cascadestyle.java

一个Java持久层类库

//$Id: CascadeStyle.java 10799 2006-11-13 19:34:33Z [e-mail] $
package org.hibernate.engine;

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

import org.hibernate.MappingException;
import org.hibernate.util.ArrayHelper;

/**
 * A contract for defining the aspects of cascading various persistence actions.
 *
 * @see CascadingAction
 *
 * @author Gavin King
 */
public abstract class CascadeStyle implements Serializable {

	/**
	 * For this style, should the given action be cascaded?
	 *
	 * @param action The action to be checked for cascade-ability.
	 * @return True if the action should be cascaded under this style; false otherwise.
	 */
	public abstract boolean doCascade(CascadingAction action);

	/**
	 * Probably more aptly named something like doCascadeToCollectionElements(); it is
	 * however used from both the collection and to-one logic branches...
	 * <p/>
	 * For this style, should the given action really be cascaded?  The default
	 * implementation is simply to return {@link #doCascade}; for certain
	 * styles (currently only delete-orphan), however, we need to be able to
	 * control this seperately.
	 *
	 * @param action The action to be checked for cascade-ability.
	 * @return True if the action should be really cascaded under this style;
	 * false otherwise.
	 */
	public boolean reallyDoCascade(CascadingAction action) {
		return doCascade(action);
	}

	/**
	 * Do we need to delete orphaned collection elements?
	 *
	 * @return True if this style need to account for orphan delete
	 * operations; false othwerwise.
	 */
	public boolean hasOrphanDelete() {
		return false;
	}

	public static final class MultipleCascadeStyle extends CascadeStyle {
		private final CascadeStyle[] styles;
		public MultipleCascadeStyle(CascadeStyle[] styles) {
			this.styles = styles;
		}
		public boolean doCascade(CascadingAction action) {
			for (int i=0; i<styles.length; i++) {
				if ( styles[i].doCascade(action) ) return true;
			}
			return false;
		}
		public boolean reallyDoCascade(CascadingAction action) {
			for (int i=0; i<styles.length; i++) {
				if ( styles[i].reallyDoCascade(action) ) return true;
			}
			return false;
		}
		public boolean hasOrphanDelete() {
			for (int i=0; i<styles.length; i++) {
				if ( styles[i].hasOrphanDelete() ) return true;
			}
			return false;
		}
		public String toString() {
			return ArrayHelper.toString(styles);
		}
	}

	/**
	 * save / delete / update / evict / lock / replicate / merge / persist + delete orphans
	 */
	public static final CascadeStyle ALL_DELETE_ORPHAN = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return true;
		}
		public boolean hasOrphanDelete() {
			return true;
		}
		public String toString() {
			return "STYLE_ALL_DELETE_ORPHAN";
		}
	};

	/**
	 * save / delete / update / evict / lock / replicate / merge / persist
	 */
	public static final CascadeStyle ALL = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return true;
		}
		public String toString() {
			return "STYLE_ALL";
		}
	};

	/**
	 * save / update
	 */
	public static final CascadeStyle UPDATE = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return action==CascadingAction.SAVE_UPDATE || action==CascadingAction.SAVE_UPDATE_COPY;
		}
		public String toString() {
			return "STYLE_SAVE_UPDATE";
		}
	};

	/**
	 * lock
	 */
	public static final CascadeStyle LOCK = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return action==CascadingAction.LOCK;
		}
		public String toString() {
			return "STYLE_LOCK";
		}
	};

	/**
	 * refresh
	 */
	public static final CascadeStyle REFRESH = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return action==CascadingAction.REFRESH;
		}
		public String toString() {
			return "STYLE_REFRESH";
		}
	};

	/**
	 * evict
	 */
	public static final CascadeStyle EVICT = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return action==CascadingAction.EVICT;
		}
		public String toString() {
			return "STYLE_EVICT";
		}
	};

	/**
	 * replicate
	 */
	public static final CascadeStyle REPLICATE = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return action==CascadingAction.REPLICATE;
		}
		public String toString() {
			return "STYLE_REPLICATE";
		}
	};
	/**
	 * merge
	 */
	public static final CascadeStyle MERGE = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return action==CascadingAction.MERGE;
		}
		public String toString() {
			return "STYLE_MERGE";
		}
	};

	/**
	 * create
	 */
	public static final CascadeStyle PERSIST = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return action==CascadingAction.PERSIST
				|| action==CascadingAction.PERSIST_ON_FLUSH;
		}
		public String toString() {
			return "STYLE_PERSIST";
		}
	};

	/**
	 * delete
	 */
	public static final CascadeStyle DELETE = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return action==CascadingAction.DELETE;
		}
		public String toString() {
			return "STYLE_DELETE";
		}
	};

	/**
	 * delete + delete orphans
	 */
	public static final CascadeStyle DELETE_ORPHAN = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return action==CascadingAction.DELETE || action==CascadingAction.SAVE_UPDATE;
		}
		public boolean reallyDoCascade(CascadingAction action) {
			return action==CascadingAction.DELETE;
		}
		public boolean hasOrphanDelete() {
			return true;
		}
		public String toString() {
			return "STYLE_DELETE_ORPHAN";
		}
	};

	/**
	 * no cascades
	 */
	public static final CascadeStyle NONE = new CascadeStyle() {
		public boolean doCascade(CascadingAction action) {
			return false;
		}
		public String toString() {
			return "STYLE_NONE";
		}
	};

	/**
	 * package-protected constructor
	 */
	CascadeStyle() {
	}

	static final Map STYLES = new HashMap();

	static {
		STYLES.put( "all", ALL );
		STYLES.put( "all-delete-orphan", ALL_DELETE_ORPHAN );
		STYLES.put( "save-update", UPDATE );
		STYLES.put( "persist", PERSIST );
		STYLES.put( "merge", MERGE );
		STYLES.put( "lock", LOCK );
		STYLES.put( "refresh", REFRESH );
		STYLES.put( "replicate", REPLICATE );
		STYLES.put( "evict", EVICT );
		STYLES.put( "delete", DELETE );
		STYLES.put( "remove", DELETE ); // adds remove as a sort-of alias for delete...
		STYLES.put( "delete-orphan", DELETE_ORPHAN );
		STYLES.put( "none", NONE );
	}

	/**
	 * Factory method for obtaining named cascade styles
	 *
	 * @param cascade The named cascade style name.
	 * @return The appropriate CascadeStyle
	 */
	public static CascadeStyle getCascadeStyle(String cascade) {
		CascadeStyle style = (CascadeStyle) STYLES.get(cascade);
		if (style==null) {
			throw new MappingException("Unsupported cascade style: " + cascade);
		}
		else {
			return style;
		}
	}
}