Revert "Merge pull request #22068 from vespa-engine/jonmv/unify-hostname-classes"

This reverts commit 8aa4c83df5ce7843c040afa41706fcc7c3afd030, reversing
changes made to f95ad44fae879da9db19f73eabe62c53baeb0c36.

5 files changed, 60 insertions, 14 deletions

diff --git a/vespajlib/abi-spec.json b/vespajlib/abi-spec.json
index 6044666ebf8..ae69564b671 100644
--- a/vespajlib/abi-spec.json
+++ b/vespajlib/abi-spec.json
@@ -350,13 +350,13 @@
     "fields": []
   },
   "com.yahoo.net.HostName": {
-    "superClass": "java.lang.Object",
+    "superClass": "ai.vespa.validation.PatternedStringWrapper",
     "interfaces": [],
     "attributes": [
       "public"
     ],
     "methods": [
-      "public void <init>()",
+      "public static com.yahoo.net.HostName of(java.lang.String)",
       "public static synchronized java.lang.String getLocalhost()",
       "public static void setHostNameForTestingOnly(java.lang.String)"
     ],
diff --git a/vespajlib/src/main/java/ai/vespa/http/DomainName.java b/vespajlib/src/main/java/ai/vespa/http/DomainName.java
index 737f6b6d863..a566f5b95be 100644
--- a/vespajlib/src/main/java/ai/vespa/http/DomainName.java
+++ b/vespajlib/src/main/java/ai/vespa/http/DomainName.java
@@ -15,12 +15,12 @@ import static ai.vespa.validation.Validation.requireMatch;
  */
 public class DomainName extends PatternedStringWrapper<DomainName> {
 
-    protected static final Pattern labelPattern = Pattern.compile("([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9-]{0,61}[A-Za-z0-9])");
-    protected static final Pattern domainNamePattern = Pattern.compile("(" + labelPattern + "\\.)*" + labelPattern);
+    static final Pattern labelPattern = Pattern.compile("([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9-]{0,61}[A-Za-z0-9])");
+    static final Pattern domainNamePattern = Pattern.compile("(" + labelPattern + "\\.)*" + labelPattern);
 
     public static final DomainName localhost = DomainName.of("localhost");
 
-    protected DomainName(String value) {
+    private DomainName(String value) {
         super(requireLength(value, "domain name length", 1, 255), domainNamePattern, "domain name");
     }
 
diff --git a/vespajlib/src/main/java/ai/vespa/validation/StringWrapper.java b/vespajlib/src/main/java/ai/vespa/validation/StringWrapper.java
index 12be0002f6f..0937627b57e 100644
--- a/vespajlib/src/main/java/ai/vespa/validation/StringWrapper.java
+++ b/vespajlib/src/main/java/ai/vespa/validation/StringWrapper.java
@@ -40,7 +40,7 @@ public abstract class StringWrapper<T extends StringWrapper<T>> implements Compa
     @Override
     public final boolean equals(Object o) {
         if (this == o) return true;
-        if ( ! (o instanceof StringWrapper<?>)) return false;
+        if (o == null || getClass() != o.getClass()) return false;
         return value.equals(((StringWrapper<?>) o).value);
     }
 
diff --git a/vespajlib/src/main/java/com/yahoo/net/HostName.java b/vespajlib/src/main/java/com/yahoo/net/HostName.java
index 7446771f57c..20f1008055e 100644
--- a/vespajlib/src/main/java/com/yahoo/net/HostName.java
+++ b/vespajlib/src/main/java/com/yahoo/net/HostName.java
@@ -1,18 +1,39 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.net;
 
+import ai.vespa.http.DomainName;
+import ai.vespa.validation.PatternedStringWrapper;
+
 import java.util.Optional;
+import java.util.regex.Pattern;
+
+import static ai.vespa.validation.Validation.requireLength;
 
 /**
- * This class has utilities for getting the hostname of the system running the JVM.
+ * Hostnames match {@link #hostNamePattern}, and are restricted to 64 characters in length.
+ *
+ * This class also has utilities for getting the hostname of the system running the JVM.
  * Detection of the hostname is now done before starting any Vespa
  * programs and provided in the environment variable VESPA_HOSTNAME;
  * if that variable isn't set a default of "localhost" is always returned.
  *
  * @author arnej
+ * @author jonmv
  */
-public class HostName {
+public class HostName extends PatternedStringWrapper<HostName> {
+
+    static final Pattern labelPattern = Pattern.compile("([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9-]{0,61}[A-Za-z0-9])");
+    static final Pattern hostNamePattern = Pattern.compile("(" + labelPattern + "\\.)*" + labelPattern);
 
-    private static String preferredHostName = null;
+    private static HostName preferredHostName = null;
+
+    private HostName(String value) {
+        super(requireLength(value, "hostname length", 1, 64), hostNamePattern, "hostname");
+    }
+
+    public static HostName of(String value) {
+        return new HostName(value);
+    }
 
     /**
      * Return a public and fully qualified hostname for localhost that
@@ -24,19 +45,19 @@ public class HostName {
         if (preferredHostName == null) {
             preferredHostName = getPreferredHostName();
         }
-        return preferredHostName;
+        return preferredHostName.value();
     }
 
-    static private String getPreferredHostName() {
+    static private HostName getPreferredHostName() {
         Optional<String> vespaHostEnv = Optional.ofNullable(System.getenv("VESPA_HOSTNAME"));
         if (vespaHostEnv.isPresent() && ! vespaHostEnv.get().trim().isEmpty()) {
-            return vespaHostEnv.get().trim();
+            return of(vespaHostEnv.get().trim());
         }
-        return "localhost";
+        return of("localhost");
     }
 
     public static void setHostNameForTestingOnly(String hostName) {
-        preferredHostName = hostName;
+        preferredHostName = HostName.of(hostName);
     }
 
 }
diff --git a/vespajlib/src/test/java/com/yahoo/net/HostNameTest.java b/vespajlib/src/test/java/com/yahoo/net/HostNameTest.java
index 2548c3cea60..fa756b31616 100644
--- a/vespajlib/src/test/java/com/yahoo/net/HostNameTest.java
+++ b/vespajlib/src/test/java/com/yahoo/net/HostNameTest.java
@@ -1,14 +1,39 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.net;
 
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
+/**
+ * @author jonmv
+ */
 public class HostNameTest {
 
     @Test
+    void testNames() {
+        HostName.of("name-123.0.321-eman");
+        HostName.of(("." + "a".repeat(32)).repeat(2).substring(1, 65));
+        HostName.of("123");
+
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("_"));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("-"));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("."));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("-foo"));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("foo-"));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of(".foo"));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("foo."));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("foo..bar"));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("foo.-.bar"));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("foo/"));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("foo%"));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of(("." + "a".repeat(32)).repeat(2).substring(1, 66)));
+        assertThrows(IllegalArgumentException.class, () -> HostName.of("a".repeat(64)));
+    }
+
+    @Test
     void testHostnameIsFound() {
         assertFalse(HostName.getLocalhost().isEmpty());
     }