/*******************************************************************************
 * Copyright (c) 1998, 2013 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the 
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 
 * which accompanies this distribution. 
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at 
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
 *     05/16/2008-1.0M8 Guy Pelletier 
 *       - 218084: Implement metadata merging functionality between mapping files
 *     04/27/2010-2.1 Guy Pelletier 
 *       - 309856: MappedSuperclasses from XML are not being initialized properly
 *     03/24/2011-2.3 Guy Pelletier 
 *       - 337323: Multi-tenant with shared schema support (part 1)
 *      *     30/05/2012-2.4 Guy Pelletier    
 *       - 354678: Temp classloader is still being used during metadata processing
 ******************************************************************************/  
package org.eclipse.persistence.internal.jpa.metadata.accessors.mappings;

import org.eclipse.persistence.descriptors.TimestampLockingPolicy;
import org.eclipse.persistence.descriptors.VersionLockingPolicy;

import org.eclipse.persistence.exceptions.ValidationException;

import org.eclipse.persistence.internal.jpa.metadata.MetadataDescriptor;
import org.eclipse.persistence.internal.jpa.metadata.MetadataLogger;

import org.eclipse.persistence.internal.jpa.metadata.accessors.classes.ClassAccessor;
import org.eclipse.persistence.internal.jpa.metadata.accessors.objects.MetadataAnnotatedElement;
import org.eclipse.persistence.internal.jpa.metadata.accessors.objects.MetadataAnnotation;
import org.eclipse.persistence.internal.jpa.metadata.accessors.objects.MetadataClass;

/**
 * INTERNAL:
 * A basic version accessor.
 * 
 * Key notes:
 * - any metadata mapped from XML to this class must be compared in the
 *   equals method.
 * - any metadata mapped from XML to this class must be handled in the merge
 *   method. (merging is done at the accessor/mapping level)
 * - any metadata mapped from XML to this class must be initialized in the
 *   initXMLObject  method.
 * - methods should be preserved in alphabetical order.
 * 
 * @author Guy Pelletier
 * @since EclipseLink 1.0
 */
public class VersionAccessor extends BasicAccessor {
    /**
     * INTERNAL:
     * Used for OX mapping.
     */
    public VersionAccessor() {
        super("<version>");
    }
    
    /**
     * INTERNAL:
     */
    public VersionAccessor(MetadataAnnotation version, MetadataAnnotatedElement annotatedElement, ClassAccessor classAccessor) {
        super(version, annotatedElement, classAccessor);
    }

    /**
     * INTERNAL:
     */
    @Override
    public boolean equals(Object objectToCompare) {
        return super.equals(objectToCompare) && objectToCompare instanceof VersionAccessor;
    }

    /**
     * INTERNAL:
     * Returns true if the given class is a valid timestamp locking type.
     */
    protected boolean isValidTimestampVersionLockingType(MetadataClass cls) {
        return cls.equals(java.sql.Timestamp.class);
    }
     
    /**
     * INTERNAL:
     * Returns true if the given class is a valid version locking type.
     */
    protected boolean isValidVersionLockingType(MetadataClass cls) {
        return (cls.equals(int.class) ||
                cls.equals(Integer.class) ||
                cls.equals(short.class) ||
                cls.equals(Short.class) ||
                cls.equals(long.class) ||
                cls.equals(Long.class));
    }
    
    /**
     * INTERNAL:
     * Process a version accessor.
     */
    @Override
    public void process() {
        // This will initialize the m_field variable. Accessible through getField().
        super.process();
        
        // Process an @Version or version element if there is one.
        if (getDescriptor().usesOptimisticLocking()) {
            // Ignore the version locking if it is already set.
            getLogger().logConfigMessage(MetadataLogger.IGNORE_VERSION_LOCKING, this);
        } else {
            MetadataClass lockType = getRawClass();
            getDatabaseField().setTypeName(getJavaClassName(lockType));

            if (isValidVersionLockingType(lockType) || isValidTimestampVersionLockingType(lockType)) {
                for (MetadataDescriptor owningDescriptor : getOwningDescriptors()) {
                    VersionLockingPolicy policy = isValidVersionLockingType(lockType) ? new VersionLockingPolicy(getDatabaseField()) : new TimestampLockingPolicy(getDatabaseField());  
                    policy.storeInObject();
                    policy.setIsCascaded(getDescriptor().usesCascadedOptimisticLocking());
                    owningDescriptor.setOptimisticLockingPolicy(policy);
                }
            } else {
                throw ValidationException.invalidTypeForVersionAttribute(getAttributeName(), lockType, getJavaClass());
            }
        }
    }
}
