Add normalize method (#51)

README.md

@@ -172,6 +172,16 @@ JMail.tryParse("test@example.com")
         () -> log.error("Could not send email to invalid email"));
 ```
 
+#### Get a normalized version of the email address
+
+```java
+// Get a normalized email address without any comments
+String normalized = JMail.tryParse("admin(comment)@mysite.org")
+    .map(Email::normalized);
+
+// normalized == "admin@mysite.org"
+```
+
 ### Additional Validation Rules
 
 #### Disallow IP Address Domain

src/main/java/com/sanctionco/jmail/Email.java

@@ -196,6 +196,22 @@ public TopLevelDomain topLevelDomain() {
     return tld;
   }
 
+  /**
+   * Return a "normalized" version of this email address. The normalized version
+   * is the same as the original email address, except that all comments and optional
+   * parts (identifiers, source routing) are removed. For example, the address
+   * {@code "test@(comment)example.com"} will return {@code "test@example.com"}.
+   *
+   * @return the normalized version of this email address
+   */
+  public String normalized() {
+    String domain = isIpAddress
+        ? "[" + this.domainWithoutComments + "]"
+        : this.domainWithoutComments;
+
+    return localPartWithoutComments + "@" + domain;
+  }
+
   /**
    * Get the string value of this email address. For example, the address
    * {@code "test@example.com"} will return {@code "test@example.com"}.

src/test/java/com/sanctionco/jmail/EmailTest.java

@@ -22,4 +22,23 @@ void staticConstructorParses() {
     assertThat(Email.of("invalid"))
         .isNotPresent();
   }
+
+  @Test
+  void ensureNormalizedIsCorrectForIpAddressEmail() {
+    String address = "aaa@[123.123.123.123]";
+
+    assertThat(Email.of(address))
+        .isPresent().get()
+        .returns(address, Email::normalized);
+  }
+
+  @Test
+  void ensureNormalizedIsCorrectForLongComment() {
+    String address = "first(Welcome to
 the (\"wonderful\" (!)) world
 of email)"
+        + "@test.org";
+
+    assertThat(Email.of(address))
+        .isPresent().get()
+        .returns("first@test.org", Email::normalized);
+  }
 }

src/test/java/com/sanctionco/jmail/JMailTest.java

@@ -89,7 +89,8 @@ void tryParseSetsCommentFields() {
         .returns("example.com", Email::domainWithoutComments)
         .returns(Arrays.asList("hello", "world"), Email::comments)
         .returns(Arrays.asList("example", "com"), Email::domainParts)
-        .returns(TopLevelDomain.DOT_COM, Email::topLevelDomain);
+        .returns(TopLevelDomain.DOT_COM, Email::topLevelDomain)
+        .returns("test@example.com", Email::normalized);
   }
 
   @Test
@@ -114,7 +115,8 @@ void addressWithSourceRoutingValidates() {
         .returns("final.domain", Email::domain)
         .returns(Arrays.asList("final", "domain"), Email::domainParts)
         .returns(TopLevelDomain.fromString("domain"), Email::topLevelDomain)
-        .returns(Arrays.asList("1st.relay", "2nd.relay"), Email::explicitSourceRoutes);
+        .returns(Arrays.asList("1st.relay", "2nd.relay"), Email::explicitSourceRoutes)
+        .returns("user@final.domain", Email::normalized);
   }
 
   @ParameterizedTest(name = "{0}")
@@ -145,19 +147,22 @@ void ensureIdentifiersAreParsed() {
     assertThat(JMail.tryParse(one)).isPresent().get()
         .hasToString(one)
         .returns(true, Email::hasIdentifier)
-        .returns("John Smith ", Email::identifier);
+        .returns("John Smith ", Email::identifier)
+        .returns("test@te.ex", Email::normalized);
 
     String two = "Admin<admin@te.ex>";
 
     assertThat(JMail.tryParse(two)).isPresent().get()
         .hasToString(two)
         .returns(true, Email::hasIdentifier)
-        .returns("Admin", Email::identifier);
+        .returns("Admin", Email::identifier)
+        .returns("admin@te.ex", Email::normalized);
 
     String none = "user@te.ex";
 
     assertThat(JMail.tryParse(none)).isPresent().get()
         .hasToString(none)
+        .returns(none, Email::normalized)
         .returns(false, Email::hasIdentifier)
         .extracting("identifier")
         .isNull();