Add useful isValidHashtag() for java

The implementation references isValidHashtag() in js and valid_hashtag() in ruby
twitter · Feb 16, 2019 · c5a2235 · c5a2235
1 parent 752b947
commit c5a2235
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diff --git a/java/src/main/java/com/twitter/twittertext/Validator.java b/java/src/main/java/com/twitter/twittertext/Validator.java
@@ -4,6 +4,8 @@
 
 package com.twitter.twittertext;
 
+import java.util.List;
+
 /**
  * A class for validating Tweet texts.
  */
@@ -36,6 +38,24 @@ public boolean isValidTweet(String text) {
  return TwitterTextParser.parseTweet(text).isValid;
  }
 
+ /**
+ * Checks if a given text is a valid hashtag.
+ *
+ * @param text text to validate
+ * @return whether the text is a valid hashtag or not
+ */
+ public boolean isValidHashtag(String text) {
+ if (text == null) {
+ return false;
+ }
+
+ Extractor extractor = new Extractor();
+ List<String> extracted = extractor.extractHashtags(text);
+
+ // Should extract the hashtag minus the # sign, hence the .substring(1)
+ return extracted.size() == 1 && extracted.get(0).equals(text.substring(1));
+ }
+
  public static boolean hasInvalidCharacters(String text) {
  return Regex.INVALID_CHARACTERS_PATTERN.matcher(text).matches();
  }

diff --git a/java/src/test/java/com/twitter/twittertext/ValidatorTest.java b/java/src/test/java/com/twitter/twittertext/ValidatorTest.java
@@ -50,4 +50,17 @@ public void testMutiByteCharacters() {
  assertTrue(validator.isValidTweet(builder.append(c).toString()));
  assertFalse(validator.isValidTweet(builder.append(c).toString()));
  }
+
+ public void testValidHashtags() {
+ assertTrue(validator.isValidHashtag("#test"));
+ assertTrue(validator.isValidHashtag("#\u53F0\u7063"));
+ }
+
+ public void testInvalidHashtags() {
+ assertFalse(validator.isValidHashtag("#test #test"));
+ assertFalse(validator.isValidHashtag("#test test"));
+ assertFalse(validator.isValidHashtag("#test,test"));
+ assertFalse(validator.isValidHashtag("test"));
+ assertFalse(validator.isValidHashtag(null));
+ }
 }