~ubuntu-branches/ubuntu/wily/libhibernate3-java/wily-proposed

//$Id: ReplicationMode.java 5060 2004-12-24 03:11:05Z oneovthafew $

package org.hibernate;

 

import java.io.Serializable;

import java.util.HashMap;

import java.util.Map;

 

import org.hibernate.type.VersionType;

 

/**

 * Represents a replication strategy.

 *

 * @see Session#replicate(Object, ReplicationMode)

 * @author Gavin King

 */

public abstract class ReplicationMode implements Serializable {

        private final String name;

        private static final Map INSTANCES = new HashMap();

 

        public ReplicationMode(String name) {

                this.name=name;

        }

        public String toString() {

                return name;

        }

        public abstract boolean shouldOverwriteCurrentVersion(Object entity, Object currentVersion, Object newVersion, VersionType versionType);

        /**

         * Throw an exception when a row already exists.

         */

        public static final ReplicationMode EXCEPTION = new ReplicationMode("EXCEPTION") {

                public boolean shouldOverwriteCurrentVersion(Object entity, Object currentVersion, Object newVersion, VersionType versionType) {

                        throw new AssertionFailure("should not be called");

                }

        };

        /**

         * Ignore replicated entities when a row already exists.

         */

        public static final ReplicationMode IGNORE = new ReplicationMode("IGNORE") {

                public boolean shouldOverwriteCurrentVersion(Object entity, Object currentVersion, Object newVersion, VersionType versionType) {

                        return false;

                }

        };

        /**

         * Overwrite existing rows when a row already exists.

         */

        public static final ReplicationMode OVERWRITE = new ReplicationMode("OVERWRITE") {

                public boolean shouldOverwriteCurrentVersion(Object entity, Object currentVersion, Object newVersion, VersionType versionType) {

                        return true;

                }

        };

        /**

         * When a row already exists, choose the latest version.

         */

        public static final ReplicationMode LATEST_VERSION = new ReplicationMode("LATEST_VERSION") {

                public boolean shouldOverwriteCurrentVersion(Object entity, Object currentVersion, Object newVersion, VersionType versionType) {

                        if (versionType==null) return true; //always overwrite nonversioned data

                        return versionType.getComparator().compare(currentVersion, newVersion) <= 0;

                }

        };

 

        static {

                INSTANCES.put( LATEST_VERSION.name, LATEST_VERSION );

                INSTANCES.put( IGNORE.name, IGNORE );

                INSTANCES.put( OVERWRITE.name, OVERWRITE );

                INSTANCES.put( EXCEPTION.name, EXCEPTION );

        }

 

        private Object readResolve() {

                return INSTANCES.get(name);

        }

 

}