public FromElementType(FromElement fromElement,
    EntityPersister persister,
    EntityType entityType) 
{
	       
		this.fromElement = fromElement;
		this.persister = persister;
		this.entityType = entityType;
		if ( persister != null ) {
			fromElement.setText( ( ( Queryable ) persister ).getTableName() + " " + getTableAlias() );
		}
}

 public String getCollectionSuffix() 
{
		return collectionSuffix;
}

 public Type getDataType() 
{
		if ( persister == null ) {
			if ( queryableCollection == null ) {
				return null;
			}
			return queryableCollection.getType();
		}
		else {
			return entityType;
		}
}

 public EntityPersister getEntityPersister() 
{
		return persister;
}

 public JoinSequence getJoinSequence() 
{
		if ( joinSequence != null ) {
			return joinSequence;
		}
		// Class names in the FROM clause result in a JoinSequence (the old FromParser does this).
		if ( persister instanceof Joinable ) {
			Joinable joinable = ( Joinable ) persister;
			return fromElement.getSessionFactoryHelper().createJoinSequence().setRoot( joinable, getTableAlias() );
		}
		else {
			return null;	// TODO: Should this really return null?  If not, figure out something better to do here.
		}
}

 PropertyMapping getPropertyMapping(String propertyName) 
{
		checkInitialized();
		if ( queryableCollection == null ) {		// Not a collection?
			return ( PropertyMapping ) persister;	// Return the entity property mapping.
		}
		// If the property is a special collection property name, return a CollectionPropertyMapping.
		if ( CollectionProperties.isCollectionProperty( propertyName ) ) {
			if ( collectionPropertyMapping == null ) {
				collectionPropertyMapping = new CollectionPropertyMapping( queryableCollection );
			}
			return collectionPropertyMapping;
		}
		if ( queryableCollection.getElementType().isAnyType() ) {
			// collection of < many-to-any/ > mappings...
			// used to circumvent the component-collection check below...
			return queryableCollection;
		}
		if ( queryableCollection.getElementType().isComponentType() ) {
			// Collection of components.
			if ( propertyName.equals( EntityPersister.ENTITY_ID ) ) {
				return ( PropertyMapping ) queryableCollection.getOwnerEntityPersister();
			}
		}
		return queryableCollection;
}

 public Type getPropertyType(String propertyName,
    String propertyPath) 
{
		checkInitialized();
		Type type = null;
		// If this is an entity and the property is the identifier property, then use getIdentifierType().
		//      Note that the propertyName.equals( propertyPath ) checks whether we have a component
		//      key reference, where the component class property name is the same as the
		//      entity id property name; if the two are not equal, this is the case and
		//      we'd need to "fall through" to using the property mapping.
		if ( persister != null && propertyName.equals( propertyPath ) && propertyName.equals( persister.getIdentifierPropertyName() ) ) {
			type = persister.getIdentifierType();
		}
		else {	// Otherwise, use the property mapping.
			PropertyMapping mapping = getPropertyMapping( propertyName );
			type = mapping.toType( propertyPath );
		}
		if ( type == null ) {
			throw new MappingException( "Property " + propertyName + " does not exist in " +
					( ( queryableCollection == null ) ? "class" : "collection" ) + " "
					+ ( ( queryableCollection == null ) ? fromElement.getClassName() : queryableCollection.getRole() ) );
		}
		return type;
}

Returns the type of a property, given it's name (the last part) and the full path.

 public Queryable getQueryable() 
{
		return ( persister instanceof Queryable ) ? ( Queryable ) persister : null;
}

Returns the Hibernate queryable implementation for the HQL class.

 public QueryableCollection getQueryableCollection() 
{
		return queryableCollection;
}

 public Type getSelectType() 
{
		if (entityType==null) return null;
		boolean shallow = fromElement.getFromClause().getWalker().isShallowQuery();
		return TypeFactory.manyToOne( entityType.getAssociatedEntityName(), shallow );
}

 public boolean isCollectionOfValuesOrComponents() 
{
		if ( persister == null ) {
			if ( queryableCollection == null ) {
				return false;
			}
			else {
				return !queryableCollection.getElementType().isEntityType();
			}
		}
		else {
			return false;
		}
}

 public boolean isEntity() 
{
		return persister != null;
}

 String renderCollectionSelectFragment(int size,
    int k) 
{
		if ( queryableCollection == null ) {
			return "";
		}
		else {
			if ( collectionSuffix == null ) {
				collectionSuffix = generateSuffix( size, k );
			}
			String fragment = queryableCollection.selectFragment( getCollectionTableAlias(), collectionSuffix );
			return trimLeadingCommaAndSpaces( fragment );
		}
}

 String renderIdentifierSelect(int size,
    int k) 
{
		checkInitialized();
		// Render the identifier select fragment using the table alias.
		if ( fromElement.getFromClause().isSubQuery() ) {
			// TODO: Replace this with a more elegant solution.
			String[] idColumnNames = ( persister != null ) ?
					( ( Queryable ) persister ).getIdentifierColumnNames() : new String[0];
			StringBuffer buf = new StringBuffer();
			for ( int i = 0; i <  idColumnNames.length; i++ ) {
				buf.append( fromElement.getTableAlias() ).append( '." ).append( idColumnNames[i] );
				if ( i != idColumnNames.length - 1 ) buf.append( ", " );
			}
			return buf.toString();
		}
		else {
			if (persister==null) {
				throw new QueryException( "not an entity" );
			}
			String fragment = ( ( Queryable ) persister ).identifierSelectFragment( getTableAlias(), getSuffix( size, k ) );
			return trimLeadingCommaAndSpaces( fragment );
		}
}

Returns the identifier select SQL fragment.

 String renderPropertySelect(int size,
    int k,
    boolean allProperties) 
{
		checkInitialized();
		if ( persister == null ) {
			return "";
		}
		else {
			String fragment =  ( ( Queryable ) persister ).propertySelectFragment(
					getTableAlias(),
					getSuffix( size, k ),
					allProperties
				);
			return trimLeadingCommaAndSpaces( fragment );
		}
}

Returns the property select SQL fragment.

 String renderScalarIdentifierSelect(int i) 
{
		checkInitialized();
		String[] cols = getPropertyMapping( EntityPersister.ENTITY_ID ).toColumns( getTableAlias(), EntityPersister.ENTITY_ID );
		StringBuffer buf = new StringBuffer();
		// For property references generate < tablealias >.< columnname > as < projectionalias >
		for ( int j = 0; j <  cols.length; j++ ) {
			String column = cols[j];
			if ( j  > 0 ) {
				buf.append( ", " );
			}
			buf.append( column ).append( " as " ).append( NameGenerator.scalarName( i, j ) );
		}
		return buf.toString();
}

Render the identifier select, but in a 'scalar' context (i.e. generate the column alias).

 public String renderValueCollectionSelectFragment(int size,
    int k) 
{
		if ( queryableCollection == null ) {
			return "";
		}
		else {
			if ( collectionSuffix == null ) {
				collectionSuffix = generateSuffix( size, k );
			}
			String fragment =  queryableCollection.selectFragment( getTableAlias(), collectionSuffix );
			return trimLeadingCommaAndSpaces( fragment );
		}
}

 public  void setCollectionSuffix(String suffix) 
{
		collectionSuffix = suffix;
}

 public  void setJoinSequence(JoinSequence joinSequence) 
{
		this.joinSequence = joinSequence;
}

 public  void setQueryableCollection(QueryableCollection queryableCollection) 
{
		if ( this.queryableCollection != null ) {
			throw new IllegalStateException( "QueryableCollection is already defined for " + this + "!" );
		}
		this.queryableCollection = queryableCollection;
		if ( !queryableCollection.isOneToMany() ) {
			// For many-to-many joins, use the tablename from the queryable collection for the default text.
			fromElement.setText( queryableCollection.getTableName() + " " + getTableAlias() );
		}
}

 String[] toColumns(String tableAlias,
    String path,
    boolean inSelect) 
{
		return toColumns( tableAlias, path, inSelect, false );
}

 String[] toColumns(String tableAlias,
    String path,
    boolean inSelect,
    boolean forceAlias) 
{
		checkInitialized();
		PropertyMapping propertyMapping = getPropertyMapping( path );
		// If this from element is a collection and the path is a collection property (maxIndex, etc.) then
		// generate a sub-query.
		if ( !inSelect && queryableCollection != null && CollectionProperties.isCollectionProperty( path ) ) {
			Map enabledFilters = fromElement.getWalker().getEnabledFilters();
			String subquery = CollectionSubqueryFactory.createCollectionSubquery(
					joinSequence,
			        enabledFilters,
					propertyMapping.toColumns( tableAlias, path )
			);
			if ( log.isDebugEnabled() ) {
				log.debug( "toColumns(" + tableAlias + "," + path + ") : subquery = " + subquery );
			}
			return new String[]{"(" + subquery + ")"};
		}
		else {
			if ( forceAlias ) {
				return propertyMapping.toColumns( tableAlias, path );
			}
			else if ( fromElement.getWalker().getStatementType() == HqlSqlTokenTypes.SELECT ) {
				return propertyMapping.toColumns( tableAlias, path );
			}
			else if ( fromElement.getWalker().getCurrentClauseType() == HqlSqlTokenTypes.SELECT ) {
				return propertyMapping.toColumns( tableAlias, path );
			}
			else if ( fromElement.getWalker().isSubQuery() ) {
				// for a subquery, the alias to use depends on a few things (we
				// already know this is not an overall SELECT):
				//      1) if this FROM_ELEMENT represents a correlation to the
				//          outer-most query
				//              A) if the outer query represents a multi-table
				//                  persister, we need to use the given alias
				//                  in anticipation of one of the multi-table
				//                  executors being used (as this subquery will
				//                  actually be used in the "id select" phase
				//                  of that multi-table executor)
				//              B) otherwise, we need to use the persister's
				//                  table name as the column qualification
				//      2) otherwise (not correlated), use the given alias
				if ( isCorrelation() ) {
					if ( isMultiTable() ) {
						return propertyMapping.toColumns( tableAlias, path );
					}
					else {
						return propertyMapping.toColumns( extractTableName(), path );
					}
				}
				else {
					return propertyMapping.toColumns( tableAlias, path );
				}
			}
			else {
				String[] columns = propertyMapping.toColumns( path );
				log.trace( "Using non-qualified column reference [" + path + " - > (" + ArrayHelper.toString( columns ) + ")]" );
				return columns;
			}
		}
}