Warn on using global namespace.

Test preventing empty namespaces.

Author: jarrodcodes

src/main/java/com/bettercloud/vault/Vault.java

@@ -65,6 +65,9 @@ public class Vault {
      */
     public Vault(final VaultConfig vaultConfig) {
         this.vaultConfig = vaultConfig;
+        if (this.vaultConfig.getNameSpace() != null && !this.vaultConfig.getNameSpace().isEmpty()) {
+            System.out.println(String.format("The NameSpace %s has been bound to this Vault instance. Please keep this in mind when running operations.", this.vaultConfig.getNameSpace()));
+        }
         if (this.vaultConfig.getSecretsEnginePathMap().isEmpty() && this.vaultConfig.getGlobalEngineVersion() == null) {
             System.out.println("Constructing a Vault instance with no provided Engine version, defaulting to version 2.");
             this.vaultConfig.setEngineVersion(2);
@@ -81,6 +84,9 @@ public Vault(final VaultConfig vaultConfig, final Integer engineVersion) {
         }
         vaultConfig.setEngineVersion(engineVersion);
         this.vaultConfig = vaultConfig;
+        if (this.vaultConfig.getNameSpace() != null && !this.vaultConfig.getNameSpace().isEmpty()) {
+            System.out.println(String.format("The Namespace %s has been bound to this Vault instance. Please keep this in mind when running operations.", this.vaultConfig.getNameSpace()));
+        }
     }
 
     /**
@@ -97,6 +103,9 @@ public Vault(final VaultConfig vaultConfig, final Integer engineVersion) {
     public Vault(final VaultConfig vaultConfig, final Boolean useSecretsEnginePathMap, final Integer globalFallbackVersion)
             throws VaultException {
         this.vaultConfig = vaultConfig;
+        if (this.vaultConfig.getNameSpace() != null && !this.vaultConfig.getNameSpace().isEmpty()) {
+            System.out.println(String.format("The Namespace %s has been bound to this Vault instance. Please keep this in mind when running operations.", this.vaultConfig.getNameSpace()));
+        }
         this.vaultConfig.setEngineVersion(globalFallbackVersion);
         if (useSecretsEnginePathMap && this.vaultConfig.getSecretsEnginePathMap().isEmpty()) {
             try {

src/main/java/com/bettercloud/vault/VaultConfig.java

@@ -85,6 +85,7 @@ public VaultConfig environmentLoader(final EnvironmentLoader environmentLoader)
      * finalization with the build() method
      */
     public VaultConfig nameSpace(final String nameSpace) {
+        assert !nameSpace.isEmpty();
         this.nameSpace = nameSpace;
         return this;
     }

src/test/java/com/bettercloud/vault/VaultTests.java

@@ -30,11 +30,21 @@ public void testGlobalEngineVersionVaultConstructor() {
 
     @Test
     public void testNameSpaceProvidedVaultConstructor() {
-        VaultConfig vaultConfig = new VaultConfig().nameSpace("namespace");
+        VaultConfig vaultConfig = new VaultConfig().nameSpace("testNameSpace");
         Vault vault = new Vault(vaultConfig, 1);
         Assert.assertNotNull(vault);
     }
 
+    @Test
+    public void testNameSpaceProvidedVaultConstructorCannotBeEmpty() {
+        try {
+            VaultConfig vaultConfig = new VaultConfig().nameSpace("");
+        } catch (AssertionError e) {
+            Assert.assertEquals(e.getClass(), AssertionError.class);
+        }
+    }
+
+
     @Test
     public void testNameSpaceNotProvidedVaultConstructor() {
         VaultConfig vaultConfig = new VaultConfig().nameSpace(null);