Updates tutorial to reflect new template structure. Clean-up. (#4216)

* Initial improvements.

* Updates tutorials.

* Missing imports.

* Addresses review feedback.

docs/source/example-code/src/main/java/net/corda/docs/java/tutorial/helloworld/IOUFlow.java

@@ -2,16 +2,19 @@ package net.corda.docs.java.tutorial.helloworld;
 
 import co.paralleluniverse.fibers.Suspendable;
 import com.template.TemplateContract;
-import net.corda.core.flows.*;
+import net.corda.core.flows.FlowException;
+import net.corda.core.flows.FlowLogic;
+import net.corda.core.flows.InitiatingFlow;
+import net.corda.core.flows.StartableByRPC;
+import net.corda.core.utilities.ProgressTracker;
 
 // DOCSTART 01
 // Add these imports:
 import net.corda.core.contracts.Command;
-import net.corda.core.contracts.CommandData;
+import net.corda.core.flows.FinalityFlow;
 import net.corda.core.identity.Party;
 import net.corda.core.transactions.SignedTransaction;
 import net.corda.core.transactions.TransactionBuilder;
-import net.corda.core.utilities.ProgressTracker;
 
 // Replace Initiator's definition with:
 @InitiatingFlow
@@ -46,13 +49,12 @@ public class IOUFlow extends FlowLogic<Void> {
 
         // We create the transaction components.
         IOUState outputState = new IOUState(iouValue, getOurIdentity(), otherParty);
-        CommandData cmdType = new TemplateContract.Commands.Action();
-        Command cmd = new Command<>(cmdType, getOurIdentity().getOwningKey());
+        Command command = new Command<>(new TemplateContract.Commands.Action(), getOurIdentity().getOwningKey());
 
         // We create a transaction builder and add the components.
         TransactionBuilder txBuilder = new TransactionBuilder(notary)
                 .addOutputState(outputState, TemplateContract.ID)
-                .addCommand(cmd);
+                .addCommand(command);
 
         // Signing the transaction.
         SignedTransaction signedTx = getServiceHub().signInitialTransaction(txBuilder);

docs/source/example-code/src/main/java/net/corda/docs/java/tutorial/helloworld/IOUState.java

@@ -2,11 +2,11 @@ package net.corda.docs.java.tutorial.helloworld;
 
 import net.corda.core.contracts.ContractState;
 import net.corda.core.identity.AbstractParty;
+import java.util.Arrays;
 import java.util.List;
 
 // DOCSTART 01
-// Add these imports:
-import com.google.common.collect.ImmutableList;
+// Add this import:
 import net.corda.core.identity.Party;
 
 // Replace TemplateState's definition with:
@@ -35,7 +35,7 @@ public class IOUState implements ContractState {
 
     @Override
     public List<AbstractParty> getParticipants() {
-        return ImmutableList.of(lender, borrower);
+        return Arrays.asList(lender, borrower);
     }
 }
 // DOCEND 01

docs/source/example-code/src/main/java/net/corda/docs/java/tutorial/twoparty/IOUContract.java

@@ -6,15 +6,14 @@ import net.corda.core.transactions.LedgerTransaction;
 
 // DOCSTART 01
 // Add these imports:
-import com.google.common.collect.ImmutableList;
 import net.corda.core.contracts.CommandWithParties;
 import net.corda.core.identity.Party;
 
 import java.security.PublicKey;
+import java.util.Arrays;
 import java.util.List;
 
 import static net.corda.core.contracts.ContractsDSL.requireSingleCommand;
-import static net.corda.core.contracts.ContractsDSL.requireThat;
 
 // Replace TemplateContract's definition with:
 public class IOUContract implements Contract {
@@ -28,26 +27,29 @@ public class IOUContract implements Contract {
     public void verify(LedgerTransaction tx) {
         final CommandWithParties<IOUContract.Create> command = requireSingleCommand(tx.getCommands(), IOUContract.Create.class);
 
-        requireThat(check -> {
-            // Constraints on the shape of the transaction.
-            check.using("No inputs should be consumed when issuing an IOU.", tx.getInputs().isEmpty());
-            check.using("There should be one output state of type IOUState.", tx.getOutputs().size() == 1);
+        // Constraints on the shape of the transaction.
+        if (!tx.getInputs().isEmpty())
+            throw new IllegalArgumentException("No inputs should be consumed when issuing an IOU.");
+        if (!(tx.getOutputs().size() == 1))
+            throw new IllegalArgumentException("There should be one output state of type IOUState.");
 
-            // IOU-specific constraints.
-            final IOUState out = tx.outputsOfType(IOUState.class).get(0);
-            final Party lender = out.getLender();
-            final Party borrower = out.getBorrower();
-            check.using("The IOU's value must be non-negative.", out.getValue() > 0);
-            check.using("The lender and the borrower cannot be the same entity.", lender != borrower);
+        // IOU-specific constraints.
+        final IOUState output = tx.outputsOfType(IOUState.class).get(0);
+        final Party lender = output.getLender();
+        final Party borrower = output.getBorrower();
+        if (output.getValue() <= 0)
+            throw new IllegalArgumentException("The IOU's value must be non-negative.");
+        if (lender.equals(borrower))
+            throw new IllegalArgumentException("The lender and the borrower cannot be the same entity.");
 
-            // Constraints on the signers.
-            final List<PublicKey> signers = command.getSigners();
-            check.using("There must be two signers.", signers.size() == 2);
-            check.using("The borrower and lender must be signers.", signers.containsAll(
-                    ImmutableList.of(borrower.getOwningKey(), lender.getOwningKey())));
+        // Constraints on the signers.
+        final List<PublicKey> requiredSigners = command.getSigners();
+        final List<PublicKey> expectedSigners = Arrays.asList(borrower.getOwningKey(), lender.getOwningKey());
+        if (requiredSigners.size() != 2)
+            throw new IllegalArgumentException("There must be two signers.");
+        if (!(requiredSigners.containsAll(expectedSigners)))
+            throw new IllegalArgumentException("The borrower and lender must be signers.");
 
-            return null;
-        });
     }
 }
 // DOCEND 01

docs/source/example-code/src/main/java/net/corda/docs/java/tutorial/twoparty/IOUFlow.java

@@ -2,9 +2,7 @@ package net.corda.docs.java.tutorial.twoparty;
 
 // DOCSTART 01
 import co.paralleluniverse.fibers.Suspendable;
-import com.google.common.collect.ImmutableList;
 import net.corda.core.contracts.Command;
-import net.corda.core.contracts.StateAndContract;
 import net.corda.core.flows.*;
 import net.corda.core.identity.Party;
 import net.corda.core.transactions.SignedTransaction;
@@ -12,6 +10,7 @@ import net.corda.core.transactions.TransactionBuilder;
 import net.corda.core.utilities.ProgressTracker;
 
 import java.security.PublicKey;
+import java.util.Arrays;
 import java.util.List;
 // DOCEND 01
 
@@ -42,22 +41,19 @@ public class IOUFlow extends FlowLogic<Void> {
     @Suspendable
     @Override
     public Void call() throws FlowException {
+        // DOCSTART 02
         // We retrieve the notary identity from the network map.
         Party notary = getServiceHub().getNetworkMapCache().getNotaryIdentities().get(0);
 
-        // DOCSTART 02
-        // We create a transaction builder.
-        TransactionBuilder txBuilder = new TransactionBuilder();
-        txBuilder.setNotary(notary);
-
         // We create the transaction components.
         IOUState outputState = new IOUState(iouValue, getOurIdentity(), otherParty);
-        StateAndContract outputContractAndState = new StateAndContract(outputState, IOUContract.ID);
-        List<PublicKey> requiredSigners = ImmutableList.of(getOurIdentity().getOwningKey(), otherParty.getOwningKey());
-        Command cmd = new Command<>(new IOUContract.Create(), requiredSigners);
+        List<PublicKey> requiredSigners = Arrays.asList(getOurIdentity().getOwningKey(), otherParty.getOwningKey());
+        Command command = new Command<>(new IOUContract.Create(), requiredSigners);
 
-        // We add the items to the builder.
-        txBuilder.withItems(outputContractAndState, cmd);
+        // We create a transaction builder and add the components.
+        TransactionBuilder txBuilder = new TransactionBuilder(notary)
+                .addOutputState(outputState, IOUContract.ID)
+                .addCommand(command);
 
         // Verifying the transaction.
         txBuilder.verify(getServiceHub());
@@ -70,7 +66,7 @@ public class IOUFlow extends FlowLogic<Void> {
 
         // Obtaining the counterparty's signature.
         SignedTransaction fullySignedTx = subFlow(new CollectSignaturesFlow(
-                signedTx, ImmutableList.of(otherPartySession), CollectSignaturesFlow.tracker()));
+                signedTx, Arrays.asList(otherPartySession), CollectSignaturesFlow.tracker()));
 
         // Finalising the transaction.
         subFlow(new FinalityFlow(fullySignedTx));

docs/source/example-code/src/main/java/net/corda/docs/java/tutorial/twoparty/IOUState.java

@@ -1,10 +1,10 @@
 package net.corda.docs.java.tutorial.twoparty;
 
-import com.google.common.collect.ImmutableList;
 import net.corda.core.contracts.ContractState;
 import net.corda.core.identity.AbstractParty;
 import net.corda.core.identity.Party;
 
+import java.util.Arrays;
 import java.util.List;
 
 public class IOUState implements ContractState {
@@ -32,6 +32,6 @@ public class IOUState implements ContractState {
 
     @Override
     public List<AbstractParty> getParticipants() {
-        return ImmutableList.of(lender, borrower);
+        return Arrays.asList(lender, borrower);
     }
 }

docs/source/example-code/src/main/kotlin/net/corda/docs/kotlin/tutorial/helloworld/IOUFlow.kt

@@ -8,13 +8,13 @@ import net.corda.core.flows.FinalityFlow
 import net.corda.core.flows.FlowLogic
 import net.corda.core.flows.InitiatingFlow
 import net.corda.core.flows.StartableByRPC
+import net.corda.core.utilities.ProgressTracker
 
 // DOCSTART 01
 // Add these imports:
 import net.corda.core.contracts.Command
 import net.corda.core.identity.Party
 import net.corda.core.transactions.TransactionBuilder
-import net.corda.core.utilities.ProgressTracker
 
 // Replace Initiator's definition with:
 @InitiatingFlow
@@ -33,12 +33,12 @@ class IOUFlow(val iouValue: Int,
 
         // We create the transaction components.
         val outputState = IOUState(iouValue, ourIdentity, otherParty)
-        val cmd = Command(TemplateContract.Commands.Action(), ourIdentity.owningKey)
+        val command = Command(TemplateContract.Commands.Action(), ourIdentity.owningKey)
 
         // We create a transaction builder and add the components.
         val txBuilder = TransactionBuilder(notary = notary)
                 .addOutputState(outputState, TemplateContract.ID)
-                .addCommand(cmd)
+                .addCommand(command)
 
         // We sign the transaction.
         val signedTx = serviceHub.signInitialTransaction(txBuilder)

docs/source/example-code/src/main/kotlin/net/corda/docs/kotlin/tutorial/helloworld/IOUState.kt

@@ -5,7 +5,7 @@ package net.corda.docs.kotlin.tutorial.helloworld
 import net.corda.core.contracts.ContractState
 
 // DOCSTART 01
-// Add these imports:
+// Add this import:
 import net.corda.core.identity.Party
 
 // Replace TemplateState's definition with:

docs/source/example-code/src/main/kotlin/net/corda/docs/kotlin/tutorial/twoparty/IOUContract.kt

@@ -5,7 +5,7 @@ import net.corda.core.contracts.Contract
 import net.corda.core.transactions.LedgerTransaction
 
 // DOCSTART 01
-// Add these imports:
+// Add this import:
 import net.corda.core.contracts.*
 
 class IOUContract : Contract {
@@ -25,14 +25,14 @@ class IOUContract : Contract {
             "There should be one output state of type IOUState." using (tx.outputs.size == 1)
 
             // IOU-specific constraints.
-            val out = tx.outputsOfType<IOUState>().single()
-            "The IOU's value must be non-negative." using (out.value > 0)
-            "The lender and the borrower cannot be the same entity." using (out.lender != out.borrower)
+            val output = tx.outputsOfType<IOUState>().single()
+            "The IOU's value must be non-negative." using (output.value > 0)
+            "The lender and the borrower cannot be the same entity." using (output.lender != output.borrower)
 
             // Constraints on the signers.
+            val expectedSigners = listOf(output.borrower.owningKey, output.lender.owningKey)
             "There must be two signers." using (command.signers.toSet().size == 2)
-            "The borrower and lender must be signers." using (command.signers.containsAll(listOf(
-                    out.borrower.owningKey, out.lender.owningKey)))
+            "The borrower and lender must be signers." using (command.signers.containsAll(expectedSigners))
         }
     }
 }

docs/source/example-code/src/main/kotlin/net/corda/docs/kotlin/tutorial/twoparty/IOUFlow.kt

@@ -5,7 +5,6 @@ package net.corda.docs.kotlin.tutorial.twoparty
 // DOCSTART 01
 import co.paralleluniverse.fibers.Suspendable
 import net.corda.core.contracts.Command
-import net.corda.core.contracts.StateAndContract
 import net.corda.core.flows.CollectSignaturesFlow
 import net.corda.core.flows.FinalityFlow
 import net.corda.core.flows.FlowLogic
@@ -27,20 +26,18 @@ class IOUFlow(val iouValue: Int,
     /** The flow logic is encapsulated within the call() method. */
     @Suspendable
     override fun call() {
+        // DOCSTART 02
         // We retrieve the notary identity from the network map.
         val notary = serviceHub.networkMapCache.notaryIdentities[0]
 
-        // DOCSTART 02
-        // We create a transaction builder.
-        val txBuilder = TransactionBuilder(notary = notary)
-
         // We create the transaction components.
         val outputState = IOUState(iouValue, ourIdentity, otherParty)
-        val outputContractAndState = StateAndContract(outputState, IOUContract.ID)
-        val cmd = Command(IOUContract.Create(), listOf(ourIdentity.owningKey, otherParty.owningKey))
+        val command = Command(IOUContract.Create(), listOf(ourIdentity.owningKey, otherParty.owningKey))
 
-        // We add the items to the builder.
-        txBuilder.withItems(outputContractAndState, cmd)
+        // We create a transaction builder and add the components.
+        val txBuilder = TransactionBuilder(notary = notary)
+                .addOutputState(outputState, IOUContract.ID)
+                .addCommand(command)
 
         // Verifying the transaction.
         txBuilder.verify(serviceHub)

docs/source/example-code/src/main/kotlin/net/corda/docs/kotlin/tutorial/twoparty/IOUFlowResponder.kt

@@ -3,10 +3,7 @@
 package net.corda.docs.kotlin.tutorial.twoparty
 
 import co.paralleluniverse.fibers.Suspendable
-import net.corda.core.flows.FlowLogic
-import net.corda.core.flows.FlowSession
-import net.corda.core.flows.InitiatedBy
-import net.corda.core.flows.SignTransactionFlow
+import net.corda.core.flows.*
 import net.corda.docs.kotlin.tutorial.helloworld.IOUFlow
 import net.corda.docs.kotlin.tutorial.helloworld.IOUState