Package org.teiid.query.sql.lang

Class OrderBy

  • All Implemented Interfaces:
    Cloneable, LanguageObject
    public class OrderBy
extends Object
implements LanguageObject
    Represents the ORDER BY clause of a query. The ORDER BY clause states what order the rows of a result should be returned in. Each element in the ORDER BY represents a sort that is completed in the order listed. The optional keywords ASC and DESC can be put after each element to specify whether the sort is ascending or descending.

    • Constructor Detail

      • OrderBy

        public OrderBy()
        Constructs a default instance of this class.

      • OrderBy

        public OrderBy​(List<? extends Expression> parameters)
        Constructs an instance of this class from an ordered list of elements.
        Parameters:
        parameters - The ordered list of SingleElementSymbol

      • OrderBy

        public OrderBy​(List<? extends Expression> parameters,
               List<Boolean> types)
        Constructs an instance of this class from an ordered set of elements.
        Parameters:
        parameters - The ordered list of SingleElementSymbol
        types - The list of directions by which the results are ordered (Boolean, true=ascending)

    • Method Detail

      • getVariableCount

        public int getVariableCount()
        Returns the number of elements in ORDER BY.
        Returns:
        Number of variables in ORDER BY

      • getVariable

        public Expression getVariable​(int index)
        Returns the ORDER BY element at the specified index.
        Parameters:
        index - Index to get
        Returns:
        The element at the index

      • getOrderType

        public Boolean getOrderType​(int index)
        Returns the sort order at the specified index
        Parameters:
        index - Index to get
        Returns:
        The sort order at the index

      • addVariable

        public OrderByItem addVariable​(Expression element)
        Adds a new variable to the list of order by elements.
        Parameters:
        element - Element to add

      • addVariable

        public OrderByItem addVariable​(Expression element,
                               boolean type)
        Adds a new variable to the list of order by elements with the specified sort order
        Parameters:
        element - Element to add
        type - True for ascending, false for descending

      • acceptVisitor

        public void acceptVisitor​(LanguageVisitor visitor)
        Description copied from interface: LanguageObject
        Method for accepting a visitor. It is the responsibility of the language object to call back on the visitor.
        Specified by:
        acceptVisitor in interface LanguageObject
        Parameters:
        visitor - Visitor being used

      • clone

        public OrderBy clone()
        Return deep copy of this ORDER BY clause.
        Specified by:
        clone in interface LanguageObject
        Overrides:
        clone in class Object
        Returns:
        Deep clone of this object

      • equals

        public boolean equals​(Object obj)
        Compare two OrderBys for equality. Order is important in the order by, so that is considered in the comparison. Also, the sort orders are considered.
        Overrides:
        equals in class Object
        Parameters:
        obj - Other object
        Returns:
        True if equal

      • hashCode

        public int hashCode()
        Get hashcode for OrderBy. WARNING: The hash code relies on the variables in the select, so changing the variables will change the hash code, causing a select to be lost in a hash structure. Do not hash a OrderBy if you plan to change it.
        Overrides:
        hashCode in class Object
        Returns:
        Hash code

      • toString

        public String toString()
        Returns a string representation of an instance of this class.
        Overrides:
        toString in class Object
        Returns:
        String representation of object

      • setExpressionPosition

        public void setExpressionPosition​(int orderIndex,
                                  int selectIndex)

      • getExpressionPosition

        public int getExpressionPosition​(int orderIndex)

      • removeOrderByItem

        public void removeOrderByItem​(int index)

      • hasUnrelated

        public boolean hasUnrelated()

      • getSortKeys

        public List<Expression> getSortKeys()
        Get the list or sort key symbols. Modifications to this list will not add or remove OrderByItems.
        Returns:

      • setUserOrdering

        public void setUserOrdering​(boolean userOrdering)

      • isUserOrdering

        public boolean isUserOrdering()