Restore ConnectionSetupPayload as abstract class (#785)

Another follow-up fix for commit 0ac54d4. Changing ConnectionSetupPayload
from abstract class to interface is problematic when framework code
compiled against newer RSocket is used in an application on existing
version.

ConnectionSetupPayload is now an abstract class again but
DefaultConnectionSetupPayload remains in the "core" sub-package to avoid
the package cycle with "frame".

See gh-778

Signed-off-by: Rossen Stoyanchev <rstoyanchev@pivotal.io>

Author: rstoyanchev

rsocket-core/src/main/java/io/rsocket/ConnectionSetupPayload.java

@@ -13,31 +13,60 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package io.rsocket;
 
 import io.netty.buffer.ByteBuf;
-import io.netty.util.ReferenceCounted;
+import io.netty.util.AbstractReferenceCounted;
+import io.rsocket.core.DefaultConnectionSetupPayload;
 import javax.annotation.Nullable;
 
 /**
  * Exposes information from the {@code SETUP} frame to a server, as well as to client responders.
  */
-public interface ConnectionSetupPayload extends ReferenceCounted, Payload {
+public abstract class ConnectionSetupPayload extends AbstractReferenceCounted implements Payload {
 
-  String metadataMimeType();
+  public abstract String metadataMimeType();
 
-  String dataMimeType();
+  public abstract String dataMimeType();
 
-  int keepAliveInterval();
+  public abstract int keepAliveInterval();
 
-  int keepAliveMaxLifetime();
+  public abstract int keepAliveMaxLifetime();
 
-  int getFlags();
+  public abstract int getFlags();
 
-  boolean willClientHonorLease();
+  public abstract boolean willClientHonorLease();
 
-  boolean isResumeEnabled();
+  public abstract boolean isResumeEnabled();
 
   @Nullable
-  ByteBuf resumeToken();
+  public abstract ByteBuf resumeToken();
+
+  @Override
+  public ConnectionSetupPayload retain() {
+    super.retain();
+    return this;
+  }
+
+  @Override
+  public ConnectionSetupPayload retain(int increment) {
+    super.retain(increment);
+    return this;
+  }
+
+  @Override
+  public abstract ConnectionSetupPayload touch();
+
+  /**
+   * Create a {@code ConnectionSetupPayload}.
+   *
+   * @deprecated as of 1.0 RC7. Please, use {@link
+   *     DefaultConnectionSetupPayload#DefaultConnectionSetupPayload(ByteBuf)
+   *     DefaultConnectionSetupPayload} constructor.
+   */
+  @Deprecated
+  public static ConnectionSetupPayload create(final ByteBuf setupFrame) {
+    return new DefaultConnectionSetupPayload(setupFrame);
+  }
 }

rsocket-core/src/main/java/io/rsocket/core/DefaultConnectionSetupPayload.java

@@ -17,14 +17,15 @@
 package io.rsocket.core;
 
 import io.netty.buffer.ByteBuf;
-import io.netty.util.AbstractReferenceCounted;
 import io.rsocket.ConnectionSetupPayload;
 import io.rsocket.frame.FrameHeaderFlyweight;
 import io.rsocket.frame.SetupFrameFlyweight;
 
-/** Default implementation of {@link ConnectionSetupPayload}. */
-class DefaultConnectionSetupPayload extends AbstractReferenceCounted
-    implements ConnectionSetupPayload {
+/**
+ * Default implementation of {@link ConnectionSetupPayload}. Primarily for internal use within
+ * RSocket Java but may be created in an application, e.g. for testing purposes.
+ */
+public class DefaultConnectionSetupPayload extends ConnectionSetupPayload {
 
   private final ByteBuf setupFrame;
 
@@ -33,30 +34,28 @@ public DefaultConnectionSetupPayload(ByteBuf setupFrame) {
   }
 
   @Override
-  public ConnectionSetupPayload retain() {
-    super.retain();
-    return this;
+  public boolean hasMetadata() {
+    return FrameHeaderFlyweight.hasMetadata(setupFrame);
   }
 
   @Override
-  public ConnectionSetupPayload retain(int increment) {
-    super.retain(increment);
-    return this;
+  public ByteBuf sliceMetadata() {
+    return SetupFrameFlyweight.metadata(setupFrame);
   }
 
   @Override
-  public boolean hasMetadata() {
-    return FrameHeaderFlyweight.hasMetadata(setupFrame);
+  public ByteBuf sliceData() {
+    return SetupFrameFlyweight.data(setupFrame);
   }
 
   @Override
-  public int keepAliveInterval() {
-    return SetupFrameFlyweight.keepAliveInterval(setupFrame);
+  public ByteBuf data() {
+    return sliceData();
   }
 
   @Override
-  public int keepAliveMaxLifetime() {
-    return SetupFrameFlyweight.keepAliveMaxLifetime(setupFrame);
+  public ByteBuf metadata() {
+    return sliceMetadata();
   }
 
   @Override
@@ -69,6 +68,16 @@ public String dataMimeType() {
     return SetupFrameFlyweight.dataMimeType(setupFrame);
   }
 
+  @Override
+  public int keepAliveInterval() {
+    return SetupFrameFlyweight.keepAliveInterval(setupFrame);
+  }
+
+  @Override
+  public int keepAliveMaxLifetime() {
+    return SetupFrameFlyweight.keepAliveMaxLifetime(setupFrame);
+  }
+
   @Override
   public int getFlags() {
     return FrameHeaderFlyweight.flags(setupFrame);
@@ -105,24 +114,4 @@ public ConnectionSetupPayload touch(Object hint) {
   protected void deallocate() {
     setupFrame.release();
   }
-
-  @Override
-  public ByteBuf sliceMetadata() {
-    return SetupFrameFlyweight.metadata(setupFrame);
-  }
-
-  @Override
-  public ByteBuf sliceData() {
-    return SetupFrameFlyweight.data(setupFrame);
-  }
-
-  @Override
-  public ByteBuf data() {
-    return sliceData();
-  }
-
-  @Override
-  public ByteBuf metadata() {
-    return sliceMetadata();
-  }
 }