cascades.java

hibernate-3.0.5 中文文档

//$Id: Cascades.java,v 1.39 2005/05/05 02:41:21 oneovthafew Exp $
package org.hibernate.engine;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.EntityMode;
import org.hibernate.HibernateException;
import org.hibernate.LockMode;
import org.hibernate.MappingException;
import org.hibernate.ReplicationMode;
import org.hibernate.collection.PersistentCollection;
import org.hibernate.id.IdentifierGeneratorFactory;
import org.hibernate.persister.collection.CollectionPersister;
import org.hibernate.persister.entity.EntityPersister;
import org.hibernate.type.AbstractComponentType;
import org.hibernate.type.AssociationType;
import org.hibernate.type.EntityType;
import org.hibernate.type.CollectionType;
import org.hibernate.type.Type;
import org.hibernate.util.ArrayHelper;

/**
 * Implements cascaded save / delete / update / lock / evict / replicate / persist / merge
 *
 * @see org.hibernate.type.AssociationType
 * @author Gavin King
 */
public final class Cascades {

	private Cascades() {}

	private static final Log log = LogFactory.getLog(Cascades.class);

	// The available cascade actions:

	/**
	 * A session action that may be cascaded from parent entity to its children
	 */
	public abstract static class CascadingAction {
		protected CascadingAction() {}
		/**
		 * cascade the action to the child object
		 */
		abstract void cascade(SessionImplementor session, Object child, String entityName, Object anything, boolean isCascadeDeleteEnabled) 
		throws HibernateException;
		/**
		 * Should this action be cascaded to the given (possibly uninitialized) collection?
		 */
		abstract Iterator getCascadableChildrenIterator(SessionImplementor session, CollectionType collectionType, Object collection);
		/**
		 * Do we need to handle orphan delete for this action?
		 */
		abstract boolean deleteOrphans();
	}

	/**
	 * @see org.hibernate.Session#delete(Object)
	 */
	public static final CascadingAction ACTION_DELETE = new CascadingAction() {
		void cascade(SessionImplementor session, Object child, String entityName, Object anything, boolean isCascadeDeleteEnabled) 
		throws HibernateException {
			if ( log.isTraceEnabled() ) log.trace("cascading to delete: " + entityName);
			if ( ForeignKeys.isNotTransient(entityName, child, null, session) ) session.delete(entityName, child, isCascadeDeleteEnabled);
		}
		Iterator getCascadableChildrenIterator(SessionImplementor session, CollectionType collectionType, Object collection) {
			// delete does cascade to uninitialized collections
			return getAllElementsIterator(session, collectionType, collection);
		}
		boolean deleteOrphans() {
			// orphans should be deleted during delete
			return true;
		}
		public String toString() {
			return "ACTION_DELETE";
		}
	};

	/**
	 * @see org.hibernate.Session#lock(Object, LockMode)
	 */
	public static final CascadingAction ACTION_LOCK = new CascadingAction() {
		void cascade(SessionImplementor session, Object child, String entityName, Object anything, boolean isCascadeDeleteEnabled) 
		throws HibernateException {
			if ( log.isTraceEnabled() ) log.trace("cascading to lock: " + entityName);
			session.lock( entityName, child, LockMode.NONE/*(LockMode) anything*/ );
		}
		Iterator getCascadableChildrenIterator(SessionImplementor session, CollectionType collectionType, Object collection) {
			// lock doesn't cascade to uninitialized collections
			return getLoadedElementsIterator(session, collectionType, collection);
		}
		boolean deleteOrphans() {
			//TODO: should orphans really be deleted during lock???
			return false;
		}
		public String toString() {
			return "ACTION_LOCK";
		}
	};

	/**
	 * @see org.hibernate.Session#refresh(Object)
	 */
	public static final CascadingAction ACTION_REFRESH = new CascadingAction() {
		void cascade(SessionImplementor session, Object child, String entityName, Object anything, boolean isCascadeDeleteEnabled) 
		throws HibernateException {
			if ( log.isTraceEnabled() ) log.trace("cascading to refresh: " + entityName);
			session.refresh(child);
		}
		Iterator getCascadableChildrenIterator(SessionImplementor session, CollectionType collectionType, Object collection) {
			// refresh doesn't cascade to uninitialized collections
			return getLoadedElementsIterator(session, collectionType, collection);
		}
		boolean deleteOrphans() {
			return false;
		}
		public String toString() {
			return "ACTION_REFRESH";
		}
	};

	/**
	 * @see org.hibernate.Session#evict(Object)
	 */
	public static final CascadingAction ACTION_EVICT = new CascadingAction() {
		void cascade(SessionImplementor session, Object child, String entityName, Object anything, boolean isCascadeDeleteEnabled) 
		throws HibernateException {
			if ( log.isTraceEnabled() ) log.trace("cascading to evict: " + entityName);
			session.evict(child);
		}
		Iterator getCascadableChildrenIterator(SessionImplementor session, CollectionType collectionType, Object collection) {
			// evicts don't cascade to uninitialized collections
			return getLoadedElementsIterator(session, collectionType, collection);
		}
		boolean deleteOrphans() {
			return false;
		}
		public String toString() {
			return "ACTION_EVICT";
		}
	};

	/**
	 * @see org.hibernate.Session#saveOrUpdate(Object)
	 */
	public static final CascadingAction ACTION_SAVE_UPDATE = new CascadingAction() {
		void cascade(SessionImplementor session, Object child, String entityName, Object anything, boolean isCascadeDeleteEnabled) 
		throws HibernateException {
			if ( log.isTraceEnabled() ) log.trace("cascading to saveOrUpdate: " + entityName);
			session.saveOrUpdate(entityName, child);
		}
		Iterator getCascadableChildrenIterator(SessionImplementor session, CollectionType collectionType, Object collection) {
			// saves / updates don't cascade to uninitialized collections
			return getLoadedElementsIterator(session, collectionType, collection);
		}
		boolean deleteOrphans() {
			// orphans should be deleted during save/update
			return true;
		}
		public String toString() {
			return "ACTION_SAVE_UPDATE";
		}
	};

	/**
	 * @see org.hibernate.Session#merge(Object)
	 */
	public static final CascadingAction ACTION_MERGE = new CascadingAction() {
		void cascade(SessionImplementor session, Object child, String entityName, Object anything, boolean isCascadeDeleteEnabled) 
		throws HibernateException {
			if ( log.isTraceEnabled() ) log.trace("cascading to merge: " + entityName);
			session.merge( entityName, child, (Map) anything );
		}
		Iterator getCascadableChildrenIterator(SessionImplementor session, CollectionType collectionType, Object collection) {
			// saves / updates don't cascade to uninitialized collections
			return getLoadedElementsIterator(session, collectionType, collection);
		}
		boolean deleteOrphans() {
			// orphans should not be deleted during copy??
			return false;
		}
		public String toString() {
			return "ACTION_MERGE";
		}
	};

	/**
	 * @see org.hibernate.classic.Session#saveOrUpdateCopy(Object)
	 */
	public static final CascadingAction ACTION_SAVE_UPDATE_COPY = new CascadingAction() {
		// for deprecated saveOrUpdateCopy()
		void cascade(SessionImplementor session, Object child, String entityName, Object anything, boolean isCascadeDeleteEnabled) 
		throws HibernateException {
			if ( log.isTraceEnabled() ) log.trace("cascading to saveOrUpdateCopy: " + entityName);
			session.saveOrUpdateCopy( entityName, child, (Map) anything );
		}
		Iterator getCascadableChildrenIterator(SessionImplementor session, CollectionType collectionType, Object collection) {
			// saves / updates don't cascade to uninitialized collections
			return getLoadedElementsIterator(session, collectionType, collection);
		}
		boolean deleteOrphans() {
			// orphans should not be deleted during copy??
			return false;
		}
		public String toString() {
			return "ACTION_SAVE_UPDATE_COPY";
		}
	};

	/**
	 * @see org.hibernate.Session#persist(Object)
	 */
	public static final CascadingAction ACTION_PERSIST = new CascadingAction() {
		void cascade(SessionImplementor session, Object child, String entityName, Object anything, boolean isCascadeDeleteEnabled) 
		throws HibernateException {
			if ( log.isTraceEnabled() ) log.trace("cascading to persist: " + entityName);
			session.persist( entityName, child, (Map) anything );
		}
		Iterator getCascadableChildrenIterator(SessionImplementor session, CollectionType collectionType, Object collection) {
			// saves / updates don't cascade to uninitialized collections
			return getAllElementsIterator(session, collectionType, collection);
		}
		boolean deleteOrphans() {
			// orphans should not be deleted during create
			return false;
		}
		public String toString() {
			return "ACTION_PERSIST";
		}
	};

	public static final CascadingAction ACTION_REPLICATE = new CascadingAction() {
		void cascade(SessionImplementor session, Object child, String entityName, Object anything, boolean isCascadeDeleteEnabled) 
		throws HibernateException {
			if ( log.isTraceEnabled() ) log.trace("cascading to replicate: " + entityName);
			session.replicate( entityName, child, (ReplicationMode) anything );
		}
		Iterator getCascadableChildrenIterator(SessionImplementor session, CollectionType collectionType, Object collection) {
			// replicate does cascade to uninitialized collections
			return getLoadedElementsIterator(session, collectionType, collection);
		}
		boolean deleteOrphans() {
			return false; //I suppose?
		}
		public String toString() {
			return "ACTION_REPLICATE";
		}
	};

	private static boolean collectionIsInitialized(Object collection) {
		return !(collection instanceof PersistentCollection) || ( (PersistentCollection) collection ).wasInitialized();
	}

	// The types of children to cascade to:

	/**
	 * A cascade point that occurs just after the insertion of the parent entity and
	 * just before deletion
	 */
	public static final int CASCADE_AFTER_INSERT_BEFORE_DELETE = 1;
	/**
	 * A cascade point that occurs just before the insertion of the parent entity and
	 * just after deletion
	 */
	public static final int CASCADE_BEFORE_INSERT_AFTER_DELETE = 2;
	/**
	 * A cascade point that occurs just after the insertion of the parent entity and
	 * just before deletion, inside a collection
	 */
	public static final int CASCADE_AFTER_INSERT_BEFORE_DELETE_VIA_COLLECTION = 3;
	/**
	 * A cascade point that occurs just after update of the parent entity
	 */
	public static final int CASCADE_AFTER_UPDATE = 0;
	/**
	 * A cascade point that occurs just before the session is flushed
	 */
	public static final int CASCADE_BEFORE_FLUSH = 0;
	/**
	 * A cascade point that occurs just after eviction of the parent entity from the
	 * session cache
	 */
	public static final int CASCADE_AFTER_EVICT = 0;
	/**
	 * A cascade point that occurs just after locking a transient parent entity into the
	 * session cache
	 */
	public static final int CASCADE_AFTER_REFRESH = 0;
	/**
	 * A cascade point that occurs just after refreshing a parent entity
	 */
	public static final int CASCADE_AFTER_LOCK = 0;
	/**
	 * A cascade point that occurs just before merging from a transient parent entity into
	 * the object in the session cache
	 */
	public static final int CASCADE_BEFORE_MERGE = 0;

	// The allowable cascade styles for a property:

	/**
	 * A style of cascade that can be specified by the mapping for an association.
	 * The style is specified by the <tt>cascade</tt> attribute in the mapping file.
	 */
	public abstract static class CascadeStyle implements Serializable {
		protected CascadeStyle() {}
		/**
		 * Should the given action be cascaded?
		 */
		abstract boolean doCascade(CascadingAction action);
		/**
		 * Should the given action really, really be cascaded?
		 */
		boolean reallyDoCascade(CascadingAction action) {
			return doCascade(action);
		}
		/**
		 * Do we need to delete orphaned collection elements?
		 */
		boolean hasOrphanDelete() {
			return false;
		}
	}
	
	public static final class MultipleCascadeStyle extends CascadeStyle {
		private final CascadeStyle[] styles;
		public MultipleCascadeStyle(CascadeStyle[] styles) {
			this.styles = styles;
		}
		boolean doCascade(CascadingAction action) {
			for (int i=0; i<styles.length; i++) {