package liquibase.sqlgenerator.core;

 import liquibase.database.Database;

 import liquibase.database.core.PostgresDatabase;

 import liquibase.exception.LiquibaseException;

 import liquibase.sql.Sql;

 import liquibase.sql.UnparsedSql;

 import liquibase.sqlgenerator.SqlGeneratorChain;

 import liquibase.statement.core.InsertOrUpdateStatement;

 public class InsertOrUpdateGeneratorPostgres extends InsertOrUpdateGenerator {

     @Override

     public boolean supports(InsertOrUpdateStatement statement, Database database) {

         return database instanceof PostgresDatabase;

     }

     @Override

     public Sql[] generateSql(InsertOrUpdateStatement insertOrUpdateStatement, Database database,

             SqlGeneratorChain sqlGeneratorChain) {

         StringBuilder generatedSql = new StringBuilder();

         generatedSql.append("DO\n");

         generatedSql.append("$$\n");

         generatedSql.append("BEGIN\n");

         try {

             generatedSql.append(getUpdateStatement(insertOrUpdateStatement, database,

                     getWhereClause(insertOrUpdateStatement, database), sqlGeneratorChain));

         } catch (LiquibaseException e) {

             // do a select statement instead

             generatedSql.append("select * from "

                     + database.escapeTableName(insertOrUpdateStatement.getSchemaName(),

                             insertOrUpdateStatement.getTableName()) + " WHERE "

                     + getWhereClause(insertOrUpdateStatement, database) + "\n");

         }

         generatedSql.append("IF not found THEN\n");

         generatedSql.append(getInsertStatement(insertOrUpdateStatement, database, sqlGeneratorChain));

         generatedSql.append("END IF;\n");

         generatedSql.append("END;\n");

         generatedSql.append("$$\n");

         generatedSql.append("LANGUAGE plpgsql;\n");

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

     }

     @Override

     protected String getElse(Database arg0) {

         throw new UnsupportedOperationException();

     }

     @Override

     protected String getRecordCheck(InsertOrUpdateStatement arg0, Database arg1, String arg2) {

         throw new UnsupportedOperationException();

     }

 }