001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.data.osm.visitor;
003
004import java.util.HashMap;
005import java.util.List;
006import java.util.Map;
007import java.util.stream.Collectors;
008
009import org.openstreetmap.josm.data.osm.DataSet;
010import org.openstreetmap.josm.data.osm.Node;
011import org.openstreetmap.josm.data.osm.NodeData;
012import org.openstreetmap.josm.data.osm.OsmPrimitive;
013import org.openstreetmap.josm.data.osm.PrimitiveData;
014import org.openstreetmap.josm.data.osm.Relation;
015import org.openstreetmap.josm.data.osm.RelationData;
016import org.openstreetmap.josm.data.osm.RelationMember;
017import org.openstreetmap.josm.data.osm.RelationMemberData;
018import org.openstreetmap.josm.data.osm.Way;
019import org.openstreetmap.josm.data.osm.WayData;
020import org.openstreetmap.josm.tools.CheckParameterUtil;
021import org.openstreetmap.josm.tools.Utils;
022
023/**
024 * MergeSourceBuildingVisitor helps to build the "hull" of a collection of {@link OsmPrimitive}s
025 * which shall be merged into another layer. The "hull" is slightly bigger than the original
026 * collection. It includes, for instance the nodes of a way in the original collection even though
027 * these nodes might not be present explicitly in the original collection. The "hull" also includes
028 * incomplete {@link OsmPrimitive}s which are referred to by relations in the original collection. And
029 * it turns {@link OsmPrimitive} referred to by {@link Relation}s in the original collection into
030 * incomplete {@link OsmPrimitive}s in the "hull", if they are not themselves present in the original collection.
031 * @since 1891
032 */
033public class MergeSourceBuildingVisitor implements OsmPrimitiveVisitor {
034    private final DataSet selectionBase;
035    private final DataSet hull;
036    private final Map<OsmPrimitive, PrimitiveData> mappedPrimitives;
037
038    /**
039     * Creates the visitor. The visitor starts to build the "hull" from
040     * the currently selected primitives in the dataset <code>selectionBase</code>,
041     * i.e. from {@link DataSet#getSelected()}.
042     *
043     * @param selectionBase the dataset. Must not be null.
044     * @throws IllegalArgumentException if selectionBase is null
045     */
046    public MergeSourceBuildingVisitor(DataSet selectionBase) {
047        CheckParameterUtil.ensureParameterNotNull(selectionBase, "selectionBase");
048        this.selectionBase = selectionBase;
049        this.hull = new DataSet();
050        this.mappedPrimitives = new HashMap<>();
051    }
052
053    protected boolean isInSelectionBase(OsmPrimitive primitive) {
054        return selectionBase.getAllSelected().contains(primitive);
055    }
056
057    protected boolean isAlreadyRemembered(OsmPrimitive primitive) {
058        return mappedPrimitives.containsKey(primitive);
059    }
060
061    /**
062     * Remembers a node in the "hull"
063     *
064     * @param n the node
065     */
066    protected void rememberNode(Node n) {
067        if (isAlreadyRemembered(n))
068            return;
069        mappedPrimitives.put(n, n.save());
070    }
071
072    /**
073     * remembers a way in the hull
074     *
075     * @param w the way
076     */
077    protected void rememberWay(Way w) {
078        if (isAlreadyRemembered(w))
079            return;
080        WayData clone = w.save();
081        List<Long> newNodes = Utils.transform(w.getNodes(), n -> mappedPrimitives.get(n).getUniqueId());
082        clone.setNodeIds(newNodes);
083        mappedPrimitives.put(w, clone);
084    }
085
086    /**
087     * Remembers a relation in the hull
088     *
089     * @param r the relation
090     */
091    protected void rememberRelation(Relation r) {
092        RelationData clone;
093        if (isAlreadyRemembered(r)) {
094            clone = (RelationData) mappedPrimitives.get(r);
095        } else {
096            clone = r.save();
097            mappedPrimitives.put(r, clone);
098        }
099
100        clone.setMembers(r.getMembers().stream()
101                .map(m -> new RelationMemberData(m.getRole(), mappedPrimitives.get(m.getMember())))
102                .collect(Collectors.toList()));
103    }
104
105    protected void rememberRelationPartial(Relation r) {
106        if (isAlreadyRemembered(r))
107            return;
108        RelationData clone = r.save();
109        clone.getMembers().clear();
110        mappedPrimitives.put(r, clone);
111    }
112
113    protected void rememberIncomplete(OsmPrimitive primitive) {
114        if (isAlreadyRemembered(primitive))
115            return;
116        PrimitiveData clone = primitive.save();
117        clone.setIncomplete(true);
118        mappedPrimitives.put(primitive, clone);
119    }
120
121    @Override
122    public void visit(Node n) {
123        rememberNode(n);
124    }
125
126    @Override
127    public void visit(Way w) {
128        // remember all nodes this way refers to ...
129        for (Node n: w.getNodes()) {
130            n.accept(this);
131        }
132        // ... and the way itself
133        rememberWay(w);
134    }
135
136    @Override
137    public void visit(Relation r) {
138        // first, remember all primitives members refer to (only if necessary, see below)
139        rememberRelationPartial(r);
140        for (RelationMember member: r.getMembers()) {
141            if (isAlreadyRemembered(member.getMember())) {
142                // referred primitive already remembered
143                continue;
144            }
145            if (isInSelectionBase(member.getMember()) || member.getMember().isNew()) {
146                member.getMember().accept(this);
147            } else {
148                rememberIncomplete(member.getMember());
149            }
150        }
151        rememberRelation(r);
152    }
153
154    protected void buildHull() {
155        // Create all primitives first
156        for (PrimitiveData primitive: mappedPrimitives.values()) {
157            OsmPrimitive newPrimitive = hull.getPrimitiveById(primitive);
158            boolean created = newPrimitive == null;
159            if (created) {
160                newPrimitive = primitive.getType().newInstance(primitive.getUniqueId(), true);
161            }
162            if (newPrimitive instanceof Node && !primitive.isIncomplete()) {
163                newPrimitive.load(primitive);
164            }
165            if (created) {
166                hull.addPrimitive(newPrimitive);
167            }
168        }
169        // Then ways and relations
170        for (PrimitiveData primitive : mappedPrimitives.values()) {
171            if (!(primitive instanceof NodeData) && !primitive.isIncomplete()) {
172                hull.getPrimitiveById(primitive).load(primitive);
173            }
174        }
175    }
176
177    /**
178     * Builds and returns the "hull".
179     * @return the "hull" data set
180     */
181    public DataSet build() {
182        for (OsmPrimitive primitive: selectionBase.getAllSelected()) {
183            primitive.accept(this);
184        }
185        buildHull();
186        return hull;
187    }
188}