Package org.javalite.activejdbc

Class Base

  • public class Base
extends Object
    This class provides a number of convenience methods for opening/closing database connections, running various types of queries, and executing SQL statements. This class differs from DB such that in this class you a logical name for a connection is hard-coded to be "default". Use this class when you have only one database.

    This class is a convenience wrapper of DB
    Author:
    Igor Polevoy, Eric Nielsen

    • Method Detail

      • open

        public static DB open()
        This method will open a connection defined in the file 'database.properties' set by an initial previous call to DBConfiguration.loadConfiguration(String). The connection picked up from the file is defined by ACTIVE_ENV environment variable or active_env system property. If this variable is not defined, it defaults to 'development' environment. If there is JUnit on classpath, this method assumes it is running under test, and defaults to 'test'.

      • open

        public static DB open​(String driver,
                      String url,
                      String user,
                      String password)
        Opens a new connection based on JDBC properties and attaches it to a current thread.
        Parameters:
        driver - class name of driver
        url - URL connection to DB
        user - user name.
        password - password.

      • open

        public static DB open​(String driver,
                      String url,
                      Properties props)
        Opens a new connection in case additional driver-specific parameters need to be passed in.
        Parameters:
        driver - driver class name
        url - JDBC URL
        props - connection properties

      • open

        public static DB open​(String jndiName)
        Opens a connection from JNDI based on a registered name. This assumes that there is a jndi.properties file with proper JNDI configuration in it.
        Parameters:
        jndiName - name of a configured data source.

      • open

        public static DB open​(String jndiName,
                      Properties jndiProperties)
        Opens a new connection from JNDI data source by name using explicit JNDI properties. This method can be used in cases when file jndi.properties cannot be easily modified.
        Parameters:
        jndiName - name of JNDI data source.
        jndiProperties - JNDI properties

      • open

        public static DB open​(DataSource dataSource)
        Opens a connection from a datasource. This methods gives a high level control while sourcing a DB connection.
        Parameters:
        dataSource - datasource will be used to acquire a connection.

      • connection

        public static Connection connection()
        Returns connection attached to a current thread and named "default".
        Returns:
        connection attached to a current thread and named "default".

      • hasConnection

        public static boolean hasConnection()
        Use to check if there is a default connection present on current thread.
        Returns:
        true if finds default connection on current thread, false if not.

      • close

        public static void close​(boolean suppressWarning)
        Closes connection and detaches it from current thread.
        Parameters:
        suppressWarning - true to not display a warning in case of a problem (connection not there)

      • close

        public static void close()
        Closes connection and detaches it from current thread.

      • count

        public static Long count​(String table)
        Returns count of rows in table.
        Parameters:
        table - name of table.
        Returns:
        count of rows in table.

      • count

        public static Long count​(String table,
                         String query,
                         Object... params)
        Runs a count query, returns a number of matching records.
        Parameters:
        table - table in which to count rows.
        query - this is a filtering query for the count. If '*' provided, all records will be counted. Example: "age > 65 AND department = 'accounting'"
        params - parameters for placeholder substitution.
        Returns:
        copunt number of records found in a table.

      • firstCell

        public static Object firstCell​(String query,
                               Object... params)
        Returns a value of the first column of the first row. This query expects only one column selected in the select statement. If more than one column returned, it will throw IllegalArgumentException.
        Parameters:
        query - query
        params - parameters
        Returns:
        fetched value, or null if query did not fetch anything.

      • findAll

        public static List<Map> findAll​(String query,
                                Object... params)
        This method returns entire resultset as one list. Do not use it for large result sets. Example: 
         List<Map> people = Base.findAll("select * from people where first_name = ?", "John");
 for (Map person : people)
     System.out.println(person.get("first_name"));
        Parameters:
        query - raw SQL query. This query is parametrized.
        params - list of parameters for a parametrized query.
        Returns:
        entire result set corresponding to the query.

      • firstColumn

        public static List firstColumn​(String query,
                               Object... params)
        This method returns entire resultset as one list. Do not use it for large result sets. Example: 
          List ssns = Base.firstColumn("select ssn from people where first_name = ?", "John");
  for(Object ssn: ssns)
      System.out.println(ssn);
        This methods expects a query which selects only one column from a table/view. It will throw an exception if more than one columns are fetched in a result set.
        Parameters:
        query - raw SQL query. This query is parametrized.
        params - list of parameters for a parametrized query.
        Returns:
        entire result set corresponding to the query.

      • findAll

        public static List<Map> findAll​(String query)
        This method returns entire resultset as one list. Do not use it for large result sets.
        Parameters:
        query - raw SQL query. This query is not parametrized.
        Returns:
        entire result set corresponding to the query.

      • find

        public static RowProcessor find​(String query,
                                Object... params)
        Executes a raw query and returns an instance of RowProcessor. Use it in the following pattern: 
         Base.find("select first_name, last_name from really_large_table").with(new RowListenerAdapter() {
            public void onNext(Map row) {
                ///write your code here
                Object o1 = row.get("first_name");
                Object o2 = row.get("last_name");
            }
        });
        Parameters:
        query - raw SQL.
        params - list of parameters if query is parametrized.
        Returns:
        instance of RowProcessor which has with() method for convenience.

      • find

        public static RowProcessor find​(RowProcessor.ResultSetType type,
                                RowProcessor.ResultSetConcur concur,
                                int fetchSize,
                                String query,
                                Object... params)
        Executes a raw query and returns an instance of RowProcessor. Use it in the following pattern: 
           Base.find("select first_name, last_name from really_large_table", ....).with(new RowListenerAdapter() {
     public void onNext(Map row) {
     ///write your code here
     Object o1 = row.get("first_name");
     Object o2 = row.get("last_name");
     }
     });
        See ResultSet Docs
        Parameters:
        query - raw SQL.
        type - type of result set
        concur - concurrent mode of result set
        fetchSize - size of result set
        params - list of parameters if query is parametrized.
        Returns:
        instance of RowProcessor which has with() method for convenience.

      • find

        public static void find​(String sql,
                        RowListener listener)
        Executes a raw query and calls instance of RowListener with every row found. Use this method for very large result sets.
        Parameters:
        sql - raw SQL query.
        listener - client listener implementation for processing individual rows.

      • exec

        public static int exec​(String query)
        Executes DML. Use it for inserts and updates.
        Parameters:
        query - raw DML.
        Returns:
        number of rows afected by query.

      • exec

        public static int exec​(String query,
                       Object... params)
        Executes parametrized DML - will contain question marks as placeholders.
        Parameters:
        query - query to execute - will contain question marks as placeholders.
        params - query parameters.
        Returns:
        number of records affected.

      • openTransaction

        public static void openTransaction()
        Opens local transaction.

      • commitTransaction

        public static void commitTransaction()
        Commits local transaction.

      • rollbackTransaction

        public static void rollbackTransaction()
        Rolls back local transaction.

      • startBatch

        public static PreparedStatement startBatch​(String parametrizedStatement)
        Creates a java.sql.PreparedStatement to be used in batch executions later.
        Parameters:
        parametrizedStatement - Example of a statement: INSERT INTO employees VALUES (?, ?).
        Returns:
        instance of java.sql.PreparedStatement with compiled query.

      • addBatch

        public static void addBatch​(PreparedStatement ps,
                            Object... parameters)
        Adds a batch statement using given java.sql.PreparedStatement and parameters.
        Parameters:
        ps - java.sql.PreparedStatement to add batch to.
        parameters - parameters for the query in java.sql.PreparedStatement. Parameters will be set on the statement in the same order as provided here.

      • executeBatch

        public static int[] executeBatch​(PreparedStatement ps)
        Executes a batch on java.sql.PreparedStatement.
        Parameters:
        ps - java.sql.PreparedStatement to execute batch on.
        Returns:
        an array of update counts containing one element for each command in the batch. The elements of the array are ordered according to the order in which commands were added to the batch.
        See Also:
        Statement#executeBatch()

      • closePreparedStatement

        public static void closePreparedStatement​(PreparedStatement ps)
        Quietly closes the java.sql.PreparedStatement used in a batch execution. The advantage over calling java.sql.PreparedStatement.close() directly is not having to explicitly handle a checked exception (java.sql.SQLException). This method should typically be called in a finally block. So as not to displace any exception (e.g. from a failed batch execution) that might already be in flight, this method swallows any exception that might arise from closing the statement. This is generally seen as a worthwhile trade-off, as it much less likely for a close to fail without a prior failure.
        Parameters:
        ps - java.sql.PreparedStatement with which a batch has been executed. If null, this is a no-op.

      • attach

        public static void attach​(Connection connection)
        Attaches a database connection to current thread under a default name.
        Parameters:
        connection - instance of connection to attach to current thread.

      • detach

        public static Connection detach()
        Detaches a default connection from current thread and returns an instance of it. This method does not close a connection. Use it for cases of advanced connection management, such as integration with Spring Framework.
        Returns:
        instance of a default connection detached from current thread by name passed to constructor.