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Class sqlj.runtime.ExecutionContext
java.lang.Object
|
+----sqlj.runtime.ExecutionContext
- public class ExecutionContext
- extends Object
An execution context provides the context in which executable sql
operations are preformed. An execution context object contains a number
of operations for execution control, execution status, and execution
cancellation. Execution control operations modify the semantics of
subsequent sql operations executed on this context. Execution status
operations describe the results of the last sql operation executed on
this context. Execution cancellation methods terminate the currently
executing sql operation on this context.
Note that concurrently executing sql operations are expected to use
distinct execution contexts. The execution context implementation is
not expected to support multiple sql operations executing using the same
execution context object. The client is responsible
for insuring the proper creation of distinct execution context instance
where needed, or synchronizing the execution of operations on a
particular execution context.
- See Also:
- getExecutionContext
-
EXCEPTION_COUNT
- Constant returned by getUpdateCount indicating that an exeception
was thrown before the last execution was successfully completed,
or no operation has yet been attempted on this context.
-
QUERY_COUNT
- Constant returned by getUpdateCount indicating that the last execution
produced a result set or iterator.
-
ExecutionContext()
-
-
cancel()
- The cancel method can be used by one thread to cancel a sql operation
that is currently being executed by another thread using this context.
-
execute()
- Performs a generic execute on the currently registered
statement.
-
executeQuery()
- Performs an execute query on the currently registered statement.
-
executeUpdate()
- Performs an execute update on the currently registered statement.
-
getMaxFieldSize()
-
The max field size limit (in bytes) is the maximum amount of data
returned for any column value for sql operations subsequently executed
using this context; it only applies to BINARY, VARBINARY,
LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR columns.
-
getMaxRows()
- The max rows limit is the maximum number of rows that any
ResultSetIterator or jdbc ResultSet returned by sql operations
subsequently executed using this context can contain.
-
getNextResultSet()
-
Moves to the currently registered statement's next result.
-
getQueryTimeout()
- The query timeout limit is the maxiumum number of seconds sql opeations
subsequently executed using this context may take to complete.
-
getUpdateCount()
- Returns the number of rows updated by the last sql operation executed
using this context.
-
getWarnings()
-
Returns the first warning reported by the last sql operation executed
using this context.
-
registerStatement(ConnectionContext, Object, int)
-
Creates, registers and returns a statement.
-
releaseStatement()
- Releases the currently registered statement, signaling that all
execution-related operations have completed.
-
setMaxFieldSize(int)
- The max field size limit (in bytes) is the maximum amount of data
returned for any column value for sql operations subsequently executed
using this context; it only applies to BINARY, VARBINARY,
LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR columns.
-
setMaxRows(int)
- The max rows limit is the maximum number of rows that any
ResultSetIterator or jdbc ResultSet returned by sql operations
subsequently executed using this context can contain.
-
setQueryTimeout(int)
-
The query timeout limit is the maxiumum number of seconds sql opeations
subsequently executed using this context may take to complete.
QUERY_COUNT
public static final int QUERY_COUNT
- Constant returned by getUpdateCount indicating that the last execution
produced a result set or iterator.
- See Also:
- getUpdateCount
EXCEPTION_COUNT
public static final int EXCEPTION_COUNT
- Constant returned by getUpdateCount indicating that an exeception
was thrown before the last execution was successfully completed,
or no operation has yet been attempted on this context.
- See Also:
- getUpdateCount
ExecutionContext
public ExecutionContext()
getMaxFieldSize
public int getMaxFieldSize()
- The max field size limit (in bytes) is the maximum amount of data
returned for any column value for sql operations subsequently executed
using this context; it only applies to BINARY, VARBINARY,
LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR columns. These columns
may be fetched into Java targets of type byte[], String, or stream.
The limit effects both out and in-out parameters passed, and the
result returned from any executable sql operation. If the limit is
exceeded, the excess data is silently discarded.
By default, the max field size limit is zero (unlimited)
- Returns:
- the current max field size limit; zero means unlimited
setMaxFieldSize
public void setMaxFieldSize(int max)
- The max field size limit (in bytes) is the maximum amount of data
returned for any column value for sql operations subsequently executed
using this context; it only applies to BINARY, VARBINARY,
LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR columns. These columns
may be fetched into Java targets of type byte[], String, or stream.
The limit effects both out and in-out parameters passed, and the
result returned from any executable sql operation. If the limit is
exceeded, the excess data is silently discarded. For maximum
portability use values greater than 256.
By default, the max field size limit is zero (unlimited)
Note: max field size is an optional feature that may not be
supported by some implementations. Setting max field size to a
non-default value may cause an SQLException to be raised when an
SQL operation is executed using this context.
- Parameters:
- max - the new max field size limit; zero means unlimited
getMaxRows
public int getMaxRows()
- The max rows limit is the maximum number of rows that any
ResultSetIterator or jdbc ResultSet returned by sql operations
subsequently executed using this context can contain. If the limit is
exceeded, the excess rows are silently dropped.
By default, the max rows limit is zero (unlimited)
- Returns:
- the current max rows limit; zero means unlimited
setMaxRows
public void setMaxRows(int max)
- The max rows limit is the maximum number of rows that any
ResultSetIterator or jdbc ResultSet returned by sql operations
subsequently executed using this context can contain. If the limit is
exceeded, the excess rows are silently dropped.
By default, the max rows limit is zero (unlimited)
Note: max rows is an optional feature that may not be
supported by some implementations. Setting max rows to a non-default
value may cause an SQLException to be raised when an SQL operation is
executed using this context.
- Parameters:
- max - the new max rows limit; zero means unlimited
getQueryTimeout
public int getQueryTimeout()
- The query timeout limit is the maxiumum number of seconds sql opeations
subsequently executed using this context may take to complete.
If execution of the sql operation exceeds the limit, a SQLException is
thrown.
By default, the query timeout limit is zero (unlimited)
- Returns:
- the current query timeout limit in seconds;
zero means unlimited
setQueryTimeout
public void setQueryTimeout(int seconds)
- The query timeout limit is the maxiumum number of seconds sql opeations
subsequently executed using this context may take to complete.
If execution of the sql operation exceeds the limit, a SQLException is
thrown.
By default, the query timeout limit is zero (unlimited)
Note: query timeout is an optional feature that may not be
supported by some implementations. Setting query timeout to a
non-default value may cause an SQLException to be raised when an
SQL operation is executed using this context.
- Parameters:
- seconds - the new query timeout limit in seconds; zero means
unlimited
getWarnings
public SQLWarning getWarnings()
- Returns the first warning reported by the last sql operation executed
using this context. Subsequent warnings resultant from the same
operation will be chained to this SQLWarning. The SQLWarning chain
returned represents those warnings which occured during the execution
of the last sql operation and the subsequent binding of any output host
variables.
- Returns:
- the first SQLWarning or null if no warnings occurred
getUpdateCount
public int getUpdateCount()
- Returns the number of rows updated by the last sql operation executed
using this context. 0 is returned if the last sql operation was not a
DML statement. QUERY_COUNT is
returned if the last sql operation produced an iterator or result
set. EXCEPTION_COUNT is returned
if an exception occurred before the last sql operation completed
execution, or no operation has yet been attempted.
- Returns:
- the number of rows updated by the last operation
cancel
public void cancel() throws SQLException
- The cancel method can be used by one thread to cancel a sql operation
that is currently being executed by another thread using this context.
Note that this method has no effect if there is no statement currently
being executed for this execution context.
- Throws: SQLException
- if unable to cancel
- See Also:
- executeUpdate, executeQuery
registerStatement
public synchronized RTStatement registerStatement(ConnectionContext connCtx,
Object profileKey,
int stmtNdx) throws SQLException
- Creates, registers and returns a statement. This method is called
by generated code. Most programmers will not need to call it
directly.
The statement is created by accessing the connected profile within
connection context "connCtx" that has the key "profileKey". The
statement at index "stmtNdx" in the connected profile is created using
the getStatement
method.
The statement created is registered and becomes the current
statement of this execution context. All warnings are cleared, and
updateCount is initialized to
EXCEPTION_COUNT.
For each of the max rows, max field size, and query timeout
attributes of this execution context, if the attribute has a
non-default value, then the corresponding attribute of the registered
statement is set to this value. An exception is raised if the
statement does not support setting the attribute. The attributes of
the execution context contained by the passed connection context are
not used by this method.
If there is another statement currently executing on this execution
context, an exception is raised. Note that if this method throws an
exception, no statement will be registered.
- Parameters:
- connCtx - the connection context that contains the profile that
contains the statement to register.
- profileKey - the key of the connected profile within the
connection context.
- stmtNdx - the 0-based index of the statement within the profile
to be registered.
- Throws: SQLException
- if there is another statement currently executing or the max fields
size, max rows, or query timeout cannot be set on the registered
statement.
- See Also:
- releaseStatement, getStatement, getConnectedProfile
executeUpdate
public int executeUpdate() throws SQLException
- Performs an execute update on the currently registered statement.
The update count is updated accordingly.
Note: This method is called by generated code. Most
programmers will not need to call it directly.
- Returns:
- the result of calling executeUpdate on the currently
registered statement
- Throws: SQLException
- if an error occurs during the execution of the
currently registered statement.
- See Also:
- executeUpdate, registerStatement
executeQuery
public RTResultSet executeQuery() throws SQLException
- Performs an execute query on the currently registered statement.
The update count is set to QUERY_COUNT.
Note: This method is called by generated code. Most
programmers will not need to call it directly.
- Returns:
- the result of calling executeRTQuery on the currently
registered statement
- Throws: SQLException
- if an error occurs during the execution of the
currently registered statement.
- See Also:
- executeRTQuery, registerStatement
execute
public boolean execute() throws SQLException
- Performs a generic execute on the currently registered
statement. Under some situations a single SQL CALL statement may
return multiple result sets. The "execute" and "getNextResultSet"
methods allow navigation through multiple results.
The "execute" method executes the currently registered statement
and returns true if it produced a side-channel result set, false
otherwise. The getNextResultSet method is used to obtain the result
set. Update count is set to
QUERY_COUNT.
Notes:
- This method is called by generated code. Most programmers will not
need to call it directly. Instead, they will use only
"getNextResultSet" to navigate multiple results.
- If the current operation produces multiple results, it is not
released until all results have been processed, and getNextResultSet
returns null.
- If this operation also produces side-channel update counts, they
are silently discarded.
- If an error occurs executing the SQL operation, the current
statement is released and an SQLException is raised. Subsequent calls
to "getNextResultSet" will return null.
- Returns:
- true if the statement produced a side-channel result set,
false otherwise.
- Throws: SQLException
- if an error occurs during the execution of the currently registered
statement.
- See Also:
- execute, registerStatement, getNextResultSet
getNextResultSet
public ResultSet getNextResultSet() throws SQLException
- Moves to the currently registered statement's next result. The first
time this method is called after a SQL operation is executed, the
first side-channel result set is returned (if any). Further calls to
getNextResultSet will move to any subsequent results. getNextResultSet
implicitly closes any open result set previously obtained with
getNextResultSet.
getNextResultSet returns null when there are no further results.
null is also returned if the last SQL operation executed did not
produce side-channel results, or an SQL operation has not yet been
executed on this execution context.
Notes:
- If the last SQL operation executed on this execution context
produced multiple results, its resources are not released until all
results have been processed, and getNextResultSet returns null. In
such cases, this execution context cannot be used to execute further
SQL operations until all results have been processed.
- If this operation also produces side-channel update counts, they
are silently discarded.
- If an error occurs during a call to getNextResultSet, the current
statement is released and an SQLException is raised. Subsequent calls
to getNextResultSet will return null.
- Returns:
- the next side-channel result set, or null if there are no
further results.
- Throws: SQLException
- if an error occurs obtaining the next result set.
- See Also:
- getResultSet, getMoreResults, execute, registerStatement
releaseStatement
public synchronized void releaseStatement() throws SQLException
- Releases the currently registered statement, signaling that all
execution-related operations have completed. After this method has
been returned from, it is safe to call registerStatement again. The
SQL warnings are updated as reflected by the registered statement.
This method calls the executeComplete
method of the
registered statement.
If the execution of the currently registered statement produced
multiple results and not all results have been processed, then this
operation is a no-op. In such cases, this method will be
automatically called to release the statement once all results have
been processed and getMoreResults returns NO_MORE_RESULTS.
Note: This method is called by generated code. Most
programmers will not need to call it directly.
- Throws: SQLException
- if an error occurs retrieving the warnings
- See Also:
- registerStatement, executeComplete
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