# Class PersistentDescriptor

java.lang.Object
org.apache.cayenne.reflect.PersistentDescriptor

All Implemented Interfaces:
  `ClassDescriptor`

public class PersistentDescriptor extends Object implements ClassDescriptor
A default ClassDescriptor implementation for persistent objects.

Since:
  3.0

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected Map<CayennePath, AdditionalDbEntityDescriptor>`
  `additionalDbEntities`
  `protected Collection<ObjAttribute>`
  `allDiscriminatorColumns`
  `protected Map<String, PropertyDescriptor>`
  `declaredProperties`
  `protected ObjEntity`
  `entity`
  `protected EntityInheritanceTree`
  `entityInheritanceTree`
  `protected Expression`
  `entityQualifier`
  `protected Collection<AttributeProperty>`
  `idProperties`
  `protected Collection<ArcProperty>`
  `mapArcProperties`
  `protected Class<?>`
  `objectClass`
  `protected Accessor`
  `persistenceStateAccessor`
  `protected Map<String, PropertyDescriptor>`
  `properties`
  `protected Collection<DbEntity>`
  `rootDbEntities`
  `protected Map<String, ClassDescriptor>`
  `subclassDescriptors`
  `protected ClassDescriptor`
  `superclassDescriptor`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `PersistentDescriptor()`
  Creates a PersistentDescriptor.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `addDeclaredProperty(PropertyDescriptor property)`
  Registers a property.
  `void`
  `addRootDbEntity(DbEntity dbEntity)`
  Adds a root DbEntity to the list of roots, filtering duplicates.
  `void`
  `addSubclassDescriptor(String entityName, ClassDescriptor subclassDescriptor)`
  Adds a subclass descriptor that maps to a given class name.
  `void`
  `addSuperProperty(PropertyDescriptor property)`
  Registers a superclass property.
  `Object`
  `createObject()`
  Creates a new instance of a class described by this object.
  `Map<CayennePath, AdditionalDbEntityDescriptor>`
  `getAdditionalDbEntities()`
  Returns information about additional db entities that is used for this ObjEntity (i.e. for flattened attributes).
  `PropertyDescriptor`
  `getDeclaredProperty(String propertyName)`
  Returns a Java Bean property descriptor matching property name or null if no such property is found.
  `Collection<ObjAttribute>`
  `getDiscriminatorColumns()`
  Returns a collection of ObjAttribute for the described class, its superclasses and subclasses, that participate in inheritance qualifier.
  `ObjEntity`
  `getEntity()`
  Returns an ObjEntity associated with this descriptor.
  `EntityInheritanceTree`
  `getEntityInheritanceTree()`
  `Expression`
  `getEntityQualifier()`
  Returns entity qualifier as a Cayenne expression that includes qualifiers for this entity and all subentities.
  `Collection<AttributeProperty>`
  `getIdProperties()`
  Returns a collection of the properties mapped to id columns.
  `Collection<ArcProperty>`
  `getMapArcProperties()`
  Returns a collection over the arc properties whose reverse arcs are to-many maps.
  `Class<?>`
  `getObjectClass()`
  Returns a class mapped by this descriptor.
  `PropertyDescriptor`
  `getProperty(String propertyName)`
  Recursively looks up property descriptor in this class descriptor and all superclass descriptors.
  `Collection<DbEntity>`
  `getRootDbEntities()`
  Returns a collection of DbEntities that are the root tables for this descriptor's ObjEntity.
  `ClassDescriptor`
  `getSubclassDescriptor(String entityName)`
  Returns the most "specialized" descriptor for a given entity name.
  `ClassDescriptor`
  `getSuperclassDescriptor()`
  Returns a descriptor of the mapped superclass or null if the descriptor's entity sits at the top of inheritance hierarchy.
  `boolean`
  `hasSubclasses()`
  Returns whether this class has persistent subclasses.
  `void`
  `injectValueHolders(Object object)`
  Invokes 'prepareForAccess' of a super descriptor and then invokes 'prepareForAccess' of each declared property.
  `boolean`
  `isFault(Object object)`
  Returns true if an object is not fully resolved.
  `void`
  `removeDeclaredProperty(String propertyName)`
  Removes declared property.
  `void`
  `setDiscriminatorColumns(Collection<ObjAttribute> columns)`
  `void`
  `setEntity(ObjEntity entity)`
  `void`
  `setEntityInheritanceTree(EntityInheritanceTree entityInheritanceTree)`
  `void`
  `setEntityQualifier(Expression entityQualifier)`
  `void`
  `setPersistenceStateAccessor(Accessor persistenceStateAccessor)`
  `void`
  `setSuperclassDescriptor(ClassDescriptor superclassDescriptor)`
  `void`
  `shallowMerge(Object from, Object to)`
  Copies object properties from one object to another.
  `boolean`
  `visitAllProperties(PropertyVisitor visitor)`
  Passes the visitor to the properties "visit" method for a combination of all properties, including properties declared in this descriptor, its super descriptors, and all subdescriptors.
  `boolean`
  `visitDeclaredProperties(PropertyVisitor visitor)`
  Passes the visitor to the properties "visit" method for all properties declared in this descriptor.
  `boolean`
  `visitProperties(PropertyVisitor visitor)`
  Passes the visitor to the properties "visit" method for all properties declared in this descriptor and all its super-decsriptors.

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

  ### Methods inherited from interface ClassDescriptor

  `getSubclassDescriptor`

- ## Field Details

  - ### superclassDescriptor

    protected ClassDescriptor superclassDescriptor

  - ### objectClass

    protected Class<?> objectClass

  - ### declaredProperties

    protected Map<String, PropertyDescriptor> declaredProperties

  - ### properties

    protected Map<String, PropertyDescriptor> properties

  - ### subclassDescriptors

    protected Map<String, ClassDescriptor> subclassDescriptors

  - ### persistenceStateAccessor

    protected Accessor persistenceStateAccessor

  - ### entity

    protected ObjEntity entity

  - ### rootDbEntities

    protected Collection<DbEntity> rootDbEntities

  - ### additionalDbEntities

    protected Map<CayennePath, AdditionalDbEntityDescriptor> additionalDbEntities

  - ### entityInheritanceTree

    protected EntityInheritanceTree entityInheritanceTree

  - ### idProperties

    protected Collection<AttributeProperty> idProperties

  - ### mapArcProperties

    protected Collection<ArcProperty> mapArcProperties

  - ### allDiscriminatorColumns

    protected Collection<ObjAttribute> allDiscriminatorColumns

  - ### entityQualifier

    protected Expression entityQualifier

- ## Constructor Details

  - ### PersistentDescriptor

    public PersistentDescriptor()
    Creates a PersistentDescriptor.

- ## Method Details

  - ### setDiscriminatorColumns

    public void setDiscriminatorColumns(Collection<ObjAttribute> columns)

  - ### addSuperProperty

    public void addSuperProperty(PropertyDescriptor property)
    Registers a superclass property.

  - ### addDeclaredProperty

    public void addDeclaredProperty(PropertyDescriptor property)
    Registers a property. This method is useful to customize default ClassDescriptor generated from ObjEntity by adding new properties or overriding the standard ones.

  - ### addRootDbEntity

    public void addRootDbEntity(DbEntity dbEntity)
    Adds a root DbEntity to the list of roots, filtering duplicates.

  - ### removeDeclaredProperty

    public void removeDeclaredProperty(String propertyName)
    Removes declared property. This method can be used to customize default ClassDescriptor generated from ObjEntity.

  - ### addSubclassDescriptor

    public void addSubclassDescriptor(String entityName, ClassDescriptor subclassDescriptor)
    Adds a subclass descriptor that maps to a given class name.

  - ### getEntity

    public ObjEntity getEntity()
    Description copied from interface: `ClassDescriptor`
    Returns an ObjEntity associated with this descriptor.
    Specified by:
      `getEntity` in interface `ClassDescriptor`

  - ### getRootDbEntities

    public Collection<DbEntity> getRootDbEntities()
    Description copied from interface: `ClassDescriptor`
    Returns a collection of DbEntities that are the root tables for this descriptor's ObjEntity. Usually such collection would contain only one entity, however in cases involving subclass horizontal inheritance, it will be more than one, and in cases of abstract entities with no subclasses, the collection will be empty.
    Specified by:
      `getRootDbEntities` in interface `ClassDescriptor`

  - ### getAdditionalDbEntities

    public Map<CayennePath, AdditionalDbEntityDescriptor> getAdditionalDbEntities()
    Description copied from interface: `ClassDescriptor`
    Returns information about additional db entities that is used for this ObjEntity (i.e. for flattened attributes).

    Keys are full paths for corresponding flattened attributes.

    Specified by:
      `getAdditionalDbEntities` in interface `ClassDescriptor`
    Returns:
      information about additional db entities

  - ### isFault

    public boolean isFault(Object object)
    Description copied from interface: `ClassDescriptor`
    Returns true if an object is not fully resolved.
    Specified by:
      `isFault` in interface `ClassDescriptor`

  - ### getObjectClass

    public Class<?> getObjectClass()
    Description copied from interface: `ClassDescriptor`
    Returns a class mapped by this descriptor.
    Specified by:
      `getObjectClass` in interface `ClassDescriptor`

  - ### getSubclassDescriptor

    public ClassDescriptor getSubclassDescriptor(String entityName)
    Description copied from interface: `ClassDescriptor`
    Returns the most "specialized" descriptor for a given entity name.
    Specified by:
      `getSubclassDescriptor` in interface `ClassDescriptor`

  - ### getDiscriminatorColumns

    public Collection<ObjAttribute> getDiscriminatorColumns()
    Description copied from interface: `ClassDescriptor`
    Returns a collection of ObjAttribute for the described class, its superclasses and subclasses, that participate in inheritance qualifier. If a discriminator expression specifies a DbAttribute instead of an ObjAttribute, a synthetic ObjAttribute is created and returned.
    Specified by:
      `getDiscriminatorColumns` in interface `ClassDescriptor`

  - ### getIdProperties

    public Collection<AttributeProperty> getIdProperties()
    Description copied from interface: `ClassDescriptor`
    Returns a collection of the properties mapped to id columns.
    Specified by:
      `getIdProperties` in interface `ClassDescriptor`

  - ### getMapArcProperties

    public Collection<ArcProperty> getMapArcProperties()
    Description copied from interface: `ClassDescriptor`
    Returns a collection over the arc properties whose reverse arcs are to-many maps. I.e. for each ArcProperty in returned collection, the following is true:

        arc.getComplimentaryReverseArc() instanceof ToManyMapProperty

    Specified by:
      `getMapArcProperties` in interface `ClassDescriptor`

  - ### getProperty

    public PropertyDescriptor getProperty(String propertyName)
    Recursively looks up property descriptor in this class descriptor and all superclass descriptors.
    Specified by:
      `getProperty` in interface `ClassDescriptor`

  - ### getDeclaredProperty

    public PropertyDescriptor getDeclaredProperty(String propertyName)
    Description copied from interface: `ClassDescriptor`
    Returns a Java Bean property descriptor matching property name or null if no such property is found. Lookup DOES NOT including properties from the superclass descriptors. Returned property can be any one of `AttributeProperty`, `ToManyProperty`, `ToOneProperty`.
    Specified by:
      `getDeclaredProperty` in interface `ClassDescriptor`

  - ### getSuperclassDescriptor

    public ClassDescriptor getSuperclassDescriptor()
    Returns a descriptor of the mapped superclass or null if the descriptor's entity sits at the top of inheritance hierarchy.
    Specified by:
      `getSuperclassDescriptor` in interface `ClassDescriptor`

  - ### createObject

    public Object createObject()
    Creates a new instance of a class described by this object.
    Specified by:
      `createObject` in interface `ClassDescriptor`

  - ### injectValueHolders

    public void injectValueHolders(Object object) throws PropertyException
    Invokes 'prepareForAccess' of a super descriptor and then invokes 'prepareForAccess' of each declared property.
    Specified by:
      `injectValueHolders` in interface `ClassDescriptor`
    Throws:
      `PropertyException`

  - ### shallowMerge

    public void shallowMerge(Object from, Object to) throws PropertyException
    Copies object properties from one object to another. Invokes 'shallowCopy' of a super descriptor and then invokes 'shallowCopy' of each declared property.
    Specified by:
      `shallowMerge` in interface `ClassDescriptor`
    Throws:
      `PropertyException`

  - ### visitDeclaredProperties

    public boolean visitDeclaredProperties(PropertyVisitor visitor)
    Description copied from interface: `ClassDescriptor`
    Passes the visitor to the properties "visit" method for all properties declared in this descriptor. This property set excludes inherited properties, even those that got overridden in this subclass. Walkthrough is terminated in case one of the properties returns false. Returns true if all visited properties returned true, false - if one property returned false.
    Specified by:
      `visitDeclaredProperties` in interface `ClassDescriptor`
    Since:
      3.0

  - ### visitAllProperties

    public boolean visitAllProperties(PropertyVisitor visitor)
    Description copied from interface: `ClassDescriptor`
    Passes the visitor to the properties "visit" method for a combination of all properties, including properties declared in this descriptor, its super descriptors, and all subdescriptors. Walkthrough is terminated in case one of the properties returns false. Returns true if all visited properties returned true, false - if one property returned false.
    Specified by:
      `visitAllProperties` in interface `ClassDescriptor`
    Since:
      3.0

  - ### visitProperties

    public boolean visitProperties(PropertyVisitor visitor)
    Description copied from interface: `ClassDescriptor`
    Passes the visitor to the properties "visit" method for all properties declared in this descriptor and all its super-decsriptors. Properties that are overridden in subdescriptors will include overridden information. Walkthrough is terminated in case one of the properties returns false. Returns true if all visited properties returned true, false - if one property returned false.
    Specified by:
      `visitProperties` in interface `ClassDescriptor`

  - ### setPersistenceStateAccessor

    public void setPersistenceStateAccessor(Accessor persistenceStateAccessor)

  - ### setEntity

    public void setEntity(ObjEntity entity)

  - ### setSuperclassDescriptor

    public void setSuperclassDescriptor(ClassDescriptor superclassDescriptor)

  - ### getEntityQualifier

    public Expression getEntityQualifier()
    Description copied from interface: `ClassDescriptor`
    Returns entity qualifier as a Cayenne expression that includes qualifiers for this entity and all subentities.
    Specified by:
      `getEntityQualifier` in interface `ClassDescriptor`

  - ### setEntityQualifier

    public void setEntityQualifier(Expression entityQualifier)

  - ### getEntityInheritanceTree

    public EntityInheritanceTree getEntityInheritanceTree()
    Specified by:
      `getEntityInheritanceTree` in interface `ClassDescriptor`

  - ### setEntityInheritanceTree

    public void setEntityInheritanceTree(EntityInheritanceTree entityInheritanceTree)

  - ### hasSubclasses

    public boolean hasSubclasses()
    Description copied from interface: `ClassDescriptor`
    Returns whether this class has persistent subclasses.
    Specified by:
      `hasSubclasses` in interface `ClassDescriptor`