Seamless handling of Cross-level consumption of destination-fragment pairs

Author: panayotmarinov

cloudplatform/connectivity-destination-service/src/main/java/com/sap/cloud/sdk/cloudplatform/connectivity/TransparentProxyDestination.java

@@ -37,6 +37,8 @@ public class TransparentProxyDestination implements HttpDestination
     static final String TENANT_SUBDOMAIN_HEADER_KEY = "x-tenant-subdomain";
     static final String TENANT_ID_HEADER_KEY = "x-tenant-id";
     static final String FRAGMENT_OPTIONAL_HEADER_KEY = "x-fragment-optional";
+    static final String DESTINATION_LEVEL_HEADER_KEY = "x-destination-level";
+    static final String FRAGMENT_LEVEL_HEADER_KEY = "x-fragment-level";
     static final String TOKEN_SERVICE_TENANT_HEADER_KEY = "x-token-service-tenant";
     static final String CLIENT_ASSERTION_HEADER_KEY = "x-client-assertion";
     static final String CLIENT_ASSERTION_TYPE_HEADER_KEY = "x-client-assertion-type";
@@ -52,7 +54,7 @@ public class TransparentProxyDestination implements HttpDestination
     static final String CHAIN_VAR_SUBJECT_TOKEN_TYPE_HEADER_KEY = "x-chain-var-subjectTokenType";
     static final String CHAIN_VAR_SAML_PROVIDER_DESTINATION_NAME_HEADER_KEY = "x-chain-var-samlProviderDestinationName";
     static final String TENANT_ID_AND_TENANT_SUBDOMAIN_BOTH_PASSED_ERROR_MESSAGE =
-        "Tenant id and tenant subdomain cannot be passed at the same time.";
+            "Tenant id and tenant subdomain cannot be passed at the same time.";
 
     @Delegate
     private final DestinationProperties baseProperties;
@@ -68,23 +70,23 @@ public class TransparentProxyDestination implements HttpDestination
     private final ImmutableList<DestinationHeaderProvider> headerProvidersFromClassLoading;
 
     private TransparentProxyDestination(
-        @Nonnull final DestinationProperties baseProperties,
-        @Nullable final List<Header> customHeaders,
-        @Nullable final List<DestinationHeaderProvider> customHeaderProviders )
+            @Nonnull final DestinationProperties baseProperties,
+            @Nullable final List<Header> customHeaders,
+            @Nullable final List<DestinationHeaderProvider> customHeaderProviders )
     {
         this.baseProperties = baseProperties;
         this.customHeaders =
-            customHeaders != null ? ImmutableList.<Header> builder().addAll(customHeaders).build() : ImmutableList.of();
+                customHeaders != null ? ImmutableList.<Header> builder().addAll(customHeaders).build() : ImmutableList.of();
 
         final Collection<DestinationHeaderProvider> headerProvidersFromClassLoading =
-            FacadeLocator.getFacades(DestinationHeaderProvider.class);
+                FacadeLocator.getFacades(DestinationHeaderProvider.class);
         this.headerProvidersFromClassLoading =
-            ImmutableList.<DestinationHeaderProvider> builder().addAll(headerProvidersFromClassLoading).build();
+                ImmutableList.<DestinationHeaderProvider> builder().addAll(headerProvidersFromClassLoading).build();
 
         this.customHeaderProviders =
-            customHeaderProviders != null
-                ? ImmutableList.<DestinationHeaderProvider> builder().addAll(customHeaderProviders).build()
-                : ImmutableList.of();
+                customHeaderProviders != null
+                        ? ImmutableList.<DestinationHeaderProvider> builder().addAll(customHeaderProviders).build()
+                        : ImmutableList.of();
 
     }
 
@@ -103,18 +105,18 @@ public Collection<Header> getHeaders( @Nonnull final URI requestUri )
 
         allHeaders.addAll(customHeaders);
         allHeaders
-            .addAll(
-                DefaultHttpDestination
-                    .getHeadersFromHeaderProviders(
-                        this,
-                        requestUri,
-                        customHeaderProviders,
-                        headerProvidersFromClassLoading));
+                .addAll(
+                        DefaultHttpDestination
+                                .getHeadersFromHeaderProviders(
+                                        this,
+                                        requestUri,
+                                        customHeaderProviders,
+                                        headerProvidersFromClassLoading));
 
         // Automatically add tenant id if not already present
         TenantAccessor.tryGetCurrentTenant().onSuccess(tenant -> {
             if( !containsHeader(allHeaders, TENANT_ID_HEADER_KEY)
-                && !containsHeader(allHeaders, TENANT_SUBDOMAIN_HEADER_KEY) ) {
+                    && !containsHeader(allHeaders, TENANT_SUBDOMAIN_HEADER_KEY) ) {
                 allHeaders.add(new Header(TENANT_ID_HEADER_KEY, tenant.getTenantId()));
             }
         });
@@ -215,9 +217,9 @@ public boolean equals( @Nullable final Object o )
 
         final TransparentProxyDestination that = (TransparentProxyDestination) o;
         return new EqualsBuilder()
-            .append(baseProperties, that.baseProperties)
-            .append(customHeaders, that.customHeaders)
-            .isEquals();
+                .append(baseProperties, that.baseProperties)
+                .append(customHeaders, that.customHeaders)
+                .isEquals();
     }
 
     @Override
@@ -646,7 +648,7 @@ private DynamicBuilder( @Nonnull final String destinationName, @Nonnull final St
         {
             if( destinationName.isEmpty() ) {
                 throw new IllegalArgumentException(
-                    "The 'destinationName' property is required for dynamic destinations but was not set.");
+                        "The 'destinationName' property is required for dynamic destinations but was not set.");
             }
 
             this.header(DESTINATION_NAME_HEADER_KEY, destinationName);
@@ -673,6 +675,34 @@ public DynamicBuilder fragmentName( @Nonnull final String fragmentName )
             return header(new Header(FRAGMENT_NAME_HEADER_KEY, fragmentName));
         }
 
+        /**
+         * Sets the destination level for the dynamic destination. See
+         * https://help.sap.com/docs/connectivity/sap-btp-connectivity-cf/dynamic-lookup-of-destinations
+         *
+         * @param destinationLevel
+         *            The level of the destination to use.
+         * @return This builder instance for method chaining.
+         */
+        @Nonnull
+        public DynamicBuilder destinationLevel( @Nonnull final String destinationLevel )
+        {
+            return header(new Header(DESTINATION_LEVEL_HEADER_KEY, destinationLevel));
+        }
+
+        /**
+         * Sets the fragment level for the dynamic destination. See
+         * https://help.sap.com/docs/connectivity/sap-btp-connectivity-cf/dynamic-lookup-of-destinations
+         *
+         * @param fragmentLevel
+         *            The level of the fragment to use.
+         * @return This builder instance for method chaining.
+         */
+        @Nonnull
+        public DynamicBuilder fragmentLevel( @Nonnull final String fragmentLevel )
+        {
+            return header(new Header(FRAGMENT_LEVEL_HEADER_KEY, fragmentLevel));
+        }
+
         /**
          * Sets the fragment optional flag for the dynamic destination. See
          * https://help.sap.com/docs/connectivity/sap-btp-connectivity-cf/dynamic-lookup-of-destinations