THRIFT-5345: Allow the ServerContext to be Unwrapped Programmatically
Client: Java
Patch: David Mollitor
diff --git a/lib/java/src/org/apache/thrift/server/ServerContext.java b/lib/java/src/org/apache/thrift/server/ServerContext.java
index 9b0b99e..b7c587f 100644
--- a/lib/java/src/org/apache/thrift/server/ServerContext.java
+++ b/lib/java/src/org/apache/thrift/server/ServerContext.java
@@ -18,9 +18,32 @@
*/
/**
- * Interface for storing server's connection context
+ * Interface for storing server's connection context.
*/
-
package org.apache.thrift.server;
-public interface ServerContext {}
+public interface ServerContext {
+
+ /**
+ * Returns an object that implements the given interface to allow access to
+ * application specific contexts.
+ *
+ * @param iface A Class defining an interface that the result must implement
+ * @return an object that implements the interface
+ * @throws RuntimeException If the context cannot be unwrapped to the provided
+ * class
+ */
+ <T> T unwrap(Class<T> iface);
+
+ /**
+ * Returns true if this server context is a wrapper for the provided
+ * application specific context interface argument or returns false otherwise.
+ *
+ * @param iface a Class defining the underlying context
+ * @return true if this implements the interface can be unwrapped to the
+ * provided class
+ * @throws RuntimeException if an error occurs while determining whether the
+ * provided class can be unwrapped from this context.
+ */
+ boolean isWrapperFor(Class<?> iface);
+}
diff --git a/lib/java/test/org/apache/thrift/test/TestServer.java b/lib/java/test/org/apache/thrift/test/TestServer.java
index 02e8ad7..386f2b6 100644
--- a/lib/java/test/org/apache/thrift/test/TestServer.java
+++ b/lib/java/test/org/apache/thrift/test/TestServer.java
@@ -81,6 +81,24 @@
this.connectionId = connectionId;
}
+ @Override
+ public <T> T unwrap(Class<T> iface) {
+ try {
+ if (isWrapperFor(iface)) {
+ return iface.cast(this);
+ } else {
+ throw new RuntimeException("The context is not a wrapper for " + iface.getName());
+ }
+ } catch (Exception e) {
+ throw new RuntimeException("The context is not a wrapper and does not implement the interface");
+ }
+ }
+
+ @Override
+ public boolean isWrapperFor(Class<?> iface) {
+ return iface.isInstance(this);
+ }
+
}
static class TestServerEventHandler implements TServerEventHandler {
@@ -99,12 +117,12 @@
}
public void deleteContext(ServerContext serverContext, TProtocol input, TProtocol output) {
- TestServerContext ctx = (TestServerContext)serverContext;
+ TestServerContext ctx = serverContext.unwrap(TestServerContext.class);
System.out.println("TServerEventHandler.deleteContext - connection #"+ctx.getConnectionId()+" terminated");
}
public void processContext(ServerContext serverContext, TTransport inputTransport, TTransport outputTransport) {
- TestServerContext ctx = (TestServerContext)serverContext;
+ TestServerContext ctx = serverContext.unwrap(TestServerContext.class);
System.out.println("TServerEventHandler.processContext - connection #"+ctx.getConnectionId()+" is ready to process next request");
}