[FAB-13795] Contract definition

Change-Id: I848cd04986a3c3d70d7d1930021c7bfa8075d51e
Signed-off-by: gennady <[email protected]>

Author: gennadylaventman

fabric-chaincode-shim/src/main/java/org/hyperledger/fabric/contract/ContractInterface.java

@@ -0,0 +1,44 @@
+/*
+Copyright IBM Corp., DTCC All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package org.hyperledger.fabric.contract;
+
+import org.hyperledger.fabric.shim.ChaincodeStub;
+
+/**
+ * Interface all contracts should implement
+ */
+public interface ContractInterface {
+    /**
+     * Returns instance of context associated with current invocation
+     * @return
+     */
+    default Context getContext() { throw new IllegalStateException("getContext default implementation can't be directly invoked"); }
+
+    /**
+     * Create context from {@link ChaincodeStub}, default impl provided, but can be overwritten by contract
+     * @param stub
+     * @return
+     */
+    default Context createContext(ChaincodeStub stub) { return ContextFactory.getInstance().createContext(stub); }
+
+    /**
+     * Invoked once method for transaction not exist in contract
+     */
+    default void unknownTransaction() {
+        throw new IllegalStateException("Undefined contract method called");
+    }
+
+    /**
+     * Invoke before each transaction method
+     */
+    default void beforeTransaction() {}
+
+    /**
+     * Invoke after each transaction method
+     */
+    default void afterTransaction() {}
+}

fabric-chaincode-shim/src/main/java/org/hyperledger/fabric/contract/annotation/Contract.java

@@ -0,0 +1,25 @@
+/*
+Copyright IBM Corp., DTCC All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package org.hyperledger.fabric.contract.annotation;
+
+import io.swagger.v3.oas.annotations.info.Info;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+/**
+ * Class level annotation that identifies this class as being a contract.
+ */
+@Retention(RUNTIME)
+@Target(ElementType.TYPE)
+public @interface Contract {
+    Info info();
+    String namespace() default "";
+}

fabric-chaincode-shim/src/test/java/org/hyperledger/fabric/contract/ContractInterfaceTest.java

@@ -0,0 +1,47 @@
+/*
+Copyright IBM Corp. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+package org.hyperledger.fabric.contract;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import static org.hamcrest.Matchers.*;
+import static org.junit.Assert.*;
+
+public class ContractInterfaceTest {
+    @Rule
+    public ExpectedException thrown = ExpectedException.none();
+
+    @Test
+    public void getContext() {
+        thrown.expect(IllegalStateException.class);
+        thrown.expectMessage("getContext default implementation can't be directly invoked");
+        new ContractInterface() {}.getContext();
+    }
+
+    @Test
+    public void createContext() {
+        assertThat((new ContractInterface(){}).createContext(new ChaincodeStubNaiveImpl()), is(instanceOf(Context.class)));
+    }
+
+    @Test
+    public void unknownTransaction() {
+        thrown.expect(IllegalStateException.class);
+        thrown.expectMessage("Undefined contract method called");
+        new ContractInterface() {}.unknownTransaction();
+    }
+
+    @Test
+    public void beforeTransaction() {
+        new ContractInterface() {}.beforeTransaction();
+    }
+
+    @Test
+    public void afterTransaction() {
+        new ContractInterface() {}.afterTransaction();
+    }
+}