source: josm/src/org/openstreetmap/josm/gui/layer/DataLayer.java@ 17

package org.openstreetmap.josm.gui.layer;

import java.awt.Graphics;

import org.openstreetmap.josm.data.osm.DataSet;
import org.openstreetmap.josm.data.osm.LineSegment;
import org.openstreetmap.josm.data.osm.Node;
import org.openstreetmap.josm.data.osm.Track;
import org.openstreetmap.josm.gui.MapView;
import org.openstreetmap.josm.gui.engine.Engine;

/**
 * Base class for all layer that depends on some DataSet.
 * The dataset is final and so can not be changed later.
 * 
 * @author imi
 */
public abstract class DataLayer implements Layer {

        /**
         * The dataSet this layer operates on.
         */
        protected final DataSet dataSet;
        /**
         * The engine used to draw the data.
         */
        protected final Engine engine;
        /**
         * The name of this layer.
         */
        private final String name;
        /**
         * The visibility state of the layer.
         */
        private boolean visible = true;

        /**
         * Construct the datalayer and fill the dataset.
         * @param name The name of this layer. Returned by getName.
         */
        public DataLayer(DataSet dataSet, Engine engine, String name) {
                if (dataSet == null || engine == null || name == null)
                        throw new NullPointerException();
                this.name = name;
                this.dataSet = dataSet;
                this.engine = engine;
        }

        /**
         * Paint the dataset using the engine set.
         * @param mv The object that can translate GeoPoints to screen coordinates.
         */
        public void paint(Graphics g, MapView mv) {
                engine.init(g, mv);

                for (Track t : dataSet.tracks())
                        engine.drawTrack(t);
                for (LineSegment ls : dataSet.pendingLineSegments())
                        engine.drawPendingLineSegment(ls);
                for (Node n : dataSet.nodes)
                        engine.drawNode(n);
        }

        /**
         * Return the data set behind this data layer.
         */
        public DataSet getDataSet() {
                return dataSet;
        }

        public String getName() {
                return name;
        }

        public boolean isVisible() {
                return visible;
        }

        public void setVisible(boolean visible) {
                this.visible = visible;
        }
}