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/**
 *         PlasmaSDO™ License
 * 
 * This is a community release of PlasmaSDO™, a dual-license 
 * Service Data Object (SDO) 2.1 implementation. 
 * This particular copy of the software is released under the 
 * version 2 of the GNU General Public License. PlasmaSDO™ was developed by 
 * TerraMeta Software, Inc.
 * 
 * Copyright (c) 2013, TerraMeta Software, Inc. All rights reserved.
 * 
 * General License information can be found below.
 * 
 * This distribution may include materials developed by third
 * parties. For license and attribution notices for these
 * materials, please refer to the documentation that accompanies
 * this distribution (see the "Licenses for Third-Party Components"
 * appendix) or view the online documentation at 
 * .
 *  
 */
package org.plasma.sdo.jdbc.service;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.plasma.sdo.PlasmaChangeSummary;
import org.plasma.sdo.PlasmaType;
import org.plasma.sdo.core.CoreDataObject;

/**
 * Comparator which imposes a commit ordering on created objects. Note: this
 * comparator imposes orderings that are inconsistent with equals.
 */
public class CreatedCommitComparator extends CommitComparator {

  private static final long serialVersionUID = 1L;
  private static Log log = LogFactory.getFactory().getInstance(CreatedCommitComparator.class);

  public int compare(CoreDataObject source, CoreDataObject target) {

    PlasmaType targetType = (PlasmaType) target.getType();
    PlasmaType sourceType = (PlasmaType) source.getType();
    PlasmaChangeSummary changeSummary = (PlasmaChangeSummary) source.getDataGraph()
        .getChangeSummary();
    int targetDepth = changeSummary.getPathDepth(target);
    int sourceDepth = changeSummary.getPathDepth(source);

    if (targetType.getQualifiedName() != sourceType.getQualifiedName()) {
      if (log.isDebugEnabled())
        log.debug("comparing types: " + sourceType.toString() + " / " + targetType.toString());

      if (isSingularRelation(source, target)) {
        if (log.isDebugEnabled())
          log.debug("(return 1) - singular relation from source: " + sourceType.toString()
              + " to target: " + targetType.toString());
        return 1;
      } else if (isSingularRelation(target, source)) {
        if (log.isDebugEnabled())
          log.debug("(return -1) - singular relation from target: " + targetType.toString()
              + " to source: " + sourceType.toString());
        return -1;
      } else {
        if (log.isDebugEnabled())
          log.debug("(return 0)");
        return 0;
      }
    } else {
      if (log.isDebugEnabled())
        log.debug("comparing data objects : " + source.toString() + " / " + target.toString());
      // give precedence to reference links, then to
      // graph path depth
      if (hasChildLink(source, target)) {
        if (log.isDebugEnabled())
          log.debug("singular link from : " + source.toString() + " to: " + target.toString());
        return 1;
      } else {
        // For say a root object which is part of
        // a tree, where the property e.g. 'parent'
        // is null the above link check won't apply,
        // Therefore rely on graph depth
        if (sourceDepth < targetDepth) {
          if (log.isDebugEnabled())
            log.debug("depth: " + sourceDepth + " / " + targetDepth);
          return -1;
        } else
          return 1;
      }
    }

  }

}