java.lang.Object
- nz.co.gregs.dbvolution.expressions.SortProvider

All Implemented Interfaces:

Serializable, DBExpression, HasSQLString

Direct Known Subclasses:

SortProvider.Ascending, SortProvider.Column, SortProvider.DefaultSort, SortProvider.Descending, SortProvider.NullsOrderer
```
public class SortProvider
extends Object
implements DBExpression, Serializable
```
Provides the sorting expressions used in the ORDER BY clause.
The best way to create a SortProvider is to use the appropriate AnyExpression.ascending() or AnyExpression.descending() method of an expression or column

For instance: myDBRow.column(myDBRow.myDBString).substring(0,2).ascending()

Author:

gregorygraham

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`SortProvider.Ascending`
`static class`	`SortProvider.Column`
`static class`	`SortProvider.DefaultSort`
`static class`	`SortProvider.Descending`
`static class`	`SortProvider.NullsLast`
`static class`	`SortProvider.NullsOrderer`
`static class`	`SortProvider.Ordering`
`static class`	`SortProvider.OrderOfNulls`

Field Summary

Fields
Modifier and Type Field Description

protected SortProvider.Ordering direction

protected SortProvider.OrderOfNulls nullsOrdering

Constructor Summary

Constructors
Modifier	Constructor	Description
`protected`	`SortProvider()`
	`SortProvider(AbstractColumn exp)`
	`SortProvider(QueryColumn<A,B,C> exp)`
`protected`	`SortProvider(AnyExpression<? extends Object,? extends AnyResult<?>,? extends QueryableDatatype<?>> exp, SortProvider.Ordering direction)`
`protected`	`SortProvider(AnyExpression<A,B,C> exp)`
`protected`	`SortProvider(SortProvider sort)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`QueryableDatatype<?>`	`asExpressionColumn()`
`SortProvider`	`copy()`	A Complete Copy Of This DBValue.
`String`	`createSQLForFromClause(DBDatabase database)`
`String`	`createSQLForGroupByClause(DBDatabase database)`
`protected AbstractColumn`	`getColumn()`
`protected String`	`getExpressionSQL(DBDefinition defn)`
`List<String>`	`getGroupByClauses(DBDefinition defn)`
`AnyExpression<? extends Object,? extends AnyResult<?>,? extends QueryableDatatype<?>>`	`getInnerExpression()`
`SortProvider.Ordering`	`getOrdering()`
`QueryableDatatype<?>`	`getQueryableDatatypeForExpressionValue()`	Provides a blank instance of the `QueryableDatatype` used by this expression.
`QueryColumn<?,?,?>`	`getQueryColumn()`
`String`	`getSortDirectionSQL(DBDefinition defn)`	Returns the sort order set for the provider.
`static SortProvider[]`	`getSortProviders(ColumnProvider[] columns)`
`Set<DBRow>`	`getTablesInvolved()`	Returns a Set of the DBRow instances involved in this expression.
`boolean`	`hasColumn()`
`boolean`	`hasInnerExpression()`
`boolean`	`hasQueryColumn()`
`boolean`	`isAggregator()`	Returns TRUE if this expression is an Aggregator like SUM() or LEAST().
`boolean`	`isComplexExpression()`
`boolean`	`isPurelyFunctional()`	Indicates whether or not the expression includes table columns.
`boolean`	`isWindowingFunction()`
`SortProvider`	`nullsFirst()`
`SortProvider`	`nullsHighest()`
`SortProvider`	`nullsLast()`
`SortProvider`	`nullsLowest()`
`void`	`setQueryColumn(QueryColumn<?,? extends AnyResult<?>,?> qc)`
`String`	`toSQLString(DBDefinition defn)`	Produces the snippet provided by this class.
`protected boolean`	`usesEmptyStringForNull(DBDefinition defn)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - direction
```
protected SortProvider.Ordering direction
```
  - nullsOrdering
```
protected SortProvider.OrderOfNulls nullsOrdering
```
- Constructor Detail
  - SortProvider
```
protected SortProvider()
```
  - SortProvider
```
protected SortProvider(SortProvider sort)
```
  - SortProvider
```
protected SortProvider(AnyExpression<A,B,C> exp)
```
  - SortProvider
```
protected SortProvider(AnyExpression<? extends Object,? extends AnyResult<?>,? extends QueryableDatatype<?>> exp,
                       SortProvider.Ordering direction)
```
  - SortProvider
```
public SortProvider(AbstractColumn exp)
```
  - SortProvider
```
public SortProvider(QueryColumn<A,B,C> exp)
```
- Method Detail
  - getSortProviders
```
public static SortProvider[] getSortProviders(ColumnProvider[] columns)
```
  - getGroupByClauses
```
public List<String> getGroupByClauses(DBDefinition defn)
```
  - getQueryableDatatypeForExpressionValue
```
public QueryableDatatype<?> getQueryableDatatypeForExpressionValue()
```
    Description copied from interface: DBExpression
    
    Provides a blank instance of the QueryableDatatype used by this expression.
    You are probably looking for ExpressionColumn.asExpressionColumn().
    Note that this method is not good for use in everyday DBvolution code and should probably be reserved for meta-programming.
    Support DBvolution at Patreon
    
    Specified by:
    
    getQueryableDatatypeForExpressionValue in interface DBExpression
    
    Returns:
    
    the QueryableDatatype subclass that corresponds to the results of this expression
  - isAggregator
```
public boolean isAggregator()
```
    Description copied from interface: DBExpression
    
    Returns TRUE if this expression is an Aggregator like SUM() or LEAST().
    Subclasses must implement this method returning TRUE if the expression will combine the results of several rows to produce a result. If the expression relies on subexpressions, then the isAggregator method must return TRUE if the subexpressions include an aggregator.
    Aggregators collect several rows together to produce a single result. Examples are MAX, MIN, and AVERAGE.
    They are only appropriate in the SELECT clause and generally require the GROUP BY clause to be useful.
    Aggregators are used with DBReport. Aggregator expressions are included in the SELECT clause but excluded from the GROUP BY clause.
    Support DBvolution at Patreon
    
    Specified by:
    
    isAggregator in interface DBExpression
    
    Returns:
    
    TRUE if this DBExpression represents an aggregating functions
  - isWindowingFunction
```
public boolean isWindowingFunction()
```
    Specified by:
    
    isWindowingFunction in interface DBExpression
  - getTablesInvolved
```
public Set<DBRow> getTablesInvolved()
```
    Description copied from interface: DBExpression
    
    Returns a Set of the DBRow instances involved in this expression.
    Used by QueryGraph to plot the connections between tables and avoid cartesian joins.
    Support DBvolution at Patreon
    
    Specified by:
    
    getTablesInvolved in interface DBExpression
    
    Returns:
    
    a set of DBRow instances involved in this DBExpression.
  - isPurelyFunctional
```
public boolean isPurelyFunctional()
```
    Description copied from interface: DBExpression
    
    Indicates whether or not the expression includes table columns.
    Purely functional expressions use only in-built functions or literal values to produce results and do not require data from tables.
    Some databases, notably MS SQLServer, can not group purely functional expressions.
    Support DBvolution at Patreon
    
    Specified by:
    
    isPurelyFunctional in interface DBExpression
    
    Returns:
    
    TRUE if the expression does not access table data, otherwise FALSE.
  - isComplexExpression
```
public boolean isComplexExpression()
```
    Specified by:
    
    isComplexExpression in interface DBExpression
  - createSQLForFromClause
```
public String createSQLForFromClause(DBDatabase database)
```
    Specified by:
    
    createSQLForFromClause in interface DBExpression
  - createSQLForGroupByClause
```
public String createSQLForGroupByClause(DBDatabase database)
```
    Specified by:
    
    createSQLForGroupByClause in interface DBExpression
  - getInnerExpression
```
public AnyExpression<? extends Object,? extends AnyResult<?>,? extends QueryableDatatype<?>> getInnerExpression()
```
    Returns:
    
    the innerExpression
  - hasQueryColumn
```
public boolean hasQueryColumn()
```
  - hasColumn
```
public boolean hasColumn()
```
  - getColumn
```
protected AbstractColumn getColumn()
```
  - setQueryColumn
```
public void setQueryColumn(QueryColumn<?,? extends AnyResult<?>,?> qc)
```
  - getQueryColumn
```
public QueryColumn<?,?,?> getQueryColumn()
```
  - asExpressionColumn
```
public QueryableDatatype<?> asExpressionColumn()
```
  - toSQLString
```
public String toSQLString(DBDefinition defn)
```
    Description copied from interface: HasSQLString
    
    Produces the snippet provided by this class.
    This is only used internally.
    If you are extending DBvolution and adding a new function this is the place to format the information for use in SQL. A DBDefinition instance is provided to supply context and so your SQL can used on multiple database engines.
    
    Specified by:
    
    toSQLString in interface HasSQLString
    
    Parameters:
    
    defn - the target database
    Support DBvolution at Patreon
    
    Returns:
    
    the DBValue formatted as a SQL snippet
  - getExpressionSQL
```
protected String getExpressionSQL(DBDefinition defn)
```
  - usesEmptyStringForNull
```
protected boolean usesEmptyStringForNull(DBDefinition defn)
```
  - hasInnerExpression
```
public boolean hasInnerExpression()
```
  - copy
```
public SortProvider copy()
```
    Description copied from interface: DBExpression
    
    A Complete Copy Of This DBValue.
    Immutability in DBvolution is maintain by internally copying objects.
    This method enables immutability by performing a deep copy of the object.
    Singletons may return themselves but all other objects must return a new instance with copies of all mutable fields.
    Support DBvolution at Patreon
    
    Specified by:
    
    copy in interface DBExpression
    
    Returns:
    
    a copy of this DBValue
  - getSortDirectionSQL
```
public String getSortDirectionSQL(DBDefinition defn)
```
    Returns the sort order set for the provider.
    defaults to ASCENDING
    
    Parameters:
    
    defn - the database definition
    
    Returns:
    
    SQL for the sort direction.
  - getOrdering
```
public SortProvider.Ordering getOrdering()
```
  - nullsLast
```
public SortProvider nullsLast()
```
  - nullsFirst
```
public SortProvider nullsFirst()
```
  - nullsHighest
```
public SortProvider nullsHighest()
```
  - nullsLowest
```
public SortProvider nullsLowest()
```

Modifier and Type	Field	Description
`protected SortProvider.Ordering`	`direction`
`protected SortProvider.OrderOfNulls`	`nullsOrdering`

Class SortProvider

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

direction

nullsOrdering

Constructor Detail

SortProvider

SortProvider

SortProvider

SortProvider

SortProvider

SortProvider

Method Detail

getSortProviders

getGroupByClauses

getQueryableDatatypeForExpressionValue

isAggregator

isWindowingFunction

getTablesInvolved

isPurelyFunctional

isComplexExpression

createSQLForFromClause

createSQLForGroupByClause

getInnerExpression

hasQueryColumn

hasColumn

getColumn

setQueryColumn

getQueryColumn

asExpressionColumn

toSQLString

getExpressionSQL

usesEmptyStringForNull

hasInnerExpression

copy

getSortDirectionSQL

getOrdering

nullsLast

nullsFirst

nullsHighest

nullsLowest