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 Details

    • 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 Details

    • 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 Details

    • 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);