Package org.apache.cayenne.exp

Class Property<E>

java.lang.Object

org.apache.cayenne.exp.Property<E>

Type Parameters:

E - The type this property returns.

public class Property<E>
extends Object

A property in a DataObject.

Used to construct Expressions quickly and with type-safety, and to construct Orderings.

Instances of this class are immutable.

Must be created via factory methods Property.create(..)

Since:

4.0

See Also:

create(String, Class), create(Expression, Class), create(String, Expression, Class)

Field Summary

Fields

Modifier and Type	Field	Description
static Property<Long>	COUNT	Property that can be used in COUNT(*) queries

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Property(String name, Class<? super E> type)	Constructs a new property with the given name and type.
protected	Property(String name, Expression expression, Class<? super E> type)	Constructs a new property with the given name and expression

Method Summary

Modifier and Type	Method	Description
Property<E>	abs()
Property<E>	alias(String alias)	Creates alias with different name for this property
Ordering	asc()
Ordering	ascInsensitive()
Orderings	ascInsensitives()
Orderings	ascs()
Property<E>	avg()
Expression	between(E lower, E upper)
Property<String>	concat(Object... args)	Arguments will be converted as follows: if argument is a Property than its expression will be used if argument is a Expression than it will be used as is all other values will be converted to String
Expression	contains(String substring)	Creates an expression for a database "LIKE" query with the value converted to a pattern matching anywhere in the String.
Expression	containsIgnoreCase(String value)	Same as contains(String), only using case-insensitive comparison.
Property<Long>	count()
Property<Long>	countDistinct()
static <T> Property<T>	create(String name, Class<? super T> type)	Creates property with name and type
static <T> Property<T>	create(String name, Expression expression, Class<? super T> type)	Creates property with name, expression and type
static <T> Property<T>	create(Expression expression, Class<? super T> type)	Creates property with expression and type
static <T extends Persistent> Property<T>	createSelf(Class<? super T> type)	Creates "self" Property for persistent class.
Ordering	desc()
Ordering	descInsensitive()
Orderings	descInsensitives()
Orderings	descs()
PrefetchTreeNode	disjoint()	Returns a prefetch tree that follows this property path, potentially spanning a number of phantom nodes, and having a single leaf with "disjoint" prefetch semantics.
PrefetchTreeNode	disjointById()	Returns a prefetch tree that follows this property path, potentially spanning a number of phantom nodes, and having a single leaf with "disjoint by id" prefetch semantics.
Property<Object>	dot(String property)	Constructs a property path by appending the argument to the existing property separated by a dot.
<T> Property<T>	dot(Property<T> property)	Constructs a new property path by appending the argument to the existing property separated by a dot.
Expression	endsWith(String value)	Creates an expression for a database "LIKE" query with the value converted to a pattern matching the tail of a String.
Expression	endsWithIgnoreCase(String value)	Same as endsWith(String), only using case-insensitive comparison.
Expression	eq(E value)
Expression	eq(Property<?> value)
boolean	equals(Object o)
<T extends Persistent> Property<T>	flat(Class<? super T> tClass)	Create new "flat" property for toMany relationship.
String	getAlias()
Expression	getExpression()	This method returns fresh copy of the expression for each call.
E	getFrom(Object bean)	Extracts property value from an object using JavaBean-compatible introspection with one addition - a property can be a dot-separated property name path.
List<E>	getFromAll(Collection<?> beans)	Extracts property value from a collection of objects using JavaBean-compatible introspection with one addition - a property can be a dot-separated property name path.
String	getName()
Class<? super E>	getType()
Expression	gt(E value)
Expression	gt(Property<?> value)
Expression	gte(E value)
Expression	gte(Property<?> value)
int	hashCode()
Expression	in(E firstValue, E... moreValues)
Expression	in(Collection<E> values)
Expression	isFalse()
Expression	isNotNull()
Expression	isNull()
Expression	isTrue()
PrefetchTreeNode	joint()	Returns a prefetch tree that follows this property path, potentially spanning a number of phantom nodes, and having a single leaf with "joint" prefetch semantics.
Property<Integer>	length()
Expression	like(String pattern)
Expression	like(String pattern, char escapeChar)
Expression	likeIgnoreCase(String pattern)
Property<Integer>	locate(String string)
Property<Integer>	locate(Property<? extends String> property)
Property<String>	lower()
Expression	lt(E value)
Expression	lt(Property<?> value)
Expression	lte(E value)
Expression	lte(Property<?> value)
Property<E>	max()
Property<E>	min()
Property<E>	mod(Number number)
Expression	ne(E value)
Expression	ne(Property<?> value)
Expression	nin(E firstValue, E... moreValues)
Expression	nin(Collection<E> values)
Expression	nlike(String value)
Expression	nlikeIgnoreCase(String value)
Property<E>	outer()	Returns a version of this property that represents an OUTER join.
Expression	path()	Converts this property to a path expression.
void	setIn(Object bean, E value)	Sets a property value in 'obj' using JavaBean-compatible introspection with one addition - a property can be a dot-separated property name path.
void	setInAll(Collection<?> beans, E value)	Sets a property value in a collection of objects using JavaBean-compatible introspection with one addition - a property can be a dot-separated property name path.
Property<E>	sqrt()
Expression	startsWith(String value)	Creates an expression for a database "LIKE" query with the value converted to a pattern matching the beginning of a String.
Expression	startsWithIgnoreCase(String value)	Same as startsWith(String), only using case-insensitive comparison.
Property<String>	substring(int offset, int length)
Property<E>	sum()
Property<String>	trim()
Property<String>	upper()

Methods inherited from class java.lang.Object

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

Field Detail

COUNT

public static final Property<Long> COUNT

Property that can be used in COUNT(*) queries

 List<Object[]> result = ObjectSelect
         .columnQuery(Artist.class, Property.COUNT, Artist.ARTIST_NAME)
         .having(Property.COUNT.gt(1L))
         .select(context);
 

Constructor Detail

Property

protected Property(String name,
                   Class<? super E> type)

Constructs a new property with the given name and type.

Parameters:

name - of the property (usually it's obj path)

type - of the property

See Also:

create(String, Class)

Property

protected Property(String name,
                   Expression expression,
                   Class<? super E> type)

Constructs a new property with the given name and expression

Parameters:

name - of the property (will be used as alias for the expression)

expression - expression for property

type - of the property

See Also:

create(String, Expression, Class)

Method Detail

getName

public String getName()

Returns:

Name of the property in the object.

getAlias

public String getAlias()

Returns:

alias for this property

getExpression

public Expression getExpression()

This method returns fresh copy of the expression for each call.

Returns:

expression that represents this Property

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

dot

public Property<Object> dot(String property)

Constructs a property path by appending the argument to the existing property separated by a dot.

Returns:

a newly created Property object.

dot

public <T> Property<T> dot(Property<T> property)

Constructs a new property path by appending the argument to the existing property separated by a dot.

Returns:

a newly created Property object.

outer

public Property<E> outer()

Returns a version of this property that represents an OUTER join. It is up to caller to ensure that the property corresponds to a relationship, as "outer" attributes make no sense.

path

public Expression path()

Converts this property to a path expression. This method is equivalent of getExpression() which is preferred as more generic.

Returns:

a newly created expression.

See Also:

getExpression()

isNull

public Expression isNull()

Returns:

An expression representing null.

isNotNull

public Expression isNotNull()

Returns:

An expression representing a non-null value.

isTrue

public Expression isTrue()

Returns:

An expression representing equality to TRUE.

isFalse

public Expression isFalse()

Returns:

An expression representing equality to FALSE.

eq

public Expression eq(E value)

Returns:

An expression representing equality to a value.

eq

public Expression eq(Property<?> value)

Returns:

An expression representing equality between two attributes (columns).

ne

public Expression ne(E value)

Returns:

An expression representing inequality to a value.

ne

public Expression ne(Property<?> value)

Returns:

An expression representing inequality between two attributes (columns).

like

public Expression like(String pattern)

Parameters:

pattern - a pattern matching property value. Pattern may include "_" and "%" wildcard symbols to match any single character or a sequence of characters. To prevent "_" and "%" from being treated as wildcards, they need to be escaped and escape char passed with like(String, char) method.

Returns:

An expression for a Database "LIKE" query.

like

public Expression like(String pattern,
                       char escapeChar)

Parameters:

pattern - a properly escaped pattern matching property value. Pattern may include "_" and "%" wildcard symbols to match any single character or a sequence of characters.

escapeChar - an escape character used in the pattern to escape "%" and "_".

Returns:

An expression for a Database "LIKE" query.

likeIgnoreCase

public Expression likeIgnoreCase(String pattern)

Returns:

An expression for a case insensitive "LIKE" query.

nlike

public Expression nlike(String value)

Returns:

An expression for a Database "NOT LIKE" query.

nlikeIgnoreCase

public Expression nlikeIgnoreCase(String value)

Returns:

An expression for a case insensitive "NOT LIKE" query.

contains

public Expression contains(String substring)

Creates an expression for a database "LIKE" query with the value converted to a pattern matching anywhere in the String.

Parameters:

substring - a String to match against property value. "_" and "%" symbols are NOT treated as wildcards and are escaped when converted to a LIKE expression.

Returns:

a newly created expression.

startsWith

public Expression startsWith(String value)

Creates an expression for a database "LIKE" query with the value converted to a pattern matching the beginning of a String.

Parameters:

value - a String to match against property value. "_" and "%" symbols are NOT treated as wildcards and are escaped when converted to a LIKE expression.

Returns:

a newly created expression.

endsWith

public Expression endsWith(String value)

Creates an expression for a database "LIKE" query with the value converted to a pattern matching the tail of a String.

Parameters:

value - a String to match against property value. "_" and "%" symbols are NOT treated as wildcards and are escaped when converted to a LIKE expression.

Returns:

a newly created expression.

containsIgnoreCase

public Expression containsIgnoreCase(String value)

Same as contains(String), only using case-insensitive comparison.

startsWithIgnoreCase

public Expression startsWithIgnoreCase(String value)

Same as startsWith(String), only using case-insensitive comparison.

endsWithIgnoreCase

public Expression endsWithIgnoreCase(String value)

Same as endsWith(String), only using case-insensitive comparison.

between

public Expression between(E lower,
                          E upper)

Parameters:

lower - The lower bound.

upper - The upper bound.

Returns:

An expression checking for objects between a lower and upper bound inclusive

in

public Expression in(E firstValue,
                     E... moreValues)

Returns:

An expression for finding objects with values in the given set.

nin

public Expression nin(E firstValue,
                      E... moreValues)

Returns:

An expression for finding objects with values not in the given set.

in

public Expression in(Collection<E> values)

Returns:

An expression for finding objects with values in the given set.

nin

public Expression nin(Collection<E> values)

Returns:

An expression for finding objects with values not in the given set.

gt

public Expression gt(E value)

Returns:

A greater than Expression.

gt

public Expression gt(Property<?> value)

Returns:

Represents a greater than relationship between two attributes (columns).

gte

public Expression gte(E value)

Returns:

A greater than or equal to Expression.

gte

public Expression gte(Property<?> value)

Returns:

Represents a greater than or equal relationship between two attributes (columns).

lt

public Expression lt(E value)

Returns:

A less than Expression.

lt

public Expression lt(Property<?> value)

Returns:

Represents a less than relationship between two attributes (columns).

lte

public Expression lte(E value)

Returns:

A less than or equal to Expression.

lte

public Expression lte(Property<?> value)

Returns:

Represents a less than or equal relationship between two attributes (columns).

asc

public Ordering asc()

Returns:

Ascending sort orderings on this property.

ascs

public Orderings ascs()

Returns:

Ascending sort orderings on this property.

ascInsensitive

public Ordering ascInsensitive()

Returns:

Ascending case insensitive sort orderings on this property.

ascInsensitives

public Orderings ascInsensitives()

Returns:

Ascending case insensitive sort orderings on this property.

desc

public Ordering desc()

Returns:

Descending sort orderings on this property.

descs

public Orderings descs()

Returns:

Descending sort orderings on this property.

descInsensitive

public Ordering descInsensitive()

Returns:

Descending case insensitive sort orderings on this property.

descInsensitives

public Orderings descInsensitives()

Returns:

Descending case insensitive sort orderings on this property.

joint

public PrefetchTreeNode joint()

Returns a prefetch tree that follows this property path, potentially spanning a number of phantom nodes, and having a single leaf with "joint" prefetch semantics.

disjoint

public PrefetchTreeNode disjoint()

Returns a prefetch tree that follows this property path, potentially spanning a number of phantom nodes, and having a single leaf with "disjoint" prefetch semantics.

disjointById

public PrefetchTreeNode disjointById()

Returns a prefetch tree that follows this property path, potentially spanning a number of phantom nodes, and having a single leaf with "disjoint by id" prefetch semantics.

getFrom

public E getFrom(Object bean)

Extracts property value from an object using JavaBean-compatible introspection with one addition - a property can be a dot-separated property name path.

getFromAll

public List<E> getFromAll(Collection<?> beans)

Extracts property value from a collection of objects using JavaBean-compatible introspection with one addition - a property can be a dot-separated property name path.

setIn

public void setIn(Object bean,
                  E value)

Sets a property value in 'obj' using JavaBean-compatible introspection with one addition - a property can be a dot-separated property name path.

setInAll

public void setInAll(Collection<?> beans,
                     E value)

Sets a property value in a collection of objects using JavaBean-compatible introspection with one addition - a property can be a dot-separated property name path.

count

public Property<Long> count()

See Also:

FunctionExpressionFactory.countExp(Expression)

countDistinct

public Property<Long> countDistinct()

Since:

4.1

See Also:

FunctionExpressionFactory.countDistinctExp(Expression)

max

public Property<E> max()

See Also:

FunctionExpressionFactory.maxExp(Expression)

min

public Property<E> min()

See Also:

FunctionExpressionFactory.minExp(Expression)

avg

public Property<E> avg()

See Also:

FunctionExpressionFactory.avgExp(Expression)

sum

public Property<E> sum()

See Also:

FunctionExpressionFactory.sumExp(Expression)

mod

public Property<E> mod(Number number)

See Also:

FunctionExpressionFactory.modExp(Expression, Number)

abs

public Property<E> abs()

See Also:

FunctionExpressionFactory.absExp(Expression)

sqrt

public Property<E> sqrt()

See Also:

FunctionExpressionFactory.sqrtExp(Expression)

length

public Property<Integer> length()

See Also:

FunctionExpressionFactory.lengthExp(Expression)

locate

public Property<Integer> locate(String string)

See Also:

FunctionExpressionFactory.locateExp(String, Expression)

locate

public Property<Integer> locate(Property<? extends String> property)

See Also:

FunctionExpressionFactory.locateExp(Expression, Expression)

trim

public Property<String> trim()

See Also:

FunctionExpressionFactory.trimExp(Expression)

upper

public Property<String> upper()

See Also:

FunctionExpressionFactory.upperExp(Expression)

lower

public Property<String> lower()

See Also:

FunctionExpressionFactory.lowerExp(Expression)

concat

public Property<String> concat(Object... args)

Arguments will be converted as follows:

• if argument is a Property than its expression will be used
• if argument is a Expression than it will be used as is
• all other values will be converted to String

Usage:

     Property<String> fullName = Artist.FIRST_NAME.concat(" ", Artist.SECOND_NAME);
     

See Also:

FunctionExpressionFactory.concatExp(Expression...)

substring

public Property<String> substring(int offset,
                                  int length)

See Also:

FunctionExpressionFactory.substringExp(Expression, int, int)

alias

public Property<E> alias(String alias)

Creates alias with different name for this property

flat

public <T extends Persistent> Property<T> flat(Class<? super T> tClass)

Create new "flat" property for toMany relationship.

Example:

     List<Object[]> result = ObjectSelect
          .columnQuery(Artist.class, Artist.ARTIST_NAME, Artist.PAINTING_ARRAY.flat(Painting.class))
          .select(context);
     

getType

public Class<? super E> getType()

create

public static <T> Property<T> create(String name,
                                     Class<? super T> type)

Creates property with name and type

See Also:

create(Expression, Class), create(String, Expression, Class)

create

public static <T> Property<T> create(Expression expression,
                                     Class<? super T> type)

Creates property with expression and type

See Also:

create(String, Class), create(String, Expression, Class)

create

public static <T> Property<T> create(String name,
                                     Expression expression,
                                     Class<? super T> type)

Creates property with name, expression and type

See Also:

create(String, Class), create(Expression, Class)

createSelf

public static <T extends Persistent> Property<T> createSelf(Class<? super T> type)

Creates "self" Property for persistent class. This property can be used to select full object along with some of it properties (or properties that can be resolved against query root)

Here is sample code, that will select all Artists and count of their Paintings:

     Property<Artist> artistFull = Property.createSelf(Artist.class);
     List<Object[]> result = ObjectSelect
          .columnQuery(Artist.class, artistFull, Artist.PAINTING_ARRAY.count())
          .select(context);