text: <?php
  /*
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * This software consists of voluntary contributions made by many individuals
   * and is licensed under the MIT license. For more information, see
   * <http://www.doctrine-project.org>.
   */
  
  namespace Doctrine\DBAL\Schema\Visitor;
  
  use Doctrine\DBAL\Platforms\AbstractPlatform;
  use Doctrine\DBAL\Schema\Table;
  use Doctrine\DBAL\Schema\ForeignKeyConstraint;
  use Doctrine\DBAL\Schema\Sequence;
  use Doctrine\DBAL\Schema\SchemaException;
  
  /**
   * Gathers SQL statements that allow to completely drop the current schema.
   *
   * @link   www.doctrine-project.org
   * @since  2.0
   * @author Benjamin Eberlei <kontakt@beberlei.de>
   */
  class DropSchemaSqlCollector extends AbstractVisitor
  {
      /**
       * @var \SplObjectStorage
       */
      private $constraints;
  
      /**
       * @var \SplObjectStorage
       */
      private $sequences;
  
      /**
       * @var \SplObjectStorage
       */
      private $tables;
  
      /**
       * @var \Doctrine\DBAL\Platforms\AbstractPlatform
       */
      private $platform;
  
      /**
       * @param \Doctrine\DBAL\Platforms\AbstractPlatform $platform
       */
      public function __construct(AbstractPlatform $platform)
      {
          $this->platform = $platform;
          $this->clearQueries();
      }
  
      /**
       * {@inheritdoc}
       */
      public function acceptTable(Table $table)
      {
          $this->tables->attach($table);
      }
  
      /**
       * {@inheritdoc}
       */
      public function acceptForeignKey(Table $localTable, ForeignKeyConstraint $fkConstraint)
      {
          if (strlen($fkConstraint->getName()) == 0) {
              throw SchemaException::namedForeignKeyRequired($localTable, $fkConstraint);
          }
  
          $this->constraints->attach($fkConstraint);
          $this->constraints[$fkConstraint] = $localTable;
      }
  
      /**
       * {@inheritdoc}
       */
      public function acceptSequence(Sequence $sequence)
      {
          $this->sequences->attach($sequence);
      }
  
      /**
       * @return void
       */
      public function clearQueries()
      {
          $this->constraints = new \SplObjectStorage();
          $this->sequences = new \SplObjectStorage();
          $this->tables = new \SplObjectStorage();
      }
  
      /**
       * @return array
       */
      public function getQueries()
      {
          $sql = array();
  
          foreach ($this->constraints as $fkConstraint) {
              $localTable = $this->constraints[$fkConstraint];
              $sql[] = $this->platform->getDropForeignKeySQL($fkConstraint, $localTable);
          }
  
          foreach ($this->sequences as $sequence) {
              $sql[] = $this->platform->getDropSequenceSQL($sequence);
          }
  
          foreach ($this->tables as $table) {
              $sql[] = $this->platform->getDropTableSQL($table);
          }
  
          return $sql;
      }
  }
  