# DerbyDatabaseSettings.java

    package org.codefilarete.stalactite.sql;

    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.SQLException;
    import java.util.Collections;
    import java.util.stream.LongStream;

    import org.apache.derby.impl.jdbc.EmbedConnection;
    import org.apache.derby.impl.jdbc.EmbedStatement;
    import org.codefilarete.stalactite.engine.DatabaseVendorSettings;
    import org.codefilarete.stalactite.engine.SQLOperationsFactories;
    import org.codefilarete.stalactite.engine.SQLOperationsFactoriesBuilder;
    import org.codefilarete.stalactite.mapping.id.sequence.DatabaseSequenceSelector;
    import org.codefilarete.stalactite.sql.DerbyDialectResolver.DerbyDatabaseSignet;
    import org.codefilarete.stalactite.sql.ddl.DDLSequenceGenerator;
    import org.codefilarete.stalactite.sql.ddl.DerbyDDLTableGenerator;
    import org.codefilarete.stalactite.sql.ddl.SqlTypeRegistry;
    import org.codefilarete.stalactite.sql.ddl.structure.Column;
    import org.codefilarete.stalactite.sql.statement.DMLGenerator;
    import org.codefilarete.stalactite.sql.statement.DerbyReadOperation;
    import org.codefilarete.stalactite.sql.statement.GeneratedKeysReader;
    import org.codefilarete.stalactite.sql.statement.ReadOperation;
    import org.codefilarete.stalactite.sql.statement.ReadOperationFactory;
    import org.codefilarete.stalactite.sql.statement.SQLStatement;
    import org.codefilarete.stalactite.sql.statement.WriteOperation;
    import org.codefilarete.stalactite.sql.statement.WriteOperation.RowCountListener;
    import org.codefilarete.stalactite.sql.statement.WriteOperationFactory;
    import org.codefilarete.stalactite.sql.statement.binder.DerbyParameterBinderRegistry;
    import org.codefilarete.stalactite.sql.statement.binder.DerbyTypeMapping;
    import org.codefilarete.stalactite.sql.statement.binder.ParameterBinder;
    import org.codefilarete.stalactite.sql.statement.binder.ParameterBinderIndex;
    import org.codefilarete.tool.VisibleForTesting;
    import org.codefilarete.tool.collection.CaseInsensitiveSet;
    import org.codefilarete.tool.function.ThrowingBiFunction;

    import static org.codefilarete.tool.bean.Objects.preventNull;

    /**
     *
     * @author Guillaume Mary
     */
    public class DerbyDatabaseSettings extends DatabaseVendorSettings {

    	/**
    	 * Derby keywords, took from <a href="https://db.apache.org/derby/docs/10.14/ref/rrefkeywords29722.html">Derby documentation</a> because those of
    	 * it JDBC Drivers are not enough / accurate (see {@link org.apache.derby.impl.jdbc.EmbedDatabaseMetaData#getSQLKeywords()})
    	 */
    	@VisibleForTesting
    	static final String[] KEYWORDS = new String[] {
    			"ADD", "ALL", "ALLOCATE", "ALTER", "AND", "ANY", "ARE", "AS", "ASC", "ASSERTION", "AT", "AUTHORIZATION", "AVG",
    			"BEGIN", "BETWEEN", "BIGINT", "BIT", "BOOLEAN", "BOTH", "BY",
    			"CALL", "CASCADE", "CASCADED", "CASE", "CAST", "CHAR", "CHARACTER", "CHARACTER_LENGTH", "CHECK", "CLOSE", "COALESCE", "COLLATE", "COLLATION", "COLUMN",
    				"COMMIT", "CONNECT", "CONNECTION", "CONSTRAINT", "CONSTRAINTS", "CONTINUE", "CONVERT", "CORRESPONDING", "CREATE", "CROSS", "CURRENT",
    				"CURRENT_DATE", "CURRENT_ROLE", "CURRENT_TIME", "CURRENT_TIMESTAMP", "CURRENT_USER", "CURSOR",
    			"DEALLOCATE", "DEC", "DECIMAL", "DECLARE", "DEFAULT", "DEFERRABLE", "DEFERRED", "DELETE", "DESC", "DESCRIBE", "DIAGNOSTICS", "DISCONNECT", "DISTINCT", "DOUBLE", "DROP",
    			"ELSE", "END", "END-EXEC", "ESCAPE", "EXCEPT", "EXCEPTION", "EXEC", "EXECUTE", "EXISTS", "EXPLAIN", "EXTERNAL",
    			"FALSE", "FETCH", "FIRST", "FLOAT", "FOR", "FOREIGN", "FOUND", "FROM", "FULL", "FUNCTION",
    			"GET", "GETCURRENTCONNECTION", "GLOBAL", "GO", "GOTO", "GRANT", "GROUP",
    			"HAVING", "HOUR",
    			"IDENTITY", "IMMEDIATE", "IN", "INDICATOR", "INITIALLY", "INNER", "INOUT", "INPUT", "INSENSITIVE", "INSERT", "INT", "INTEGER", "INTERSECT", "INTO", "IS", "ISOLATION",
    			"JOIN",
    			"KEY",
    			"LAST", "LEADING", "LEFT", "LIKE", "LOWER", "LTRIM",
    			"MATCH", "MAX", "MIN", "MINUTE",
    			"NATIONAL", "NATURAL", "NCHAR", "NVARCHAR", "NEXT", "NO", "NONE", "NOT", "NULL", "NULLIF", "NUMERIC",
    			"OF", "ON", "ONLY", "OPEN", "OPTION", "OR", "ORDER", "OUTER", "OUTPUT", "OVERLAPS",
    			"PAD", "PARTIAL", "PREPARE", "PRESERVE", "PRIMARY", "PRIOR", "PRIVILEGES", "PROCEDURE", "PUBLIC",
    			"READ", "REAL", "REFERENCES", "RELATIVE", "RESTRICT", "REVOKE", "RIGHT", "ROLLBACK", "ROWS", "RTRIM",
    			"SCHEMA", "SCROLL", "SECOND", "SELECT", "SESSION_USER", "SET", "SMALLINT", "SOME", "SPACE", "SQL", "SQLCODE", "SQLERROR", "SQLSTATE", "SUBSTR", "SUBSTRING", "SUM", "SYSTEM_USER",
    			"TABLE", "TEMPORARY", "TIMEZONE_HOUR", "TIMEZONE_MINUTE", "TO", "TRANSACTION", "TRANSLATE", "TRANSLATION", "TRIM", "TRUE",
    			"UNION", "UNIQUE", "UNKNOWN", "UPDATE", "UPPER", "USER", "USING",
    			"VALUES", "VARCHAR", "VARYING", "VIEW",
    			"WHENEVER", "WHERE", "WINDOW", "WITH", "WORK", "WRITE",
    			"XML", "XMLEXISTS", "XMLPARSE", "XMLQUERY", "XMLSERIALIZE",
    			"YEAR"
    	};

    	// Technical note: DO NOT declare settings BEFORE KEYWORDS field because it requires it and the JVM makes KEYWORDS null at this early stage (strange)
    	public static final DerbyDatabaseSettings DERBY_10_14 = new DerbyDatabaseSettings();

    	private DerbyDatabaseSettings() {
    		this(new DerbySQLOperationsFactoriesBuilder(), new DerbyParameterBinderRegistry());
    	}

    	private DerbyDatabaseSettings(DerbySQLOperationsFactoriesBuilder sqlOperationsFactoriesBuilder, DerbyParameterBinderRegistry parameterBinderRegistry) {
    		super(new DerbyDatabaseSignet(10, 14),
    				Collections.unmodifiableSet(new CaseInsensitiveSet(KEYWORDS)),
    				'"',
    				new DerbyTypeMapping(),
    				parameterBinderRegistry,
    				sqlOperationsFactoriesBuilder,
    				new DerbyGeneratedKeysReaderFactory(),
    				1000,
    				true);
    	}

    	private static class DerbySQLOperationsFactoriesBuilder implements SQLOperationsFactoriesBuilder {

    		private final DerbyReadOperationFactory readOperationFactory;
    		private final DerbyWriteOperationFactory writeOperationFactory;

    		private DerbySQLOperationsFactoriesBuilder() {
    			this.readOperationFactory = new DerbyReadOperationFactory();
    			this.writeOperationFactory = new DerbyWriteOperationFactory();
    		}

    		private DerbyReadOperationFactory getReadOperationFactory() {
    			return readOperationFactory;
    		}

    		private DerbyWriteOperationFactory getWriteOperationFactory() {
    			return writeOperationFactory;
    		}

    		@Override
    		public SQLOperationsFactories build(ParameterBinderIndex<Column, ParameterBinder> parameterBinders, DMLNameProviderFactory dmlNameProviderFactory, SqlTypeRegistry sqlTypeRegistry) {
    			DMLGenerator dmlGenerator = new DMLGenerator(parameterBinders, DMLGenerator.NoopSorter.INSTANCE, dmlNameProviderFactory);
    			DerbyDDLTableGenerator ddlTableGenerator = new DerbyDDLTableGenerator(sqlTypeRegistry, dmlNameProviderFactory);
    			DDLSequenceGenerator ddlSequenceGenerator = new DDLSequenceGenerator(dmlNameProviderFactory);
    			return new SQLOperationsFactories(writeOperationFactory, readOperationFactory, dmlGenerator, ddlTableGenerator, ddlSequenceGenerator, new DerbySequenceSelectorFactory(readOperationFactory));
    		}
    	}

    	public static class DerbyReadOperationFactory extends ReadOperationFactory {

    		public DerbyReadOperationFactory() {
    			this(null);
    		}

    		public DerbyReadOperationFactory(Integer fetchSize) {
    			super(fetchSize);
    		}

    		@Override
    		public <ParamType> ReadOperation<ParamType> createInstance(SQLStatement<ParamType> sqlGenerator, ConnectionProvider connectionProvider, Integer fetchSize) {
    			return new DerbyReadOperation<>(sqlGenerator, connectionProvider, preventNull(fetchSize, super.fetchSize));
    		}
    	}

    	public static class DerbyWriteOperationFactory extends WriteOperationFactory {

    		@Override
    		protected <ParamType> WriteOperation<ParamType> createInstance(SQLStatement<ParamType> sqlGenerator,
    																	   ConnectionProvider connectionProvider,
    																	   ThrowingBiFunction<Connection, String, PreparedStatement, SQLException> statementProvider,
    																	   RowCountListener rowCountListener) {
    			return new DerbyWriteOperation<ParamType>(sqlGenerator, connectionProvider, rowCountListener) {
    				@Override
    				protected void prepareStatement(Connection connection) throws SQLException {
    					this.preparedStatement = statementProvider.apply(connection, getSQL());
    				}
    			};
    		}
    	}

    	/**
    	 * Made package-private to be visible by {@link DerbyGeneratedKeysReader}
    	 * @param <ParamType>
    	 */
    	static class DerbyWriteOperation<ParamType> extends WriteOperation<ParamType> {

    		/** Updated row count of the last executed batch statement */
    		private long updatedRowCount = 0;

    		public DerbyWriteOperation(SQLStatement<ParamType> sqlGenerator, ConnectionProvider connectionProvider, RowCountListener rowCountListener) {
    			super(sqlGenerator, connectionProvider, rowCountListener);
    		}

    		public long getUpdatedRowCount() {
    			return updatedRowCount;
    		}

    		protected long[] doExecuteBatch() throws SQLException {
    			long[] rowCounts = super.doExecuteBatch();
    			this.updatedRowCount = LongStream.of(rowCounts).sum();
    			return rowCounts;
    		}

    		/**
    		 * Overridden to use Derby special {@link EmbedConnection#cancelRunningStatement()} method
    		 * to avoid exception "ERROR 0A000: Feature not implemented: cancel" (see {@link EmbedStatement#cancel()} implementation).
    		 *
    		 * @throws SQLException if cancellation fails
    		 */
    		@Override
    		public void cancel() throws SQLException {
    			EmbedConnection conn = preparedStatement.getConnection().unwrap(EmbedConnection.class);
    			conn.cancelRunningStatement();
    		}
    	}

    	private static class DerbySequenceSelectorFactory implements DatabaseSequenceSelectorFactory {

    		private final ReadOperationFactory readOperationFactory;

    		private DerbySequenceSelectorFactory(ReadOperationFactory readOperationFactory) {
    			this.readOperationFactory = readOperationFactory;
    		}

    		@Override
    		public DatabaseSequenceSelector create(org.codefilarete.stalactite.sql.ddl.structure.Sequence databaseSequence, ConnectionProvider connectionProvider) {
    			return new DatabaseSequenceSelector(databaseSequence, "values next value for " + databaseSequence.getAbsoluteName(), readOperationFactory, connectionProvider);
    		}
    	}

    	@VisibleForTesting
    	static class DerbyGeneratedKeysReaderFactory implements GeneratedKeysReaderFactory {
    		@Override
    		public <I> GeneratedKeysReader<I> build(String keyName, Class<I> columnType) {
    			return (GeneratedKeysReader<I>) new DerbyGeneratedKeysReader();
    		}
    	}
    }