package liquibase.sqlgenerator.core;

 import liquibase.database.Database;

 import liquibase.database.core.OracleDatabase;

 import liquibase.exception.ValidationErrors;

 import liquibase.logging.LogFactory;

 import liquibase.sql.Sql;

 import liquibase.sql.UnparsedSql;

 import liquibase.sqlgenerator.SqlGeneratorChain;

 import liquibase.statement.core.DropTableStatement;

 public class DropTableGenerator extends AbstractSqlGenerator<DropTableStatement> {

     @Override

     public ValidationErrors validate(DropTableStatement dropTableStatement, Database database,

             SqlGeneratorChain sqlGeneratorChain) {

         ValidationErrors validationErrors = new ValidationErrors();

         validationErrors.checkRequiredField("tableName", dropTableStatement.getTableName());

         return validationErrors;

     }

     @Override

     public Sql[] generateSql(DropTableStatement statement, Database database, SqlGeneratorChain sqlGeneratorChain) {

         StringBuffer buffer = new StringBuffer();

         buffer.append("DROP TABLE ").append(

                 database.escapeTableName(statement.getSchemaName(), statement.getTableName()));

         if (statement.isCascadeConstraints()) {

             if (database.supportsDropTableCascadeConstraints()) {

                 LogFactory.getLogger().warning("Database does not support drop with cascade");

             } else if (database instanceof OracleDatabase) {

                 buffer.append(" CASCADE CONSTRAINTS");

             } else {

                 buffer.append(" CASCADE");

             }

         }

         return new Sql[] { new UnparsedSql(buffer.toString()) };

     }

 }