HDDS-14916. Add a code generator for implementing invokeLocal(..).

[szetszwo]

What changes were proposed in this pull request?

Given an interface, generate the code for all the local calls.

What is the link to the Apache JIRA

HDDS-14916

How was this patch tested?

Tested manually.

[szetszwo]

Output for DeletedBlockLogStateManager:

  // Code generated for DeletedBlockLogStateManager.  Do not modify.
  @SuppressWarnings("unchecked")
  @Override
  public Object invokeLocal(String methodName, Object[] params) throws Exception {
    switch (methodName) {
      case "onFlush": {
        impl.onFlush();
        return null;
      }
      case "addTransactionsToDB": {
        final ArrayList arg0 = params.length > 0 ? (ArrayList) params[0] : null;
        final DeletedBlocksTransactionSummary arg1 = params.length > 1 ? (DeletedBlocksTransactionSummary) params[1] : null;
        impl.addTransactionsToDB(arg0, arg1);
        return null;
      }
      case "removeTransactionsFromDB": {
        final ArrayList arg0 = params.length > 0 ? (ArrayList) params[0] : null;
        final DeletedBlocksTransactionSummary arg1 = params.length > 1 ? (DeletedBlocksTransactionSummary) params[1] : null;
        impl.removeTransactionsFromDB(arg0, arg1);
        return null;
      }
      case "getReadOnlyIterator": {
        return impl.getReadOnlyIterator();
      }
      case "reinitialize": {
        final Table arg0 = params.length > 0 ? (Table) params[0] : null;
        final Table arg1 = params.length > 1 ? (Table) params[1] : null;
        impl.reinitialize(arg0, arg1);
        return null;
      }
    }
    throw new IllegalArgumentException("Method not found: " + methodName);
  }

[Russole]

Thanks @szetszwo for working on this. LGTM!

[adoroszlai]

Thanks @szetszwo for the patch.

For the record, the tool can be run from CLI as:

cd hadoop-ozone/dist/target/ozone-2.2.0-SNAPSHOT
java -cp $(echo share/ozone/lib/*.jar | sed 's/ /:/g') org.apache.hadoop.hdds.scm.block.DeletedBlockLogStateManager

[adoroszlai]

switch and case should be on the same level to satisfy this (unfortunate) checkstyle rule:

ozone/hadoop-hdds/dev-support/checkstyle/checkstyle.xml

Line 200 in 64db655

<property name="caseIndent" value="0"/>

(We can work on getting rid of the rule separately, since it needs lots of code changes.)

[adoroszlai]

I think we should sort methods alphabetically. This would stabilize order, reducing diff after regenerating code when the interface is changed.

[szetszwo]

@Russole , @adoroszlai , thanks for reviewing this!

• Fixed the case indentation checkstyple problem.
• Sorted the methods in switch.
• It can generate the entire class now.

/** Code generated for DeletedBlockLogStateManager.  Do not modify. */
public class DeletedBlockLogStateManagerInvoker implements ScmInvoker<DeletedBlockLogStateManager> {
  private final DeletedBlockLogStateManager impl;

  public DeletedBlockLogStateManagerInvoker(DeletedBlockLogStateManager impl) {
    this.impl = impl;
  }

  @Override
  public RequestType getType() {
    return RequestType.BLOCK;
  }

  @Override
  public Class<DeletedBlockLogStateManager> getApi() {
    return DeletedBlockLogStateManager.class;
  }

  @Override
  public DeletedBlockLogStateManager getImpl() {
    return impl;
  }

  @SuppressWarnings("unchecked")
  @Override
  public Object invokeLocal(String methodName, Object[] params) throws Exception {
    switch (methodName) {
    case "addTransactionsToDB":
      final ArrayList arg0 = params.length > 0 ? (ArrayList) params[0] : null;
      final DeletedBlocksTransactionSummary arg1 = params.length > 1 ? (DeletedBlocksTransactionSummary) params[1] : null;
      impl.addTransactionsToDB(arg0, arg1);
      return null;

    case "getReadOnlyIterator":
      return impl.getReadOnlyIterator();

    case "onFlush":
      impl.onFlush();
      return null;

    case "reinitialize":
      final Table arg2 = params.length > 0 ? (Table) params[0] : null;
      final Table arg3 = params.length > 1 ? (Table) params[1] : null;
      impl.reinitialize(arg2, arg3);
      return null;

    case "removeTransactionsFromDB":
      final ArrayList arg4 = params.length > 0 ? (ArrayList) params[0] : null;
      final DeletedBlocksTransactionSummary arg5 = params.length > 1 ? (DeletedBlocksTransactionSummary) params[1] : null;
      impl.removeTransactionsFromDB(arg4, arg5);
      return null;

    default:
      throw new IllegalArgumentException("Method not found: " + methodName + " in DeletedBlockLogStateManager");
    }
  }
}