feat: async connection api

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AbstractBaseConnection.java

@@ -0,0 +1,37 @@
+package com.google.cloud.spanner.connection;
+
+import com.google.cloud.spanner.connection.ConnectionImpl.LeakedConnectionException;
+import org.threeten.bp.Instant;
+
+abstract class AbstractBaseConnection implements BaseConnection {
+  private static final String CLOSED_ERROR_MSG = "This connection is closed";
+  private static final String ONLY_ALLOWED_IN_AUTOCOMMIT =
+      "This method may only be called while in autocommit mode";
+  private static final String NOT_ALLOWED_IN_AUTOCOMMIT =
+      "This method may not be called while in autocommit mode";
+
+  /**
+   * Exception that is used to register the stacktrace of the code that opened a {@link Connection}.
+   * This exception is logged if the application closes without first closing the connection.
+   */
+  static class LeakedConnectionException extends RuntimeException {
+    private static final long serialVersionUID = 7119433786832158700L;
+
+    private LeakedConnectionException() {
+      super("Connection was opened at " + Instant.now());
+    }
+  }
+
+  private volatile LeakedConnectionException leakedException = new LeakedConnectionException();
+  private final SpannerPool spannerPool;
+  private final StatementParser parser = StatementParser.INSTANCE;
+  /**
+   * The {@link ConnectionStatementExecutor} is responsible for translating parsed {@link
+   * ClientSideStatement}s into actual method calls on this {@link ConnectionImpl}. I.e. the {@link
+   * ClientSideStatement} 'SET AUTOCOMMIT ON' will be translated into the method call {@link
+   * ConnectionImpl#setAutocommit(boolean)} with value <code>true</code>.
+   */
+  private final ConnectionStatementExecutor connectionStatementExecutor =
+      new ConnectionStatementExecutorImpl(this);
+
+}

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AbstractMultiUseTransaction.java

@@ -16,6 +16,7 @@
 
 package com.google.cloud.spanner.connection;
 
+import com.google.cloud.spanner.AsyncResultSet;
 import com.google.cloud.spanner.ErrorCode;
 import com.google.cloud.spanner.Options.QueryOption;
 import com.google.cloud.spanner.ReadContext;
@@ -73,6 +74,16 @@ public ResultSet call() throws Exception {
         });
   }
 
+  @Override
+  public AsyncResultSet executeQueryAsync(
+      final ParsedStatement statement,
+      final AnalyzeMode analyzeMode,
+      final QueryOption... options) {
+    Preconditions.checkArgument(statement.isQuery(), "Statement is not a query");
+    checkValidTransaction();
+    return getReadContext().executeQueryAsync(statement.getStatement(), options);
+  }
+
   ResultSet internalExecuteQuery(
       final ParsedStatement statement, AnalyzeMode analyzeMode, QueryOption... options) {
     if (analyzeMode == AnalyzeMode.NONE) {

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AsyncChecksumResultSet.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.cloud.spanner.connection;
+
+import com.google.api.core.ApiFuture;
+import com.google.cloud.spanner.AsyncResultSet;
+import com.google.cloud.spanner.Options.QueryOption;
+import com.google.cloud.spanner.SpannerException;
+import com.google.cloud.spanner.StructReader;
+import com.google.cloud.spanner.connection.StatementParser.ParsedStatement;
+import com.google.common.base.Function;
+import com.google.common.collect.ImmutableList;
+import java.util.concurrent.Executor;
+
+class AsyncChecksumResultSet extends ChecksumResultSet implements AsyncResultSet {
+  private AsyncResultSet delegate;
+
+  AsyncChecksumResultSet(
+      ReadWriteTransaction transaction,
+      AsyncResultSet delegate,
+      ParsedStatement statement,
+      AnalyzeMode analyzeMode,
+      QueryOption... options) {
+    super(transaction, delegate, statement, analyzeMode, options);
+    this.delegate = delegate;
+  }
+
+  @Override
+  public CursorState tryNext() throws SpannerException {
+    return delegate.tryNext();
+  }
+
+  @Override
+  public ApiFuture<Void> setCallback(Executor exec, ReadyCallback cb) {
+    return delegate.setCallback(exec, cb);
+  }
+
+  @Override
+  public void cancel() {
+    delegate.cancel();
+  }
+
+  @Override
+  public void resume() {
+    delegate.resume();
+  }
+
+  @Override
+  public <T> ApiFuture<ImmutableList<T>> toListAsync(
+      Function<StructReader, T> transformer, Executor executor) {
+    return delegate.toListAsync(transformer, executor);
+  }
+
+  @Override
+  public <T> ImmutableList<T> toList(Function<StructReader, T> transformer)
+      throws SpannerException {
+    return delegate.toList(transformer);
+  }
+}