# Class Ordering

java.lang.Object
org.apache.cayenne.query.Ordering

All Implemented Interfaces:
  `Serializable, Comparator<Object>, XMLSerializable`

public class Ordering extends Object implements Comparator<Object>, Serializable, XMLSerializable
Defines object sorting criteria, used either for in-memory sorting of object lists or as a specification for building ORDER BY clause of a SelectQuery query. Note that in case of in-memory sorting, Ordering can be used with any JavaBeans, not just Persistent objects.

See Also:
  - Serialized Form

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected boolean`
  `nullSortedFirst`
  `protected boolean`
  `pathExceptionSuppressed`
  `protected SortOrder`
  `sortOrder`
  `protected Expression`
  `sortSpec`
  `protected String`
  `sortSpecString`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Ordering()`
  `Ordering(String sortPathSpec)`
  Create an ordering instance with a provided path and ascending sorting strategy.
  `Ordering(String sortPathSpec, SortOrder sortOrder)`
  `Ordering(Expression sortSpec)`
  `Ordering(Expression sortSpec, SortOrder sortOrder)`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `int`
  `compare(Object o1, Object o2)`
  Comparable interface implementation.
  `void`
  `encodeAsXML(XMLEncoder encoder, ConfigurationNodeVisitor delegate)`
  Encodes itself as a query ordering.
  `boolean`
  `equals(Object object)`
  `SortOrder`
  `getSortOrder()`
  Returns sort order for this ordering
  `Expression`
  `getSortSpec()`
  Returns the expression defining a ordering Java Bean property.
  `String`
  `getSortSpecString()`
  Returns sortSpec string representation.
  `int`
  `hashCode()`
  `boolean`
  `isAscending()`
  Returns true if sorting is done in ascending order.
  `boolean`
  `isCaseInsensitive()`
  Returns true if the sorting is case insensitive
  `boolean`
  `isCaseSensitive()`
  Returns true if the sorting is case sensitive.
  `boolean`
  `isDescending()`
  Returns true if the sorting is done in descending order.
  `boolean`
  `isNullSortedFirst()`
  Get sort order for nulls.
  `boolean`
  `isPathExceptionSuppressed()`
  Is a path with a null in the middle is ignored.
  `<E> List<E>`
  `orderedList(Collection<E> objects)`
  `static <E> List<E>`
  `orderedList(Collection<E> objects, List<? extends Ordering> orderings)`
  Orders a given list of objects, using a List of Orderings applied according the default iteration order of the Orderings list.
  `void`
  `orderList(List<?> objects)`
  Orders the given list of objects according to the ordering that this object specifies.
  `static void`
  `orderList(List<?> objects, List<? extends Ordering> orderings)`
  Orders a given list of objects, using a List of Orderings applied according the default iteration order of the Orderings list.
  `void`
  `setAscending()`
  If the sort order is DESCENDING or DESCENDING_INSENSITIVE, sets the sort order to ASCENDING or ASCENDING_INSENSITIVE, respectively.
  `void`
  `setCaseInsensitive()`
  If the sort order is ASCENDING or DESCENDING, sets the sort order to ASCENDING_INSENSITIVE or DESCENDING_INSENSITIVE, respectively.
  `void`
  `setCaseSensitive()`
  If the sort order is ASCENDING_INSENSITIVE or DESCENDING_INSENSITIVE, sets the sort order to ASCENDING or DESCENDING, respectively.
  `void`
  `setDescending()`
  If the sort order is ASCENDING or ASCENDING_INSENSITIVE, sets the sort order to DESCENDING or DESCENDING_INSENSITIVE, respectively.
  `void`
  `setNullSortedFirst(boolean nullSortedFirst)`
  Sets sort order for whether nulls are at the top or bottom of the resulting list.
  `void`
  `setPathExceptionSupressed(boolean pathExceptionSuppressed)`
  Sets whether a path with a null in the middle is ignored.
  `void`
  `setSortOrder(SortOrder order)`
  Sets the sort order for this ordering.
  `void`
  `setSortSpec(Expression sortSpec)`
  Sets the expression defining a ordering Java Bean property.
  `void`
  `setSortSpecString(String sortSpecString)`
  Sets sortSpec to be an expression represented by string argument.
  `Orderings`
  `then(List<Ordering> nextOrderings)`
  `Orderings`
  `then(Ordering nextOrdering)`
  Returns Orderings with this Ordering followed by the provided next Ordering.
  `Orderings`
  `then(Orderings nextOrderings)`
  Returns Orderings with this Ordering followed by the provided list of next Orderings.
  `String`
  `toString()`

  ### Methods inherited from class Object

  `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

  ### Methods inherited from interface Comparator

  `reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong`

- ## Field Details

  - ### sortSpecString

    protected String sortSpecString

  - ### sortSpec

    protected transient Expression sortSpec

  - ### sortOrder

    protected SortOrder sortOrder

  - ### pathExceptionSuppressed

    protected boolean pathExceptionSuppressed

  - ### nullSortedFirst

    protected boolean nullSortedFirst

- ## Constructor Details

  - ### Ordering

    public Ordering()

  - ### Ordering

    public Ordering(String sortPathSpec)
    Create an ordering instance with a provided path and ascending sorting strategy.
    Since:
      4.0

  - ### Ordering

    public Ordering(String sortPathSpec, SortOrder sortOrder)
    Since:
      3.0

  - ### Ordering

    public Ordering(Expression sortSpec)
    Since:
      4.0

  - ### Ordering

    public Ordering(Expression sortSpec, SortOrder sortOrder)
    Since:
      4.0

- ## Method Details

  - ### orderList

    public static void orderList(List<?> objects, List<? extends Ordering> orderings)
    Orders a given list of objects, using a List of Orderings applied according the default iteration order of the Orderings list. I.e. each Ordering with lower index is more significant than any other Ordering with higher index. List being ordered is modified in place.
    Parameters:
      `objects` - elements to sort
      `orderings` - list of Orderings to be applied

  - ### orderedList

    public static <E> List<E> orderedList(Collection<E> objects, List<? extends Ordering> orderings)
    Orders a given list of objects, using a List of Orderings applied according the default iteration order of the Orderings list. I.e. each Ordering with lower index is more significant than any other Ordering with higher index.
    Parameters:
      `objects` - elements to sort
      `orderings` - list of Orderings to be applied
    Returns:
      new List with ordered elements
    Since:
      4.0

  - ### equals

    public boolean equals(Object object)
    Specified by:
      `equals` in interface `Comparator<Object>`
    Overrides:
      `equals` in class `Object`

  - ### hashCode

    public int hashCode()
    Overrides:
      `hashCode` in class `Object`

  - ### setSortSpecString

    public void setSortSpecString(String sortSpecString)
    Sets sortSpec to be an expression represented by string argument.
    Since:
      1.1

  - ### setNullSortedFirst

    public void setNullSortedFirst(boolean nullSortedFirst)
    Sets sort order for whether nulls are at the top or bottom of the resulting list. Default is true. Affects only in-memory sorting.
    Parameters:
      `nullSortedFirst` - true sorts nulls to the top of the list, false sorts nulls to the bottom

  - ### isNullSortedFirst

    public boolean isNullSortedFirst()
    Get sort order for nulls.
    Returns:
      true if nulls are sorted to the top of the list, false if sorted to the bottom

  - ### setPathExceptionSupressed

    public void setPathExceptionSupressed(boolean pathExceptionSuppressed)
    Sets whether a path with a null in the middle is ignored. For example, a sort from `painting` on `artist.name` would by default throw an exception if the artist was null. If set to true, then this is treated just like a null value. Default is false.
    Parameters:
      `pathExceptionSuppressed` - true to suppress exceptions and sort as null

  - ### isPathExceptionSuppressed

    public boolean isPathExceptionSuppressed()
    Is a path with a null in the middle is ignored.
    Returns:
      true is exception is suppressed and sorted as null

  - ### getSortSpecString

    public String getSortSpecString()
    Returns sortSpec string representation.
    Since:
      1.1

  - ### setSortOrder

    public void setSortOrder(SortOrder order)
    Sets the sort order for this ordering.
    Since:
      3.0

  - ### isAscending

    public boolean isAscending()
    Returns true if sorting is done in ascending order.

  - ### isDescending

    public boolean isDescending()
    Returns true if the sorting is done in descending order.
    Since:
      3.0

  - ### setAscending

    public void setAscending()
    If the sort order is DESCENDING or DESCENDING_INSENSITIVE, sets the sort order to ASCENDING or ASCENDING_INSENSITIVE, respectively.
    Since:
      3.0

  - ### setDescending

    public void setDescending()
    If the sort order is ASCENDING or ASCENDING_INSENSITIVE, sets the sort order to DESCENDING or DESCENDING_INSENSITIVE, respectively.
    Since:
      3.0

  - ### isCaseInsensitive

    public boolean isCaseInsensitive()
    Returns true if the sorting is case insensitive

  - ### isCaseSensitive

    public boolean isCaseSensitive()
    Returns true if the sorting is case sensitive.
    Since:
      3.0

  - ### setCaseInsensitive

    public void setCaseInsensitive()
    If the sort order is ASCENDING or DESCENDING, sets the sort order to ASCENDING_INSENSITIVE or DESCENDING_INSENSITIVE, respectively.
    Since:
      3.0

  - ### setCaseSensitive

    public void setCaseSensitive()
    If the sort order is ASCENDING_INSENSITIVE or DESCENDING_INSENSITIVE, sets the sort order to ASCENDING or DESCENDING, respectively.
    Since:
      3.0

  - ### getSortSpec

    public Expression getSortSpec()
    Returns the expression defining a ordering Java Bean property.

  - ### setSortSpec

    public void setSortSpec(Expression sortSpec)
    Sets the expression defining a ordering Java Bean property.

  - ### orderList

    public void orderList(List<?> objects)
    Orders the given list of objects according to the ordering that this object specifies. List is modified in-place.
    Parameters:
      `objects` - a List of objects to be sorted

  - ### orderedList

    public <E> List<E> orderedList(Collection<E> objects)
    Since:
      4.0

  - ### compare

    public int compare(Object o1, Object o2)
    Comparable interface implementation. Can compare two Java Beans based on the stored expression.
    Specified by:
      `compare` in interface `Comparator<Object>`

  - ### encodeAsXML

    public void encodeAsXML(XMLEncoder encoder, ConfigurationNodeVisitor delegate)
    Encodes itself as a query ordering.
    Specified by:
      `encodeAsXML` in interface `XMLSerializable`
    Since:
      1.1

  - ### toString

    public String toString()
    Overrides:
      `toString` in class `Object`

  - ### getSortOrder

    public SortOrder getSortOrder()
    Returns sort order for this ordering
    Since:
      3.1

  - ### then

    public Orderings then(Ordering nextOrdering)
    Returns Orderings with this Ordering followed by the provided next Ordering.
    Parameters:
      `nextOrdering` - the next Ordering to chain to this
    Returns:
      a new Orderings with both Ordering
    Since:
      4.1

  - ### then

    public Orderings then(Orderings nextOrderings)
    Returns Orderings with this Ordering followed by the provided list of next Orderings.
    Parameters:
      `nextOrderings` - the next Orderings to chain to this
    Returns:
      an array of sort orderings
    Since:
      4.1

  - ### then

    public Orderings then(List<Ordering> nextOrderings)
    Parameters:
      `nextOrderings` - the next Orderings to chain to this
    Returns:
      an array of sort orderings
    Since:
      4.1
    See Also:
      - `Orderings.then(Orderings)`