org.apache.cayenne.map
Class Entity

java.lang.Object
  extended by org.apache.cayenne.map.Entity
All Implemented Interfaces:
java.io.Serializable, CayenneMapEntry, XMLSerializable
Direct Known Subclasses:
DbEntity, ObjEntity

public abstract class Entity
extends java.lang.Object
implements CayenneMapEntry, XMLSerializable, java.io.Serializable

An Entity is an abstract descriptor for an entity mapping concept. Entity can represent either a descriptor of database table or a persistent object.

Author:
Andrei Adamchik
See Also:
Serialized Form

Field Summary
protected  java.util.SortedMap attributes
           
protected  DataMap dataMap
           
protected  java.lang.String name
           
static java.lang.String PATH_SEPARATOR
           
protected  java.util.SortedMap relationships
           
 
Constructor Summary
Entity()
          Creates an unnamed Entity.
Entity(java.lang.String name)
          Creates a named Entity.
 
Method Summary
 void addAttribute(Attribute attribute)
          Adds new attribute to the entity, setting its parent entity to be this object.
 void addRelationship(Relationship relationship)
          Adds new relationship to the entity.
 void clearAttributes()
           
 void clearRelationships()
           
 Relationship getAnyRelationship(Entity targetEntity)
          Returns a relationship that has a specified entity as a target.
 Attribute getAttribute(java.lang.String attributeName)
          Returns attribute with name attributeName or null if no attribute with this name exists.
 java.util.SortedMap getAttributeMap()
          Returns an unmodifiable sorted map of entity attributes.
 java.util.Collection getAttributes()
          Returns an unmodifiable collection of entity attributes.
 DataMap getDataMap()
           
 java.lang.String getName()
          Returns entity name.
 java.lang.Object getParent()
          Returns the parent map.
 Relationship getRelationship(java.lang.String relName)
          Returns relationship with name relName.
 java.util.SortedMap getRelationshipMap()
          Returns an unmodifiable map of relationships sorted by name.
 java.util.Collection getRelationships()
          Returns an unmodifiable collection of Relationships that exist in this entity.
 java.lang.Object lastPathComponent(Expression pathExp)
          Convenience method returning the last component in the path iterator.
 void removeAttribute(java.lang.String attrName)
          Removes an attribute named attrName.
 void removeRelationship(java.lang.String relName)
          Removes a relationship named attrName.
abstract  java.util.Iterator resolvePathComponents(Expression pathExp)
          Processes expression pathExp and returns an Iterator of path components that contains a sequence of Attributes and Relationships.
 java.util.Iterator resolvePathComponents(java.lang.String path)
          Returns an Iterator over the path components that contains a sequence of Attributes and Relationships.
 void setDataMap(DataMap dataMap)
          Sets parent DataMap of this entity.
 void setName(java.lang.String name)
           
 void setParent(java.lang.Object parent)
          Stores the parent map.
abstract  Expression translateToRelatedEntity(Expression expression, java.lang.String relationshipPath)
          Translates Expression rooted in this entity to an analogous expression rooted in related entity.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface org.apache.cayenne.util.XMLSerializable
encodeAsXML
 

Field Detail

PATH_SEPARATOR

public static final java.lang.String PATH_SEPARATOR
See Also:
Constant Field Values

name

protected java.lang.String name

dataMap

protected DataMap dataMap

attributes

protected java.util.SortedMap attributes

relationships

protected java.util.SortedMap relationships
Constructor Detail

Entity

public Entity()
Creates an unnamed Entity.


Entity

public Entity(java.lang.String name)
Creates a named Entity.

Method Detail

getName

public java.lang.String getName()
Returns entity name. Name is a unique identifier of the entity within its DataMap.

Specified by:
getName in interface CayenneMapEntry
Returns:
name of this entry.

setName

public void setName(java.lang.String name)

getParent

public java.lang.Object getParent()
Description copied from interface: CayenneMapEntry
Returns the parent map.

Specified by:
getParent in interface CayenneMapEntry

setParent

public void setParent(java.lang.Object parent)
Description copied from interface: CayenneMapEntry
Stores the parent map.

Specified by:
setParent in interface CayenneMapEntry

getDataMap

public DataMap getDataMap()
Returns:
parent DataMap of this entity.

setDataMap

public void setDataMap(DataMap dataMap)
Sets parent DataMap of this entity.


getAttribute

public Attribute getAttribute(java.lang.String attributeName)
Returns attribute with name attributeName or null if no attribute with this name exists.


addAttribute

public void addAttribute(Attribute attribute)
Adds new attribute to the entity, setting its parent entity to be this object. If attribute has no name, IllegalArgumentException is thrown.


removeAttribute

public void removeAttribute(java.lang.String attrName)
Removes an attribute named attrName.


clearAttributes

public void clearAttributes()

getRelationship

public Relationship getRelationship(java.lang.String relName)
Returns relationship with name relName. Will return null if no relationship with this name exists in the entity.


addRelationship

public void addRelationship(Relationship relationship)
Adds new relationship to the entity.


removeRelationship

public void removeRelationship(java.lang.String relName)
Removes a relationship named attrName.


clearRelationships

public void clearRelationships()

getRelationshipMap

public java.util.SortedMap getRelationshipMap()
Returns an unmodifiable map of relationships sorted by name.


getAnyRelationship

public Relationship getAnyRelationship(Entity targetEntity)
Returns a relationship that has a specified entity as a target. If there is more than one relationship for the same target, it is unpredictable which one will be returned.

Since:
1.1

getRelationships

public java.util.Collection getRelationships()
Returns an unmodifiable collection of Relationships that exist in this entity.


getAttributeMap

public java.util.SortedMap getAttributeMap()
Returns an unmodifiable sorted map of entity attributes.


getAttributes

public java.util.Collection getAttributes()
Returns an unmodifiable collection of entity attributes.


translateToRelatedEntity

public abstract Expression translateToRelatedEntity(Expression expression,
                                                    java.lang.String relationshipPath)
Translates Expression rooted in this entity to an analogous expression rooted in related entity.

Since:
1.1

lastPathComponent

public java.lang.Object lastPathComponent(Expression pathExp)
Convenience method returning the last component in the path iterator.

Since:
1.1
See Also:
resolvePathComponents(Expression)

resolvePathComponents

public abstract java.util.Iterator resolvePathComponents(Expression pathExp)
                                                  throws ExpressionException
Processes expression pathExp and returns an Iterator of path components that contains a sequence of Attributes and Relationships. Note that if path is invalid and can not be resolved from this entity, this method will still return an Iterator, but an attempt to read the first invalid path component will result in ExpressionException.

Throws:
ExpressionException

resolvePathComponents

public java.util.Iterator resolvePathComponents(java.lang.String path)
                                         throws ExpressionException
Returns an Iterator over the path components that contains a sequence of Attributes and Relationships. Note that if path is invalid and can not be resolved from this entity, this method will still return an Iterator, but an attempt to read the first invalid path component will result in ExpressionException.

Throws:
ExpressionException


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