Add files that INtelliJ removed

1 files changed, 42 insertions, 0 deletions

diff --git a/vespajlib/src/main/java/com/yahoo/net/HostName.java b/vespajlib/src/main/java/com/yahoo/net/HostName.java
new file mode 100644
index 00000000000..7446771f57c
--- /dev/null
+++ b/vespajlib/src/main/java/com/yahoo/net/HostName.java
@@ -0,0 +1,42 @@
+package com.yahoo.net;
+
+import java.util.Optional;
+
+/**
+ * This class 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
+ */
+public class HostName {
+
+    private static String preferredHostName = null;
+
+    /**
+     * Return a public and fully qualified hostname for localhost that
+     * resolves to an IP address on a network interface.
+     *
+     * @return the preferred name of localhost
+     */
+    public static synchronized String getLocalhost() {
+        if (preferredHostName == null) {
+            preferredHostName = getPreferredHostName();
+        }
+        return preferredHostName;
+    }
+
+    static private String getPreferredHostName() {
+        Optional<String> vespaHostEnv = Optional.ofNullable(System.getenv("VESPA_HOSTNAME"));
+        if (vespaHostEnv.isPresent() && ! vespaHostEnv.get().trim().isEmpty()) {
+            return vespaHostEnv.get().trim();
+        }
+        return "localhost";
+    }
+
+    public static void setHostNameForTestingOnly(String hostName) {
+        preferredHostName = hostName;
+    }
+
+}