length</li>
    *     <li>{@link #DEFAULT_ALPHABET}</li>
-   *     <li>{@link #DEFAULT_SEPARATORS}</li>
    *   </ul>
    */
   public Hashids() {
     this("", 0);
   }
 
   /**
-   * Constructs a new instance with the specified salt and the default minimal hash length, alphabet and separators.
+   * Constructs a new instance with the specified salt, the minimal hash length and default alphabet.
    * <p>
    *   <ul>
    *     <li>no minimal hash length</li>
    *     <li>{@link #DEFAULT_ALPHABET}</li>
-   *     <li>{@link #DEFAULT_SEPARATORS}</li>
    *   </ul>
    *
    * @param salt the salt value
@@ -122,12 +118,10 @@ public Hashids(String salt) {
   }
 
   /**
-   * Constructs a new instance with the specified salt and the minimal hash length and the default alphabet and
-   * separators.
+   * Constructs a new instance with the specified salt and hash length and the default alphabet.
    * <p>
    *   <ul>
    *     <li>{@link #DEFAULT_ALPHABET}</li>
-   *     <li>{@link #DEFAULT_SEPARATORS}</li>
    *   </ul>
    *
    * @param salt the salt value
@@ -138,11 +132,10 @@ public Hashids(String salt, int minHashLength) {
   }
 
   /**
-   * Constructs a new instance with the specified salt and alphabet and the default minimal hash length and separators.
+   * Constructs a new instance with the specified salt and alphabet and the minimal hash length.
    * <p>
    *   <ul>
    *     <li>no minimal hash length</li>
-   *     <li>{@link #DEFAULT_SEPARATORS}</li>
    *   </ul>
    *
    * @param salt the salt value
@@ -153,29 +146,13 @@ public Hashids(String salt, String alphabet) {
   }
 
   /**
-   * Constructs a new instance with the specified salt, minimal hash length and alphabet and the default separators.
-   * <p>
-   *   <ul>
-   *     <li>{@link #DEFAULT_SEPARATORS}</li>
-   *   </ul>
+   * Constructs a new instance with the specified salt, minimal hash length and alphabet.
    *
    * @param salt the salt value
    * @param minHashLength the minimal length of the hash
    * @param alphabet the alphabet value
    */
   public Hashids(String salt, int minHashLength, String alphabet) {
-    this(salt, minHashLength, alphabet, DEFAULT_SEPARATORS);
-  }
-
-  /**
-   * Constructs a new instance with the specified salt, minimal hash length, alphabet and separators.
-   *
-   * @param salt the salt value
-   * @param minHashLength the minimal length of the hash
-   * @param alphabet the alphabet value
-   * @param separators the chained separators
-   */
-  public Hashids(String salt, int minHashLength, String alphabet, String separators) {
     if (alphabet == null) {
       throw new IllegalArgumentException("alphabet was null");
     }
@@ -203,11 +180,8 @@ public Hashids(String salt, int minHashLength, String alphabet, String separator
       throw new IllegalArgumentException("Alphabet cannot contains spaces");
     }
 
-    /*
-     * Separators should contain only characters present in alphabet.
-     * Alphabet should not contain separators.
-     */
-    StringBuilder seps = new StringBuilder(separators == null ? "" : separators);
+    // Alphabet should not contain separators.
+    StringBuilder seps = new StringBuilder(DEFAULT_SEPARATORS);
     for (int sepIdx = 0; sepIdx < seps.length(); sepIdx++) {
       int alphaIdx = uniqueAlphabet.indexOf(String.valueOf(seps.charAt(sepIdx)));
       if (alphaIdx == -1) {
@@ -247,7 +221,6 @@ public Hashids(String salt, int minHashLength, String alphabet, String separator
     }
 
     this.alphabet = uniqueAlphabet.toString();
-    this.separators = seps.toString();
   }
 
   /**
@@ -261,14 +234,12 @@ public Hashids(String salt, int minHashLength, String alphabet, String separator
    *     <li>no salt</li>
    *     <li>no minimum hash length</li>
    *     <li>{@link #DEFAULT_ALPHABET}</li>
-   *     <li>{@link #DEFAULT_SEPARATORS}</li>
    *   </ul>
    */
   public static final class Builder {
 
     private final String salt;
     private final String alphabet;
-    private final String separators;
     private final int minHashLength;
 
     /**
@@ -277,15 +248,13 @@ public static final class Builder {
     public Builder() {
       this.salt = "";
       this.alphabet = DEFAULT_ALPHABET;
-      this.separators = DEFAULT_SEPARATORS;
       this.minHashLength = 0;
     }
 
-    private Builder(String salt, String alphabet, String separators, int minHashLength) {
+    private Builder(String salt, int minHashLength, String alphabet) {
       this.salt = salt;
-      this.alphabet = alphabet;
-      this.separators = separators;
       this.minHashLength = minHashLength;
+      this.alphabet = alphabet;
     }
 
     /**
@@ -295,7 +264,7 @@ private Builder(String salt, String alphabet, String separators, int minHashLeng
      * @return The builder instance with the specified salt
      */
     public Builder salt(String salt) {
-      return new Builder(salt, alphabet, separators, minHashLength);
+      return new Builder(salt, minHashLength, alphabet);
     }
 
     /**
@@ -305,17 +274,7 @@ public Builder salt(String salt) {
      * @return The builder instance with the specified custom alphabet
      */
     public Builder alphabet(String alphabet) {
-      return new Builder(salt, alphabet, separators, minHashLength);
-    }
-
-    /**
-     * Sets the custom separators string.
-     *
-     * @param separators The string to use as custom alphabet
-     * @return The builder instance with the specified custom separators
-     */
-    public Builder separators(String separators) {
-      return new Builder(salt, alphabet, separators, minHashLength);
+      return new Builder(salt, minHashLength, alphabet);
     }
 
     /**
@@ -325,7 +284,7 @@ public Builder separators(String separators) {
      * @return The builder instance with the minimum hash length
      */
     public Builder minHashLength(int minHashLength) {
-      return new Builder(salt, alphabet, separators, minHashLength);
+      return new Builder(salt, minHashLength, alphabet);
     }
 
     /**
@@ -334,7 +293,7 @@ public Builder minHashLength(int minHashLength) {
      * @return The {@link Hashids} instance
      */
     public Hashids build() {
-      return new Hashids(salt, minHashLength, alphabet, separators);
+      return new Hashids(salt, minHashLength, alphabet);
     }
   }
 
@@ -421,8 +380,8 @@ private String doEncode(long... numbers) {
 
       if (idx + 1 < numbers.length) {
         num %= ((int) last.charAt(0) + idx);
-        sepsIdx = (int) (num % separators.length());
-        result.append(separators.charAt(sepsIdx));
+        sepsIdx = (int) (num % DEFAULT_SEPARATORS.length());
+        result.append(DEFAULT_SEPARATORS.charAt(sepsIdx));
       }
     }
 
@@ -463,7 +422,7 @@ private long[] doDecode(String hash, String alphabet) {
     if (!hashBreakdown.isEmpty()) {
       final char lottery = hashBreakdown.charAt(0);
       hashBreakdown = hashBreakdown.substring(1);
-      hashBreakdown = hashBreakdown.replaceAll("[" + separators + "]", " ");
+      hashBreakdown = Pattern.compile("[" + DEFAULT_SEPARATORS + "]").matcher(hashBreakdown).replaceAll(" ");
       hashArray = hashBreakdown.split(" ");
 
       String buffer;

src/test/java/com/arcticicestudio/icecore/hashids/HashidsTest.java

@@ -64,28 +64,6 @@ public void oneNumberWithCustomMinimumHashLength() {
     assertEquals(decoded[0], number);
   }
 
-  @Test
-  public void oneNumberWithoutSeparators() {
-    Hashids hashids = new Hashids("salt", 0, Hashids.DEFAULT_ALPHABET, null);
-    long number = 12_345L;
-    String hash = hashids.encode(number);
-    long[] decoded = hashids.decode(hash);
-
-    assertEquals(1, decoded.length);
-    assertEquals(number, decoded[0]);
-  }
-
-  @Test
-  public void oneNumberWithCustomSeparators() {
-    Hashids hashids = new Hashids("salt", 0, Hashids.DEFAULT_ALPHABET, "abcdefgABCDEFG1234567");
-    long number = 12_345L;
-    String hash = hashids.encode(number);
-    long[] decoded = hashids.decode(hash);
-
-    assertEquals(1, decoded.length);
-    assertEquals(number, decoded[0]);
-  }
-
   @Test
   public void oneNumberWithLargeCustomMinimumHashLength() {
     Hashids hashids = new Hashids("salt", 1000);
@@ -229,7 +207,6 @@ public void hashidsBuilder() {
       .salt("salt")
       .minHashLength(16)
       .alphabet(Hashids.DEFAULT_ALPHABET)
-      .separators(Hashids.DEFAULT_SEPARATORS)
       .build();
     long number = 12_345L;
     long[] decoded = hashids.decode(hashids.encode(number));