org.xchain.namespaces.hibernate.PersistCommand.java Source code

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Here is the source code for org.xchain.namespaces.hibernate.PersistCommand.java

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/**
 *    Copyright 2011 meltmedia
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *        http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.xchain.namespaces.hibernate;

import org.apache.commons.jxpath.JXPathContext;
import org.hibernate.Session;
import org.xchain.annotations.Attribute;
import org.xchain.annotations.AttributeType;
import org.xchain.annotations.Element;
import org.xchain.framework.hibernate.HibernateLifecycle;

/**
 * <p>The <code>persist</code> command will execute a Hibernate persist on the session with the specified entity.
 * For more information about the <code>persist</code> method, refer to the Hibernate documentation.</p>
 *
 * <p>This must reference an active <code>session</code>.</p>
 * 
 * <code class="source">
 * &lt;xchain:session xmlns:xchain="http://www.xchain.org/hibernate/1.0"&gt;
 *  &lt;xchain:transaction&gt;
 *    ...
 *    &lt;xchain:persist entity="$myEntity"&gt;
 *    ...
 *  &lt;/xchain:transaction&gt;
 * &lt;/xchain:session&gt;
 * </code>
 *
 * @author Devon Tackett
 * @author Christian Trimble
* 
* @see SessionCommand
* @see org.hibernate.Session#persist(Object)
*/
@Element(localName = "persist")
public abstract class PersistCommand extends AbstractSessionCommand {
    /**
     * The entity to persist. 
     */
    @Attribute(localName = "entity", type = AttributeType.QNAME)
    public abstract String getEntity(JXPathContext context);

    public abstract boolean hasEntity();

    /**
     * Persist the entity at the given QName.  Note that persist will only perform an
     * insert if it is within a transaction.
     */
    public boolean execute(JXPathContext context) throws Exception {
        if (!hasEntity())
            throw new Exception("A persist command must reference an entity.");

        // Get the session from the context.
        Session session = HibernateLifecycle.getCurrentSession(getName(context));

        // Get the entity.
        Object entity = context.getValue(getEntity(context));

        if (entity == null)
            throw new Exception("Unable to find entity at: " + getEntity(context));

        // Perform the persist.
        session.persist(entity);

        // The persist is executed.
        return false;
    }
}