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safejdbc
Class SQLExecuter  

java.lang.Object
  safejdbc.SQLExecuter

All Implemented Interfaces:

SQL

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public class SQLExecuter

extends java.lang.Object

implements SQL

This is probably the most important class within the SafeJDBC framework, because this class provides methods to actually access the database.

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Field Summary
private  ConnectionProvider	_conprovider

 

Constructor Summary

SQLExecuter(ConnectionProvider conprovider)           To create an SQLExecuter instance a ConnectionProvider is needed.

 

Method Summary
void	executeTX(TXCodeBlock txCodeBlock)           Use this method, to execute several database calls in a single transaction.
void	query(java.lang.String prepSql, FillingCommand cmd, ResultSetProcessor rsProcessor)           Use this method to execute SQL-Query-Statements such as select from.
void	query(java.lang.String sqlStr, ResultSetProcessor rsProcessor)           Use this method to execute SQL-Query-Statements such as select from. Example:
int	singleIntQuery(java.lang.String sqlStmt)           This method is a convenience method for executing a SQL query which has a single row with a single column containing a number as a result.
int	singleIntQuery(java.lang.String prepSqlStmt, FillingCommand cmd)           This method is a convenience method for executing a SQL query which has a single row with a single column containing a number as a result.
int	update(java.lang.String sqlStr)           Use this method to execute modifying SQL-statements such as insert into or update. Example:
int	update(java.lang.String prepSql, FillingCommand cmd)           Use this method to execute modifying SQL-statements such as insert into or update, with a PreparedStatement.

 

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

 

Field Detail

_conprovider

private ConnectionProvider _conprovider

Constructor Detail

SQLExecuter

public SQLExecuter(ConnectionProvider conprovider)

To create an SQLExecuter instance a ConnectionProvider is needed. Every method that accesses the database, addresses at first the ConnectionProvider to get a connection. So be sure to use a well designed ConnectionProvider implementation. A bad ConnectionProvider implementation is definitely a perfomance penalty for your application.

Method Detail

executeTX

public void executeTX(TXCodeBlock txCodeBlock)
               throws java.sql.SQLException

Use this method, to execute several database calls in a single transaction. If an exception occurs the transaction is rolled back.
Example 1:

 sqlexecuter.executeTX(new TXCodeBlock() {
     public void doTransaction (SQL sql) throws SQLException {
         sql.update ("INSERT INTO customer (id, name) VALUES (1, 'Arno Haase')");
         sql.update ("INSERT INTO customer (id, name) VALUES (2, 'Jan Hermanns')");
     }});
 

Note that the SQL instance passed to doTransaction() can also be handed to methods outside the TXCodeBlock. This is extremly usefull to factor out code.
Example 2:This example does the same as the above.

 private void insertArno(SQL sql) throws SQLException {
     sql.update ("INSERT INTO customer (id, name) VALUES (1, 'Arno Haase')");
 }

 private void insertJan(SQL sql) throws SQLException {
     sql.update ("INSERT INTO customer (id, name) VALUES (2, 'Jan Hermanns')");
 }

 sqlexecuter.executeTX(new TXCodeBlock() {
     public void doTransaction (SQL sql) throws SQLException {
         insertArno(sql);
         insertJan(sql);
     }});
 

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update

public int update(java.lang.String sqlStr)
           throws java.sql.SQLException

Description copied from interface: SQL

Use this method to execute modifying SQL-statements such as insert into or update.
Example:

 sql.update("INSERT INTO customer (id, name) VALUES (1, 'John Smith')");
 

Specified by:

update in interface SQL

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update

public int update(java.lang.String prepSql,
                  FillingCommand cmd)
           throws java.sql.SQLException

Description copied from interface: SQL

Use this method to execute modifying SQL-statements such as insert into or update, with a PreparedStatement. The statement is executed in a separate transaction, the change is committed immediately.
Example:

 final int id = 1;
 final String name = "John Smith";
  
 sql.update("INSERT INTO customer (id, name) VALUES (?, ?)",
            new FillingCommand() {
                public void fill(PreparedStatement s) throws SQLException {
                    s.setInt(1, id);
                    s.setString(2, name);
                }});
 

Specified by:

update in interface SQL

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query

public void query(java.lang.String sqlStr,
                  ResultSetProcessor rsProcessor)
           throws java.sql.SQLException

Description copied from interface: SQL

Use this method to execute SQL-Query-Statements such as select from.
Example:

 sql.query("SELECT id, name FROM customer WHERE id > 0",
           new ResultSetIterator() {
               public void forEachRow(ResultSet rs) throws SQLException {
                   System.out.println(rs.getString("name"));
               }});
 

Specified by:

query in interface SQL

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query

public void query(java.lang.String prepSql,
                  FillingCommand cmd,
                  ResultSetProcessor rsProcessor)
           throws java.sql.SQLException

Description copied from interface: SQL

Use this method to execute SQL-Query-Statements such as select from.
Example:

 final int id_threshold = 3;
      
 sql.query("SELECT id, name FROM customer WHERE id > ?",
           new FillingCommand() {
               public void fill(PreparedStatement s) throws SQLException {
                   s.setInt(1, id_threshold);
               }},
           new ResultSetIterator() {
               public void forEachRow(ResultSet rs) throws SQLException {
                   System.out.println(rs.getString("name"));
               }});
 

Specified by:

query in interface SQL

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singleIntQuery

public int singleIntQuery(java.lang.String sqlStmt)
                   throws java.sql.SQLException

This method is a convenience method for executing a SQL query which has a single row with a single column containing a number as a result. This method is useful for queries such as "SELECT COUNT(*) FROM ... WHERE ...".
If the result set is empty or contains more than one row, an IllegalStateException is thrown.

Specified by:

singleIntQuery in interface SQL

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singleIntQuery

public int singleIntQuery(java.lang.String prepSqlStmt,
                          FillingCommand cmd)
                   throws java.sql.SQLException

This method is a convenience method for executing a SQL query which has a single row with a single column containing a number as a result. This method is useful for queries such as "SELECT COUNT(*) FROM ... WHERE ...".
If the result set is empty or contains more than one row, an IllegalStateException is thrown.

Specified by:

singleIntQuery in interface SQL

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SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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