Package org.apache.sis.storage

Class FeatureQuery.NamedExpression

Object

NamedExpression

All Implemented Interfaces:

Serializable

Enclosing class:

Feature­Query

public static class FeatureQuery.NamedExpression
extends Object
implements Serializable

An expression to be retrieved by a Query, together with the name to assign to it. In relational database terminology, subset of columns is called projection. Columns can be given to the Feature­Query.set­Projection(Named­Expression[]) method.

Since:

1.1

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
final Generic­Name	alias	The name to assign to the expression result, or null if unspecified.
final Expression<? super Abstract­Feature,?>	expression	The literal, value reference or more complex expression to be retrieved by a Query.

Constructor Summary

Constructors

Constructor	Description
Named­Expression(Expression<? super Abstract­Feature,?> expression)	Creates a new column with the given expression and no name.
Named­Expression(Expression<? super Abstract­Feature,?> expression, String alias)	Creates a new column with the given expression and the given name.
Named­Expression(Expression<? super Abstract­Feature,?> expression, Generic­Name alias)	Creates a new column with the given expression and the given name.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)	Compares this column with the given object for equality.
int	hash­Code()	Returns a hash code value for this column.
String	to­String()	Returns a string representation of this column for debugging purpose.

Methods inherited from class Object

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

Field Details

expression

public final Expression<? super AbstractFeature,?> expression

The literal, value reference or more complex expression to be retrieved by a Query. Never null.

alias

public final GenericName alias

The name to assign to the expression result, or null if unspecified.

Constructor Details

NamedExpression

public NamedExpression(Expression<? super AbstractFeature,?> expression)

Creates a new column with the given expression and no name.

Parameters:

expression - the literal, value reference or expression to be retrieved by a Query.

NamedExpression

public NamedExpression(Expression<? super AbstractFeature,?> expression,
 GenericName alias)

Creates a new column with the given expression and the given name.

Parameters:

expression - the literal, value reference or expression to be retrieved by a Query.

alias - the name to assign to the expression result, or null if unspecified.

NamedExpression

public NamedExpression(Expression<? super AbstractFeature,?> expression,
 String alias)

Creates a new column with the given expression and the given name. This constructor creates a Local­Name from the given string.

Parameters:

expression - the literal, value reference or expression to be retrieved by a Query.

alias - the name to assign to the expression result, or null if unspecified.

Method Details

hashCode

public int hashCode()

Returns a hash code value for this column.

Overrides:

hash­Code in class Object

Returns:

a hash code value.

equals

public boolean equals(Object obj)

Compares this column with the given object for equality.

Overrides:

equals in class Object

Parameters:

obj - the object to compare with this column.

Returns:

whether the two objects are equal.

toString

public String toString()

Returns a string representation of this column for debugging purpose.

Overrides:

to­String in class Object

Returns:

a string representation of this column.