    001    //$HeadURL: https://svn.wald.intevation.org/svn/deegree/base/branches/2.4_testing/src/org/deegree/model/feature/XLinkedFeatureProperty.java $
    002    /*----------------------------------------------------------------------------
    003     This file is part of deegree, http://deegree.org/
    004     Copyright (C) 2001-2009 by:
    005       Department of Geography, University of Bonn
    006     and
    007       lat/lon GmbH
    008
    009     This library is free software; you can redistribute it and/or modify it under
    010     the terms of the GNU Lesser General Public License as published by the Free
    011     Software Foundation; either version 2.1 of the License, or (at your option)
    012     any later version.
    013     This library is distributed in the hope that it will be useful, but WITHOUT
    014     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    015     FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
    016     details.
    017     You should have received a copy of the GNU Lesser General Public License
    018     along with this library; if not, write to the Free Software Foundation, Inc.,
    019     59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
    020
    021     Contact information:
    022
    023     lat/lon GmbH
    024     Aennchenstr. 19, 53177 Bonn
    025     Germany
    026     http://lat-lon.de/
    027
    028     Department of Geography, University of Bonn
    029     Prof. Dr. Klaus Greve
    030     Postfach 1147, 53001 Bonn
    031     Germany
    032     http://www.geographie.uni-bonn.de/deegree/
    033
    034     e-mail: info@deegree.org
    035    ----------------------------------------------------------------------------*/
    036    package org.deegree.model.feature;
    037
    038    import org.deegree.datatypes.QualifiedName;
    039
    040    /**
    041     * Feature property instance that does not specify it's content inline, but references a feature
    042     * instance via an XLink.
    043     *
    044     * @author <a href="mailto:schneider@lat-lon.de">Markus Schneider </a>
    045     * @author last edited by: $Author: mschneider $
    046     *
    047     * @version $Revision: 18195 $, $Date: 2009-06-18 17:55:39 +0200 (Do, 18. Jun 2009) $
    048     */
    049    public class XLinkedFeatureProperty implements FeatureProperty {
    050
    051        private QualifiedName name;
    052
    053        private String targetFeatureId;
    054
    055        private Feature targetFeature;
    056
    057        /**
    058         * Creates a new instance of <code>XLinkedFeatureProperty</code> from the given parameters.
    059         * <p>
    060         * NOTE: After creating, this property has no value. The reference to the target feature has to
    061         * be resolved first by calling #setValue(java.lang.Object).
    062         *
    063         * @see #setValue(java.lang.Object)
    064         *
    065         * @param name
    066         *            feature name
    067         * @param targetFeatureId
    068         *            id of the feature that this property contains
    069         */
    070        public XLinkedFeatureProperty( QualifiedName name, String targetFeatureId ) {
    071            this.name = name;
    072            this.targetFeatureId = targetFeatureId;
    073        }
    074
    075        /**
    076         * Returns the name of the property.
    077         *
    078         * @return the name of the property.
    079         */
    080        public QualifiedName getName() {
    081            return this.name;
    082        }
    083
    084        /**
    085         * Returns the value of the property.
    086         *
    087         * @return the value of the property.
    088         */
    089        public Object getValue() {
    090            checkResolved();
    091            return this.targetFeature;
    092        }
    093
    094        /**
    095         * Returns the value of the property.
    096         *
    097         * @return the value of the property.
    098         */
    099        public Object getValue( Object defaultValue ) {
    100            checkResolved();
    101            if ( this.targetFeature == null ) {
    102                return defaultValue;
    103            }
    104            return this.targetFeature;
    105        }
    106
    107        /**
    108         * Sets the target feature instance that this feature property refers to.
    109         *
    110         * @param value
    111         *            feature instance that this feature property refers to
    112         * @throws RuntimeException
    113         *             if the reference has already been resolved
    114         */
    115        public void setValue( Object value ) {
    116            if ( this.targetFeature != null ) {
    117                String msg = Messages.format( "ERROR_REFERENCE_ALREADY_RESOLVED", this.targetFeatureId );
    118                throw new RuntimeException( msg );
    119            }
    120            this.targetFeature = (Feature) value;
    121        }
    122
    123        /*
    124         * (non-Javadoc)
    125         *
    126         * @see org.deegree.model.feature.FeatureProperty#getOwner()
    127         */
    128        public Feature getOwner() {
    129            return null;
    130        }
    131
    132        /**
    133         * Returns the feature id of the target feature.
    134         *
    135         * @return the feature id of the target feature.
    136         */
    137        public String getTargetFeatureId() {
    138            return this.targetFeatureId;
    139        }
    140
    141        /**
    142         * Ensures that the reference to the target feature has been resolved.
    143         *
    144         * @throws RuntimeException
    145         *             if the reference has not been resolved
    146         */
    147        private void checkResolved() {
    148            if ( this.targetFeature == null ) {
    149                String msg = Messages.format( "ERROR_XLINK_NOT_RESOLVED", this.targetFeatureId );
    150                throw new RuntimeException( msg );
    151            }
    152        }
    153    }