selectclause.java

好东西,hibernate-3.2.0,他是一开元的树杖hibernate-3.2.0

			renderNonScalarSelects( collectSelectExpressions(), fromClause );
		}

		if ( scalarSelect || getWalker().isShallowQuery() ) {
			// If there are any scalars (non-entities) selected, render the select column aliases.
			renderScalarSelects( selectExpressions, fromClause );
		}

		finishInitialization( /*sqlResultTypeList,*/ queryReturnTypeList );
	}

	private void finishInitialization(/*ArrayList sqlResultTypeList,*/ ArrayList queryReturnTypeList) {
		//sqlResultTypes = ( Type[] ) sqlResultTypeList.toArray( new Type[sqlResultTypeList.size()] );
		queryReturnTypes = ( Type[] ) queryReturnTypeList.toArray( new Type[queryReturnTypeList.size()] );
		initializeColumnNames();
		prepared = true;
	}

	private void initializeColumnNames() {
		// Generate an 2d array of column names, the first dimension is parallel with the
		// return types array.  The second dimension is the list of column names for each
		// type.

		// todo: we should really just collect these from the various SelectExpressions, rather than regenerating here
		columnNames = getSessionFactoryHelper().generateColumnNames( queryReturnTypes );
	}

	/**
	 * Prepares a derived (i.e., not explicitly defined in the query) select clause.
	 *
	 * @param fromClause The from clause to which this select clause is linked.
	 */
	public void initializeDerivedSelectClause(FromClause fromClause) throws SemanticException {
		if ( prepared ) {
			throw new IllegalStateException( "SelectClause was already prepared!" );
		}

		//Used to be tested by the TCK but the test is no longer here
//		if ( getSessionFactoryHelper().isStrictJPAQLComplianceEnabled()  && !getWalker().isSubQuery() ) {
//			// NOTE : the isSubQuery() bit is a temporary hack...
//			throw new QuerySyntaxException( "JPA-QL compliance requires select clause" );
//		}
		List fromElements = fromClause.getProjectionList();

		ASTAppender appender = new ASTAppender( getASTFactory(), this );	// Get ready to start adding nodes.
		int size = fromElements.size();
		ArrayList sqlResultTypeList = new ArrayList( size );
		ArrayList queryReturnTypeList = new ArrayList( size );

		Iterator iterator = fromElements.iterator();
		for ( int k = 0; iterator.hasNext(); k++ ) {
			FromElement fromElement = ( FromElement ) iterator.next();
			Type type = fromElement.getSelectType();

			addCollectionFromElement( fromElement );

			if ( type != null ) {
				boolean collectionOfElements = fromElement.isCollectionOfValuesOrComponents();
				if ( !collectionOfElements ) {
					if ( !fromElement.isFetch() ) {
						// Add the type to the list of returned sqlResultTypes.
						queryReturnTypeList.add( type );
					}
					fromElementsForLoad.add( fromElement );
					sqlResultTypeList.add( type );
					// Generate the select expression.
					String text = fromElement.renderIdentifierSelect( size, k );
					SelectExpressionImpl generatedExpr = ( SelectExpressionImpl ) appender.append( SqlTokenTypes.SELECT_EXPR, text, false );
					if ( generatedExpr != null ) {
						generatedExpr.setFromElement( fromElement );
					}
				}
			}
		}

		// Get all the select expressions (that we just generated) and render the select.
		SelectExpression[] selectExpressions = collectSelectExpressions();

		if ( getWalker().isShallowQuery() ) {
			renderScalarSelects( selectExpressions, fromClause );
		}
		else {
			renderNonScalarSelects( selectExpressions, fromClause );
		}
		finishInitialization( /*sqlResultTypeList,*/ queryReturnTypeList );
	}
	
	public static boolean VERSION2_SQL = false;

	private void addCollectionFromElement(FromElement fromElement) {
		if ( fromElement.isFetch() ) {
			if ( fromElement.isCollectionJoin() || fromElement.getQueryableCollection() != null ) {
				String suffix;
				if (collectionFromElements==null) {
					collectionFromElements = new ArrayList();
					suffix = VERSION2_SQL ? "__" : "0__";
				}
				else {
					suffix = Integer.toString( collectionFromElements.size() ) + "__";
				}
				collectionFromElements.add( fromElement );
				fromElement.setCollectionSuffix( suffix );
			}
		}
	}

	protected AST getFirstSelectExpression() {
		AST n = getFirstChild();
		// Skip 'DISTINCT' and 'ALL', so we return the first expression node.
		while ( n != null && ( n.getType() == SqlTokenTypes.DISTINCT || n.getType() == SqlTokenTypes.ALL ) ) {
			n = n.getNextSibling();
		}
		return n;
	}

	private boolean isReturnableEntity(SelectExpression selectExpression) throws SemanticException {
		FromElement fromElement = selectExpression.getFromElement();
		boolean isFetchOrValueCollection = fromElement != null && 
				( fromElement.isFetch() || fromElement.isCollectionOfValuesOrComponents() ); 
		if ( isFetchOrValueCollection ) {
			return false;
		}
		else {
			return selectExpression.isReturnableEntity();
		}
	}

	private void renderScalarSelects(SelectExpression[] se, FromClause currentFromClause) throws SemanticException {
		if ( !currentFromClause.isSubQuery() ) {
			for ( int i = 0; i < se.length; i++ ) {
				SelectExpression expr = se[i];
				expr.setScalarColumnText( i );	// Create SQL_TOKEN nodes for the columns.
			}
		}
	}
	
	private void initAliases(SelectExpression[] selectExpressions) {
		if (constructorNode==null) {
			aliases = new String[selectExpressions.length];
			for ( int i=0; i<selectExpressions.length; i++ ) {
				String alias = selectExpressions[i].getAlias();
				aliases[i] = alias==null ? Integer.toString(i) : alias;
			}
		}
		else {
			aliases = constructorNode.getAliases();
		}
	}

	private void renderNonScalarSelects(SelectExpression[] selectExpressions, FromClause currentFromClause) 
	throws SemanticException {
		ASTAppender appender = new ASTAppender( getASTFactory(), this );
		final int size = selectExpressions.length;
		int nonscalarSize = 0;
		for ( int i = 0; i < size; i++ ) {
			if ( !selectExpressions[i].isScalar() ) nonscalarSize++;
		}

		int j = 0;
		for ( int i = 0; i < size; i++ ) {
			if ( !selectExpressions[i].isScalar() ) {
				SelectExpression expr = selectExpressions[i];
				FromElement fromElement = expr.getFromElement();
				if ( fromElement != null ) {
					renderNonScalarIdentifiers( fromElement, nonscalarSize, j, expr, appender );
					j++;
				}
			}
		}

		if ( !currentFromClause.isSubQuery() ) {
			// Generate the property select tokens.
			int k = 0;
			for ( int i = 0; i < size; i++ ) {
				if ( !selectExpressions[i].isScalar() ) {
					FromElement fromElement = selectExpressions[i].getFromElement();
					if ( fromElement != null ) {
						renderNonScalarProperties( appender, fromElement, nonscalarSize, k );
						k++;
					}
				}
			}
		}
	}

	private void renderNonScalarIdentifiers(FromElement fromElement, int nonscalarSize, int j, SelectExpression expr, ASTAppender appender) {
		String text = fromElement.renderIdentifierSelect( nonscalarSize, j );
		if ( !fromElement.getFromClause().isSubQuery() ) {
			if ( !scalarSelect && !getWalker().isShallowQuery() ) {
				//TODO: is this a bit ugly?
				expr.setText( text );
			}
			else {
				appender.append( SqlTokenTypes.SQL_TOKEN, text, false );
			}
		}
	}

	private void renderNonScalarProperties(ASTAppender appender, FromElement fromElement, int nonscalarSize, int k) {
		String text = fromElement.renderPropertySelect( nonscalarSize, k );
		appender.append( SqlTokenTypes.SQL_TOKEN, text, false );
		if ( fromElement.getQueryableCollection() != null && fromElement.isFetch() ) {
			text = fromElement.renderCollectionSelectFragment( nonscalarSize, k );
			appender.append( SqlTokenTypes.SQL_TOKEN, text, false );
		}
		// Look through the FromElement's children to find any collections of values that should be fetched...
		ASTIterator iter = new ASTIterator( fromElement );
		while ( iter.hasNext() ) {
			FromElement child = ( FromElement ) iter.next();
			if ( child.isCollectionOfValuesOrComponents() && child.isFetch() ) {
				// Need a better way to define the suffixes here...
				text = child.renderValueCollectionSelectFragment( nonscalarSize, nonscalarSize + k );
				appender.append( SqlTokenTypes.SQL_TOKEN, text, false );
			}
		}
	}

	public List getCollectionFromElements() {
		return collectionFromElements;
	}
}