content: /*
   * Copyright (c) 2015, 2020, Oracle and/or its affiliates.
   *
   * This program is free software; you can redistribute it and/or modify it under
   * the terms of the GNU General Public License, version 2.0, as published by the
   * Free Software Foundation.
   *
   * This program is also distributed with certain software (including but not
   * limited to OpenSSL) that is licensed under separate terms, as designated in a
   * particular file or component or in included license documentation. The
   * authors of MySQL hereby grant you an additional permission to link the
   * program and your derivative works with the separately licensed software that
   * they have included with MySQL.
   *
   * Without limiting anything contained in the foregoing, this file, which is
   * part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
   * version 1.0, a copy of which can be found at
   * http://oss.oracle.com/licenses/universal-foss-exception.
   *
   * This program is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
   * FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
   * for more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
   */
  
  package com.mysql.cj.xdevapi;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.function.Supplier;
  
  import com.mysql.cj.exceptions.WrongArgumentException;
  import com.mysql.cj.protocol.ResultStreamer;
  
  /**
   * {@link SqlResult} representing a multiple result sets.
   */
  public class SqlMultiResult implements SqlResult, ResultStreamer {
      private Supplier<SqlResult> resultStream;
      private List<SqlResult> pendingResults = new ArrayList<>();
      private SqlResult currentResult;
  
      /**
       * Constructor.
       * 
       * @param resultStream
       *            Supplies the result stream depending on query type. Could be {@link SqlSingleResult}, {@link SqlUpdateResult} etc.
       */
      public SqlMultiResult(Supplier<SqlResult> resultStream) {
          this.resultStream = resultStream;
          this.currentResult = resultStream.get();
      }
  
      private SqlResult getCurrentResult() {
          if (this.currentResult == null) {
              throw new WrongArgumentException("No active result");
          }
          return this.currentResult;
      }
  
      @Override
      public boolean nextResult() {
          if (this.currentResult == null) {
              return false; // there was no first result thus we don't expect other ones
          }
          try {
              if (ResultStreamer.class.isAssignableFrom(this.currentResult.getClass())) {
                  ((ResultStreamer) this.currentResult).finishStreaming();
              }
          } finally {
              // propagate any exception but clear the current result so we don't try to read any more results
              this.currentResult = null;
          }
          this.currentResult = this.pendingResults.size() > 0 ? this.pendingResults.remove(0) : this.resultStream.get();
          return this.currentResult != null;
      }
  
      @Override
      public void finishStreaming() {
          if (this.currentResult == null) {
              return; // there was no first result thus we don't expect other ones
          }
          if (ResultStreamer.class.isAssignableFrom(this.currentResult.getClass())) {
              ((ResultStreamer) this.currentResult).finishStreaming();
          }
          SqlResult pendingRs = null;
          while ((pendingRs = this.resultStream.get()) != null) {
              if (ResultStreamer.class.isAssignableFrom(pendingRs.getClass())) {
                  ((ResultStreamer) pendingRs).finishStreaming();
              }
              this.pendingResults.add(pendingRs);
          }
      }
  
      @Override
      public boolean hasData() {
          return getCurrentResult().hasData();
      }
  
      @Override
      public long getAffectedItemsCount() {
          return getCurrentResult().getAffectedItemsCount();
      }
  
      @Override
      public Long getAutoIncrementValue() {
          return getCurrentResult().getAutoIncrementValue();
      }
  
      @Override
      public int getWarningsCount() {
          return getCurrentResult().getWarningsCount();
      }
  
      @Override
      public Iterator<Warning> getWarnings() {
          return getCurrentResult().getWarnings();
      }
  
      @Override
      public int getColumnCount() {
          return getCurrentResult().getColumnCount();
      }
  
      @Override
      public List<Column> getColumns() {
          return getCurrentResult().getColumns();
      }
  
      @Override
      public List<String> getColumnNames() {
          return getCurrentResult().getColumnNames();
      }
  
      @Override
      public long count() {
          return getCurrentResult().count();
      }
  
      @Override
      public List<Row> fetchAll() {
          return getCurrentResult().fetchAll();
      }
  
      @Override
      public Row next() {
          return getCurrentResult().next();
      }
  
      @Override
      public boolean hasNext() {
          return getCurrentResult().hasNext();
      }
  }
  