/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
*/
package org.hibernate.loader.plan.exec.internal;
import java.sql.CallableStatement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.hibernate.HibernateException;
import org.hibernate.LockOptions;
import org.hibernate.ScrollMode;
import org.hibernate.dialect.Dialect;
import org.hibernate.dialect.pagination.LimitHandler;
import org.hibernate.dialect.pagination.LimitHelper;
import org.hibernate.dialect.pagination.NoopLimitHandler;
import org.hibernate.engine.jdbc.ColumnNameCache;
import org.hibernate.engine.jdbc.spi.JdbcServices;
import org.hibernate.engine.jdbc.spi.ResultSetWrapper;
import org.hibernate.engine.spi.PersistenceContext;
import org.hibernate.engine.spi.QueryParameters;
import org.hibernate.engine.spi.RowSelection;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.engine.spi.TypedValue;
import org.hibernate.internal.CoreLogging;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.loader.plan.exec.query.spi.NamedParameterContext;
import org.hibernate.loader.plan.exec.spi.LoadQueryDetails;
import org.hibernate.loader.spi.AfterLoadAction;
import org.hibernate.transform.ResultTransformer;
import org.hibernate.type.Type;
/**
* A superclass for loader implementations based on using LoadPlans.
*
* @see org.hibernate.loader.entity.plan.EntityLoader
* @see org.hibernate.loader.collection.plan.CollectionLoader
* @author Gail Badner
*/
public abstract class AbstractLoadPlanBasedLoader {
private static final CoreMessageLogger log = CoreLogging.messageLogger( AbstractLoadPlanBasedLoader.class );
private final SessionFactoryImplementor factory;
private ColumnNameCache columnNameCache;
/**
* Constructs a {@link AbstractLoadPlanBasedLoader}.
*
* @param factory The session factory
* @see SessionFactoryImplementor
*/
public AbstractLoadPlanBasedLoader(
SessionFactoryImplementor factory) {
this.factory = factory;
}
protected SessionFactoryImplementor getFactory() {
return factory;
}
protected abstract LoadQueryDetails getStaticLoadQuery();
protected abstract int[] getNamedParameterLocs(String name);
protected abstract void autoDiscoverTypes(ResultSet rs);
protected List executeLoad(
SharedSessionContractImplementor session,
QueryParameters queryParameters,
LoadQueryDetails loadQueryDetails,
boolean returnProxies,
ResultTransformer forcedResultTransformer) throws SQLException {
final List<AfterLoadAction> afterLoadActions = new ArrayList<AfterLoadAction>();
return executeLoad(
session,
queryParameters,
loadQueryDetails,
returnProxies,
forcedResultTransformer,
afterLoadActions
);
}
protected List executeLoad(
SharedSessionContractImplementor session,
QueryParameters queryParameters,
LoadQueryDetails loadQueryDetails,
boolean returnProxies,
ResultTransformer forcedResultTransformer,
List<AfterLoadAction> afterLoadActions) throws SQLException {
final PersistenceContext persistenceContext = session.getPersistenceContext();
final boolean defaultReadOnlyOrig = persistenceContext.isDefaultReadOnly();
if ( queryParameters.isReadOnlyInitialized() ) {
// The read-only/modifiable mode for the query was explicitly set.
// Temporarily set the default read-only/modifiable setting to the query's setting.
persistenceContext.setDefaultReadOnly( queryParameters.isReadOnly() );
}
else {
// The read-only/modifiable setting for the query was not initialized.
// Use the default read-only/modifiable from the persistence context instead.
queryParameters.setReadOnly( persistenceContext.isDefaultReadOnly() );
}
persistenceContext.beforeLoad();
try {
List results = null;
final String sql = loadQueryDetails.getSqlStatement();
SqlStatementWrapper wrapper = null;
try {
wrapper = executeQueryStatement( sql, queryParameters, false, afterLoadActions, session );
results = loadQueryDetails.getResultSetProcessor().extractResults(
wrapper.getResultSet(),
session,
queryParameters,
new NamedParameterContext() {
@Override
public int[] getNamedParameterLocations(String name) {
return AbstractLoadPlanBasedLoader.this.getNamedParameterLocs( name );
}
},
returnProxies,
queryParameters.isReadOnly(),
forcedResultTransformer,
afterLoadActions
);
}
finally {
if ( wrapper != null ) {
session.getJdbcCoordinator().getResourceRegistry().release(
wrapper.getResultSet(),
wrapper.getStatement()
);
session.getJdbcCoordinator().getResourceRegistry().release( wrapper.getStatement() );
session.getJdbcCoordinator().afterStatementExecution();
}
persistenceContext.afterLoad();
}
persistenceContext.initializeNonLazyCollections();
return results;
}
finally {
// Restore the original default
persistenceContext.setDefaultReadOnly( defaultReadOnlyOrig );
}
}
protected SqlStatementWrapper executeQueryStatement(
final QueryParameters queryParameters,
final boolean scroll,
List<AfterLoadAction> afterLoadActions,
final SharedSessionContractImplementor session) throws SQLException {
return executeQueryStatement( getStaticLoadQuery().getSqlStatement(), queryParameters, scroll, afterLoadActions, session );
}
protected SqlStatementWrapper executeQueryStatement(
String sqlStatement,
QueryParameters queryParameters,
boolean scroll,
List<AfterLoadAction> afterLoadActions,
SharedSessionContractImplementor session) throws SQLException {
// Processing query filters.
queryParameters.processFilters( sqlStatement, session );
// Applying LIMIT clause.
final LimitHandler limitHandler = getLimitHandler(
queryParameters.getRowSelection()
);
String sql = limitHandler.processSql( queryParameters.getFilteredSQL(), queryParameters.getRowSelection() );
// Adding locks and comments.
sql = preprocessSQL( sql, queryParameters, session.getJdbcServices().getJdbcEnvironment().getDialect(), afterLoadActions );
final PreparedStatement st = prepareQueryStatement( sql, queryParameters, limitHandler, scroll, session );
return new SqlStatementWrapper( st, getResultSet( st, queryParameters.getRowSelection(), limitHandler, queryParameters.hasAutoDiscoverScalarTypes(), session ) );
}
/**
* Build LIMIT clause handler applicable for given selection criteria. Returns {@link org.hibernate.dialect.pagination.NoopLimitHandler} delegate
* if dialect does not support LIMIT expression or processed query does not use pagination.
*
* @param selection Selection criteria.
* @return LIMIT clause delegate.
*/
protected LimitHandler getLimitHandler(RowSelection selection) {
final LimitHandler limitHandler = getFactory().getDialect().getLimitHandler();
return LimitHelper.useLimit( limitHandler, selection ) ? limitHandler : NoopLimitHandler.INSTANCE;
}
private String preprocessSQL(
String sql,
QueryParameters queryParameters,
Dialect dialect,
List<AfterLoadAction> afterLoadActions) {
return getFactory().getSettings().isCommentsEnabled()
? prependComment( sql, queryParameters )
: sql;
}
private String prependComment(String sql, QueryParameters parameters) {
final String comment = parameters.getComment();
if ( comment == null ) {
return sql;
}
else {
return "/* " + comment + " */ " + sql;
}
}
/**
* Obtain a <tt>PreparedStatement</tt> with all parameters pre-bound.
* Bind JDBC-style <tt>?</tt> parameters, named parameters, and
* limit parameters.
*/
protected final PreparedStatement prepareQueryStatement(
final String sql,
final QueryParameters queryParameters,
final LimitHandler limitHandler,
final boolean scroll,
final SharedSessionContractImplementor session) throws SQLException, HibernateException {
final Dialect dialect = session.getJdbcServices().getJdbcEnvironment().getDialect();
final RowSelection selection = queryParameters.getRowSelection();
final boolean useLimit = LimitHelper.useLimit( limitHandler, selection );
final boolean hasFirstRow = LimitHelper.hasFirstRow( selection );
final boolean useLimitOffset = hasFirstRow && useLimit && limitHandler.supportsLimitOffset();
final boolean callable = queryParameters.isCallable();
final ScrollMode scrollMode = getScrollMode( scroll, hasFirstRow, useLimitOffset, queryParameters );
final PreparedStatement st = session.getJdbcCoordinator()
.getStatementPreparer().prepareQueryStatement( sql, callable, scrollMode );
try {
int col = 1;
//TODO: can we limit stored procedures ?!
col += limitHandler.bindLimitParametersAtStartOfQuery( selection, st, col );
if (callable) {
col = dialect.registerResultSetOutParameter( (CallableStatement)st, col );
}
col += bindParameterValues( st, queryParameters, col, session );
col += limitHandler.bindLimitParametersAtEndOfQuery( selection, st, col );
limitHandler.setMaxRows( selection, st );
if ( selection != null ) {
if ( selection.getTimeout() != null ) {
st.setQueryTimeout( selection.getTimeout() );
}
if ( selection.getFetchSize() != null ) {
st.setFetchSize( selection.getFetchSize() );
}
}
// handle lock timeout...
final LockOptions lockOptions = queryParameters.getLockOptions();
if ( lockOptions != null ) {
if ( lockOptions.getTimeOut() != LockOptions.WAIT_FOREVER ) {
if ( !dialect.supportsLockTimeouts() ) {
if ( log.isDebugEnabled() ) {
log.debugf(
"Lock timeout [%s] requested but dialect reported to not support lock timeouts",
lockOptions.getTimeOut()
);
}
}
else if ( dialect.isLockTimeoutParameterized() ) {
st.setInt( col++, lockOptions.getTimeOut() );
}
}
}
if ( log.isTraceEnabled() ) {
log.tracev( "Bound [{0}] parameters total", col );
}
}
catch ( SQLException sqle ) {
session.getJdbcCoordinator().getResourceRegistry().release( st );
session.getJdbcCoordinator().afterStatementExecution();
throw sqle;
}
catch ( HibernateException he ) {
session.getJdbcCoordinator().getResourceRegistry().release( st );
session.getJdbcCoordinator().afterStatementExecution();
throw he;
}
return st;
}
protected ScrollMode getScrollMode(boolean scroll, boolean hasFirstRow, boolean useLimitOffSet, QueryParameters queryParameters) {
final boolean canScroll = getFactory().getSettings().isScrollableResultSetsEnabled();
if ( canScroll ) {
if ( scroll ) {
return queryParameters.getScrollMode();
}
if ( hasFirstRow && !useLimitOffSet ) {
return ScrollMode.SCROLL_INSENSITIVE;
}
}
return null;
}
/**
* Bind all parameter values into the prepared statement in preparation
* for execution.
*
* @param statement The JDBC prepared statement
* @param queryParameters The encapsulation of the parameter values to be bound.
* @param startIndex The position from which to start binding parameter values.
* @param session The originating session.
* @return The number of JDBC bind positions actually bound during this method execution.
* @throws SQLException Indicates problems performing the binding.
*/
protected int bindParameterValues(
PreparedStatement statement,
QueryParameters queryParameters,
int startIndex,
SharedSessionContractImplementor session) throws SQLException {
int span = 0;
span += bindPositionalParameters( statement, queryParameters, startIndex, session );
span += bindNamedParameters( statement, queryParameters.getNamedParameters(), startIndex + span, session );
return span;
}
/**
* Bind positional parameter values to the JDBC prepared statement.
* <p/>
* Positional parameters are those specified by JDBC-style ? parameters
* in the source query. It is (currently) expected that these come
* before any named parameters in the source query.
*
* @param statement The JDBC prepared statement
* @param queryParameters The encapsulation of the parameter values to be bound.
* @param startIndex The position from which to start binding parameter values.
* @param session The originating session.
* @return The number of JDBC bind positions actually bound during this method execution.
* @throws SQLException Indicates problems performing the binding.
* @throws org.hibernate.HibernateException Indicates problems delegating binding to the types.
*/
protected int bindPositionalParameters(
final PreparedStatement statement,
final QueryParameters queryParameters,
final int startIndex,
final SharedSessionContractImplementor session) throws SQLException, HibernateException {
final Object[] values = queryParameters.getFilteredPositionalParameterValues();
final Type[] types = queryParameters.getFilteredPositionalParameterTypes();
int span = 0;
for ( int i = 0; i < values.length; i++ ) {
types[i].nullSafeSet( statement, values[i], startIndex + span, session );
span += types[i].getColumnSpan( getFactory() );
}
return span;
}
/**
* Bind named parameters to the JDBC prepared statement.
* <p/>
* This is a generic implementation, the problem being that in the
* general case we do not know enough information about the named
* parameters to perform this in a complete manner here. Thus this
* is generally overridden on subclasses allowing named parameters to
* apply the specific behavior. The most usual limitation here is that
* we need to assume the type span is always one...
*
* @param statement The JDBC prepared statement
* @param namedParams A map of parameter names to values
* @param startIndex The position from which to start binding parameter values.
* @param session The originating session.
* @return The number of JDBC bind positions actually bound during this method execution.
* @throws SQLException Indicates problems performing the binding.
* @throws org.hibernate.HibernateException Indicates problems delegating binding to the types.
*/
protected int bindNamedParameters(
final PreparedStatement statement,
final Map namedParams,
final int startIndex,
final SharedSessionContractImplementor session) throws SQLException, HibernateException {
if ( namedParams != null ) {
// assumes that types are all of span 1
final Iterator itr = namedParams.entrySet().iterator();
final boolean debugEnabled = log.isDebugEnabled();
int result = 0;
while ( itr.hasNext() ) {
final Map.Entry e = (Map.Entry) itr.next();
final String name = (String) e.getKey();
final TypedValue typedval = (TypedValue) e.getValue();
final int[] locs = getNamedParameterLocs( name );
for ( int loc : locs ) {
if ( debugEnabled ) {
log.debugf(
"bindNamedParameters() %s -> %s [%s]",
typedval.getValue(),
name,
loc + startIndex
);
}
typedval.getType().nullSafeSet( statement, typedval.getValue(), loc + startIndex, session );
}
result += locs.length;
}
return result;
}
else {
return 0;
}
}
/**
* Execute given <tt>PreparedStatement</tt>, advance to the first result and return SQL <tt>ResultSet</tt>.
*/
protected final ResultSet getResultSet(
final PreparedStatement st,
final RowSelection selection,
final LimitHandler limitHandler,
final boolean autodiscovertypes,
final SharedSessionContractImplementor session)
throws SQLException, HibernateException {
try {
ResultSet rs = session.getJdbcCoordinator().getResultSetReturn().extract( st );
rs = wrapResultSetIfEnabled( rs , session );
if ( !limitHandler.supportsLimitOffset() || !LimitHelper.useLimit( limitHandler, selection ) ) {
advance( rs, selection );
}
if ( autodiscovertypes ) {
autoDiscoverTypes( rs );
}
return rs;
}
catch (SQLException | HibernateException ex) {
session.getJdbcCoordinator().getResourceRegistry().release( st );
session.getJdbcCoordinator().afterStatementExecution();
throw ex;
}
}
/**
* Advance the cursor to the first required row of the <tt>ResultSet</tt>
*/
protected void advance(final ResultSet rs, final RowSelection selection) throws SQLException {
final int firstRow = LimitHelper.getFirstRow( selection );
if ( firstRow != 0 ) {
if ( getFactory().getSettings().isScrollableResultSetsEnabled() ) {
// we can go straight to the first required row
rs.absolute( firstRow );
}
else {
// we need to step through the rows one row at a time (slow)
for ( int m = 0; m < firstRow; m++ ) {
rs.next();
}
}
}
}
private ResultSet wrapResultSetIfEnabled(final ResultSet rs, final SharedSessionContractImplementor session) {
if ( session.getFactory().getSessionFactoryOptions().isWrapResultSetsEnabled() ) {
try {
if ( log.isDebugEnabled() ) {
log.debugf( "Wrapping result set [%s]", rs );
}
ResultSetWrapper wrapper = session.getFactory()
.getServiceRegistry()
.getService( JdbcServices.class )
.getResultSetWrapper();
// synchronized to avoid multi-thread access issues
// Apparently the comment about this needing synchronization was introduced when AbstractLoadPlanBasedLoader first appeared
// in version control. Would need to investigate if it's still needed?
synchronized ( this ) {
return wrapper.wrap( rs, retreiveColumnNameToIndexCache( rs ) );
}
}
catch(SQLException e) {
log.unableToWrapResultSet( e );
return rs;
}
}
else {
return rs;
}
}
private ColumnNameCache retreiveColumnNameToIndexCache(ResultSet rs) throws SQLException {
if ( columnNameCache == null ) {
log.trace( "Building columnName->columnIndex cache" );
columnNameCache = new ColumnNameCache( rs.getMetaData().getColumnCount() );
}
return columnNameCache;
}
/**
* Wrapper class for {@link java.sql.Statement} and associated {@link java.sql.ResultSet}.
*/
protected static class SqlStatementWrapper {
private final Statement statement;
private final ResultSet resultSet;
private SqlStatementWrapper(Statement statement, ResultSet resultSet) {
this.resultSet = resultSet;
this.statement = statement;
}
public ResultSet getResultSet() {
return resultSet;
}
public Statement getStatement() {
return statement;
}
}
}