Java tutorial
/** * 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 * <http://plasma-sdo.org/licenses/>. * */ package org.plasma.sdo.access.provider.common; import java.io.Serializable; import java.util.Comparator; import java.util.List; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.plasma.sdo.PlasmaChangeSummary; import org.plasma.sdo.PlasmaNode; import commonj.sdo.ChangeSummary; import commonj.sdo.DataObject; import commonj.sdo.Property; /** * Compares its two data-objects for order within the context of data-store * commit operations. * */ public class DataObjectCommitComparator implements Comparator<DataObject>, Serializable { private static Log log = LogFactory.getFactory().getInstance(DataObjectCommitComparator.class); /** * Returns a negative integer, * zero, or a positive integer as the first argument is less * than, equal to, or greater than the second. */ public int compare(DataObject target, DataObject source) { if (target.getDataGraph() == null) throw new IllegalArgumentException("target data-object has no data-graph - " + "data-objects compared for commit operations must have a data graph"); if (source.getDataGraph() == null) throw new IllegalArgumentException("source data-object has no data-graph - " + "data-objects compared for commit operations must have a data graph"); PlasmaChangeSummary changeSummary = (PlasmaChangeSummary) target.getChangeSummary(); int targetDepth = changeSummary.getPathDepth(target); int sourceDepth = changeSummary.getPathDepth(source); int result = 0; if (changeSummary.isCreated(target)) { if (changeSummary.isCreated(source)) { if (isChild(target, source)) { result = 1; // target is a child, create it's parent first } else if (isChild(source, target)) { result = -1; // source is a child, create it's parent first } else { if (targetDepth > sourceDepth) result = 1; else if (sourceDepth > targetDepth) result = -1; else result = 0; } } else result = -1; } else if (changeSummary.isModified(target)) { if (changeSummary.isCreated(source)) { result = 1; } else if (changeSummary.isModified(source)) { if (targetDepth > sourceDepth) result = 1; else if (sourceDepth > targetDepth) result = -1; else result = 0; } else // deleted result = -1; } else { // deleted if (changeSummary.isDeleted(source)) { if (isChild(target, source)) { result = -1; // target is a child, delete it first } else if (isChild(source, target)) { result = 1; // source is a child, delete it first } else { if (targetDepth > sourceDepth) result = -1; else if (sourceDepth > targetDepth) result = 1; else result = 0; } } else // created or modified result = 1; } return result; } private boolean isChild(DataObject target, DataObject source) { return hasChildProperty(target, source); } private boolean hasChildLink(DataObject target, DataObject source) { if (log.isDebugEnabled()) log.debug("comparing " + target.getType().getName() + "/" + source.getType().getName()); // look at properties in target, check if linked to source List<ChangeSummary.Setting> settings = target.getDataGraph().getChangeSummary().getOldValues(target); for (ChangeSummary.Setting setting : settings) { Property property = setting.getProperty(); if (property.getType().isDataType()) continue; // FIXME - equality method for Type ?? if (!property.getType().getName().equals(source.getType().getName())) continue; if (log.isDebugEnabled()) log.debug("checking property " + target.getType().getName() + "." + property.getName()); if (isLinked(source, setting.getValue())) { // singular property linked to source if (!property.isMany()) { if (log.isDebugEnabled()) log.debug("found child data link " + target.getType().getName() + "." + property.getName() + "->" + source.getType().getName()); if (target.getType().getName().equals(source.getType().getName())) throw new IllegalStateException("potential circular reference"); return true; } } } return false; } private boolean hasChildProperty(DataObject target, DataObject source) { if (log.isDebugEnabled()) log.debug("comparing " + target.getType().getName() + "/" + source.getType().getName()); for (Property p : target.getType().getDeclaredProperties()) { Property property = p; // so we can see it in Eclipse debugger if (property.getType().isDataType()) continue; if (!property.getType().getName().equals(source.getType().getName())) continue; // singular property which could be linked in the data-store but // we have just not returned this property in a query if (!property.isMany()) { if (target.getType().getName().equals(source.getType().getName())) throw new IllegalStateException("potential circular reference"); if (log.isDebugEnabled()) log.debug("found child link property " + target.getType().getName() + "." + property.getName() + "->" + source.getType().getName()); return true; } } return false; } private boolean isLinked(DataObject other, Object value) { if (value instanceof List) { List<DataObject> list = (List<DataObject>) value; for (DataObject dataObject : list) { PlasmaNode dataNode = (PlasmaNode) dataObject; if (dataNode.getUUIDAsString().equals(((PlasmaNode) other).getUUIDAsString())) { return true; } } } else { DataObject dataObject = (DataObject) value; PlasmaNode dataNode = (PlasmaNode) dataObject; if (dataNode.getUUIDAsString().equals(((PlasmaNode) other).getUUIDAsString())) { return true; } } return false; } }