org.obiba.onyx.core.domain.participant.ParticipantAttributeReader.java Source code

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Here is the source code for org.obiba.onyx.core.domain.participant.ParticipantAttributeReader.java

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/*******************************************************************************
 * Copyright 2008(c) The OBiBa Consortium. All rights reserved.
 * 
 * This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3.0.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************/
package org.obiba.onyx.core.domain.participant;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.LinkedBlockingQueue;

import org.obiba.onyx.wicket.data.DataValidator;
import org.obiba.onyx.wicket.data.validation.converter.DataValidatorConverter;
import org.springframework.core.io.Resource;

import com.thoughtworks.xstream.XStream;

public class ParticipantAttributeReader {
    //
    // Instance Variables
    //

    private XStream xstream = new XStream();

    private Resource[] resources;

    //
    // Constructors
    //

    public ParticipantAttributeReader() {
        // Create an alias for the root node.
        xstream.alias("participantAttributes", List.class);

        // Create an alias for ParticipantAttribute nodes
        xstream.alias("attribute", ParticipantAttribute.class);

        xstream.alias("group", Group.class);

        // Put name in an attribute, instead of an element.
        xstream.useAttributeFor(Group.class, "name");

        // Removes the redundant <participantAttributes> child element from <group>.
        xstream.addImplicitCollection(Group.class, "participantAttributes");

        // Use DataValidatorConverter to allow easier aliases for validator nodes
        xstream.alias("dataValidator", DataValidator.class);
        xstream.useAttributeFor(DataValidator.class, "dataType");
        xstream.registerConverter(new DataValidatorConverter().createAliases(xstream));
    }

    //
    // Methods
    //

    public void setResources(Resource[] resources) {
        this.resources = resources;
    }

    @SuppressWarnings("unchecked")
    public List<ParticipantAttribute> read() throws IOException {
        List<ParticipantElement> participantElements = new ArrayList<ParticipantElement>();

        for (int i = 0; i < this.resources.length; i++) {
            Resource resource = this.resources[i];

            if (resource.exists()) {
                participantElements.addAll((List<ParticipantElement>) xstream.fromXML(resource.getInputStream()));
            }
        }

        return flatten(participantElements);
    }

    /**
     * Flattens a list of attributes and groups of attributes into a list of attributes. Attributes that were children of
     * a group set a member to refer to the {@code Group} object. {@code Group} objects are set to refer to all their
     * child attributes.
     * @param participantElements List of attributes and groups of attributes.
     * @return List of attributes. Attributes that were part of a group will contain a reference to that group.
     */
    private List<ParticipantAttribute> flatten(List<ParticipantElement> participantElements) {

        Group defaultGroup = new Group(Group.DEFAULT_GROUP_NAME);
        List<ParticipantAttribute> attributeList = new ArrayList<ParticipantAttribute>();
        for (ParticipantElement participantElement : participantElements) {
            doFlatten(participantElement, defaultGroup, attributeList);
        }
        return attributeList;
    }

    private void doFlatten(ParticipantElement participantElement, Group group,
            List<ParticipantAttribute> attributeList) {
        if (participantElement instanceof ParticipantAttribute) {
            ParticipantAttribute attribute = (ParticipantAttribute) participantElement;
            attribute.setGroup(group);
            if (group.getName().equals(Group.DEFAULT_GROUP_NAME)) {
                // Add attributes without a group to the default group.
                group.addParticipantAttribute(attribute);
            }
            attributeList.add(attribute);
            return;
        } else if (participantElement instanceof Group) {
            Group childGroup = (Group) participantElement;
            LinkedBlockingQueue<ParticipantAttribute> childElements = new LinkedBlockingQueue<ParticipantAttribute>(
                    childGroup.getParticipantAttributes());
            for (ParticipantElement childElement : childElements) {
                doFlatten(childElement, childGroup, attributeList);
            }
        }
    }

}