org.postgresql.core.v2

Class QueryExecutorImpl

java.lang.Object

org.postgresql.core.v2.QueryExecutorImpl

All Implemented Interfaces:

QueryExecutor

public class QueryExecutorImpl
extends Object
implements QueryExecutor

QueryExecutor implementation for the V2 protocol.

Field Summary

Fields inherited from interface org.postgresql.core.QueryExecutor

QUERY_BOTH_ROWS_AND_STATUS, QUERY_DESCRIBE_ONLY, QUERY_DISALLOW_BATCHING, QUERY_FORCE_DESCRIBE_PORTAL, QUERY_FORWARD_CURSOR, QUERY_NO_BINARY_TRANSFER, QUERY_NO_METADATA, QUERY_NO_RESULTS, QUERY_ONESHOT, QUERY_SUPPRESS_BEGIN

Constructor Summary

Constructors

Constructor and Description
QueryExecutorImpl(org.postgresql.core.v2.ProtocolConnectionImpl protoConnection, PGStream pgStream, Logger logger)

Method Summary

Methods

Modifier and Type	Method and Description
ParameterList	createFastpathParameters(int count) Create a new ParameterList implementation suitable for invoking a fastpath function via QueryExecutor.fastpathCall(int, org.postgresql.core.ParameterList, boolean).
Query	createParameterizedQuery(String sql) Create a parameterized Query object suitable for execution by this QueryExecutor.
Query	createSimpleQuery(String sql) Create an unparameterized Query object suitable for execution by this QueryExecutor.
void	execute(Query[] queries, ParameterList[] parameters, ResultHandler handler, int maxRows, int fetchSize, int flags) Execute several Query, passing results to a provided ResultHandler.
void	execute(Query query, ParameterList parameters, ResultHandler handler, int maxRows, int fetchSize, int flags) Execute a Query, passing results to a provided ResultHandler.
byte[]	fastpathCall(int fnid, ParameterList parameters, boolean suppressBegin) Invoke a backend function via the fastpath interface.
void	fetch(ResultCursor cursor, ResultHandler handler, int rows) Fetch additional rows from a cursor.
void	processNotifies() Prior to attempting to retrieve notifications, we need to pull any recently received notifications off of the network buffers.
protected void	processResults(Query originalQuery, ResultHandler handler, int maxRows, int flags)
protected void	sendQuery(org.postgresql.core.v2.V2Query query, org.postgresql.core.v2.SimpleParameterList params, String queryPrefix)
CopyOperation	startCopy(String sql, boolean suppressBegin) Issues a COPY FROM STDIN / COPY TO STDOUT statement and returns handler for associated operation.

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryExecutorImpl

public QueryExecutorImpl(org.postgresql.core.v2.ProtocolConnectionImpl protoConnection,
                 PGStream pgStream,
                 Logger logger)

Method Detail

createSimpleQuery

public Query createSimpleQuery(String sql)

Description copied from interface: QueryExecutor

Create an unparameterized Query object suitable for execution by this QueryExecutor. The provided query string is not parsed for parameter placeholders ('?' characters), and the Query.createParameterList() of the returned object will always return an empty ParameterList.

Specified by:

createSimpleQuery in interface QueryExecutor

Parameters:

sql - the SQL for the query to create

Returns:

a new Query object

createParameterizedQuery

public Query createParameterizedQuery(String sql)

Description copied from interface: QueryExecutor

Create a parameterized Query object suitable for execution by this QueryExecutor. The provided query string is parsed for parameter placeholders ('?' characters), and the Query.createParameterList() of the returned object will create an appropriately-sized ParameterList.

Specified by:

createParameterizedQuery in interface QueryExecutor

Parameters:

sql - the SQL for the query to create, with '?' placeholders for parameters.

Returns:

a new Query object

createFastpathParameters

public ParameterList createFastpathParameters(int count)

Description copied from interface: QueryExecutor

Create a new ParameterList implementation suitable for invoking a fastpath function via QueryExecutor.fastpathCall(int, org.postgresql.core.ParameterList, boolean).

Specified by:

createFastpathParameters in interface QueryExecutor

Parameters:

count - the number of parameters the fastpath call will take

Returns:

a ParameterList suitable for passing to QueryExecutor.fastpathCall(int, org.postgresql.core.ParameterList, boolean).

fastpathCall

public byte[] fastpathCall(int fnid,
                  ParameterList parameters,
                  boolean suppressBegin)
                    throws SQLException

Description copied from interface: QueryExecutor

Invoke a backend function via the fastpath interface.

Specified by:

fastpathCall in interface QueryExecutor

Parameters:

fnid - the OID of the backend function to invoke

parameters - a ParameterList returned from QueryExecutor.createFastpathParameters(int) containing the parameters to pass to the backend function

suppressBegin - if begin should be suppressed

Returns:

the binary-format result of the fastpath call, or null if a void result was returned

Throws:

SQLException - if an error occurs while executing the fastpath call

processNotifies

public void processNotifies()
                     throws SQLException

Description copied from interface: QueryExecutor

Prior to attempting to retrieve notifications, we need to pull any recently received notifications off of the network buffers. The notification retrieval in ProtocolConnection cannot do this as it is prone to deadlock, so the higher level caller must be responsible which requires exposing this method.

Specified by:

processNotifies in interface QueryExecutor

Throws:

SQLException - if and error occurs while fetching notifications

execute

public void execute(Query query,
           ParameterList parameters,
           ResultHandler handler,
           int maxRows,
           int fetchSize,
           int flags)
             throws SQLException

Description copied from interface: QueryExecutor

Execute a Query, passing results to a provided ResultHandler.

Specified by:

execute in interface QueryExecutor

Parameters:

query - the query to execute; must be a query returned from calling QueryExecutor.createSimpleQuery(String) or QueryExecutor.createParameterizedQuery(String) on this QueryExecutor object.

parameters - the parameters for the query. Must be non-null if the query takes parameters. Must be a parameter object returned by Query.createParameterList().

handler - a ResultHandler responsible for handling results generated by this query

maxRows - the maximum number of rows to retrieve

fetchSize - if QUERY_FORWARD_CURSOR is set, the preferred number of rows to retrieve before suspending

flags - a combination of QUERY_* flags indicating how to handle the query.

Throws:

SQLException - if query execution fails

execute

public void execute(Query[] queries,
           ParameterList[] parameters,
           ResultHandler handler,
           int maxRows,
           int fetchSize,
           int flags)
             throws SQLException

Description copied from interface: QueryExecutor

Execute several Query, passing results to a provided ResultHandler.

Specified by:

execute in interface QueryExecutor

Parameters:

queries - the queries to execute; each must be a query returned from calling QueryExecutor.createSimpleQuery(String) or QueryExecutor.createParameterizedQuery(String) on this QueryExecutor object.

parameters - the parameter lists for the queries. The parameter lists correspond 1:1 to the queries passed in the queries array. Each must be non-null if the corresponding query takes parameters, and must be a parameter object returned by Query.createParameterList() created by the corresponding query.

handler - a ResultHandler responsible for handling results generated by this query

maxRows - the maximum number of rows to retrieve

fetchSize - if QUERY_FORWARD_CURSOR is set, the preferred number of rows to retrieve before suspending

flags - a combination of QUERY_* flags indicating how to handle the query.

Throws:

SQLException - if query execution fails

fetch

public void fetch(ResultCursor cursor,
         ResultHandler handler,
         int rows)
           throws SQLException

Description copied from interface: QueryExecutor

Fetch additional rows from a cursor.

Specified by:

fetch in interface QueryExecutor

Parameters:

cursor - the cursor to fetch from

handler - the handler to feed results to

rows - the preferred number of rows to retrieve before suspending

Throws:

SQLException - if query execution fails

sendQuery

protected void sendQuery(org.postgresql.core.v2.V2Query query,
             org.postgresql.core.v2.SimpleParameterList params,
             String queryPrefix)
                  throws IOException

Throws:

IOException

processResults

protected void processResults(Query originalQuery,
                  ResultHandler handler,
                  int maxRows,
                  int flags)
                       throws IOException

Throws:

IOException

startCopy

public CopyOperation startCopy(String sql,
                      boolean suppressBegin)
                        throws SQLException

Description copied from interface: QueryExecutor

Issues a COPY FROM STDIN / COPY TO STDOUT statement and returns handler for associated operation. Until the copy operation completes, no other database operation may be performed. Implemented for protocol version 3 only.

Specified by:

startCopy in interface QueryExecutor

Parameters:

sql - input sql

suppressBegin - if begin should be suppressed

Returns:

handler for associated operation

Throws:

SQLException - when initializing the given query fails