1 | // License: GPL. For details, see LICENSE file.
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2 | package org.openstreetmap.josm.io;
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3 |
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4 | import java.io.StringWriter;
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5 | import java.util.HashMap;
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6 | import java.util.Iterator;
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7 | import java.util.Map;
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8 | import java.util.Map.Entry;
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9 |
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10 | import javax.json.Json;
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11 | import javax.json.JsonArrayBuilder;
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12 | import javax.json.JsonObjectBuilder;
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13 | import javax.json.JsonWriter;
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14 | import javax.json.stream.JsonGenerator;
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15 |
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16 | import org.openstreetmap.josm.data.Bounds;
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17 | import org.openstreetmap.josm.data.coor.LatLon;
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18 | import org.openstreetmap.josm.data.osm.DataSet;
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19 | import org.openstreetmap.josm.data.osm.INode;
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20 | import org.openstreetmap.josm.data.osm.IRelation;
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21 | import org.openstreetmap.josm.data.osm.IWay;
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22 | import org.openstreetmap.josm.data.osm.Node;
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23 | import org.openstreetmap.josm.data.osm.OsmPrimitive;
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24 | import org.openstreetmap.josm.data.osm.Way;
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25 | import org.openstreetmap.josm.data.osm.visitor.PrimitiveVisitor;
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26 | import org.openstreetmap.josm.gui.layer.OsmDataLayer;
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27 |
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28 | /**
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29 | * Writes OSM data as a GeoJSON string, using JSR 353: Java API for JSON Processing (JSON-P).
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30 | */
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31 | public class GeoJSONWriter {
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32 |
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33 | private OsmDataLayer layer;
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34 | private static final boolean skipEmptyNodes = true;
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35 |
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36 | /**
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37 | * Constructs a new {@code GeoJSONWriter}.
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38 | * @param layer The OSM data layer to save
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39 | */
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40 | public GeoJSONWriter(OsmDataLayer layer) {
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41 | this.layer = layer;
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42 | }
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43 |
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44 | /**
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45 | * Writes OSM data as a GeoJSON string (prettified).
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46 | * @return The GeoJSON data
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47 | */
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48 | public String write() {
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49 | return write(true);
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50 | }
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51 |
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52 | /**
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53 | * Writes OSM data as a GeoJSON string (prettified or not).
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54 | * @param pretty {@code true} to have pretty output, {@code false} otherwise
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55 | * @return The GeoJSON data
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56 | * @since 6756
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57 | */
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58 | public String write(boolean pretty) {
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59 | StringWriter stringWriter = new StringWriter();
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60 | Map<String, Object> config = new HashMap<>(1);
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61 | config.put(JsonGenerator.PRETTY_PRINTING, pretty);
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62 | try (JsonWriter writer = Json.createWriterFactory(config).createWriter(stringWriter)) {
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63 | JsonObjectBuilder object = Json.createObjectBuilder()
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64 | .add("type", "FeatureCollection")
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65 | .add("generator", "JOSM");
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66 | appendLayerBounds(layer.data, object);
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67 | appendLayerFeatures(layer.data, object);
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68 | writer.writeObject(object.build());
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69 | return stringWriter.toString();
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70 | }
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71 | }
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72 |
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73 | private static class GeometryPrimitiveVisitor implements PrimitiveVisitor {
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74 |
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75 | private final JsonObjectBuilder geomObj;
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76 |
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77 | public GeometryPrimitiveVisitor(JsonObjectBuilder geomObj) {
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78 | this.geomObj = geomObj;
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79 | }
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80 |
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81 | @Override
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82 | public void visit(INode n) {
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83 | geomObj.add("type", "Point");
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84 | LatLon ll = n.getCoor();
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85 | if (ll != null) {
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86 | geomObj.add("coordinates", getCoorArray(n.getCoor()));
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87 | }
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88 | }
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89 |
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90 | @Override
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91 | public void visit(IWay w) {
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92 | geomObj.add("type", "LineString");
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93 | if (w instanceof Way) {
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94 | JsonArrayBuilder array = Json.createArrayBuilder();
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95 | for (Node n : ((Way)w).getNodes()) {
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96 | LatLon ll = n.getCoor();
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97 | if (ll != null) {
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98 | array.add(getCoorArray(ll));
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99 | }
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100 | }
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101 | geomObj.add("coordinates", array);
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102 | }
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103 | }
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104 |
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105 | @Override
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106 | public void visit(IRelation r) {
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107 | }
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108 |
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109 | private JsonArrayBuilder getCoorArray(LatLon c) {
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110 | return Json.createArrayBuilder().add(c.lon()).add(c.lat());
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111 | }
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112 | }
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113 |
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114 | protected static void appendPrimitive(OsmPrimitive p, JsonArrayBuilder array) {
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115 | if (p.isIncomplete()) {
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116 | return;
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117 | } else if (skipEmptyNodes && p instanceof Node && p.getKeys().isEmpty()) {
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118 | return;
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119 | }
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120 |
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121 | // Properties
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122 | final JsonObjectBuilder propObj = Json.createObjectBuilder();
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123 | for (Entry<String, String> t : p.getKeys().entrySet()) {
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124 | propObj.add(t.getKey(), t.getValue());
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125 | }
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126 |
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127 | // Geometry
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128 | final JsonObjectBuilder geomObj = Json.createObjectBuilder();
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129 | p.accept(new GeometryPrimitiveVisitor(geomObj));
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130 |
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131 | // Build primitive JSON object
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132 | array.add(Json.createObjectBuilder()
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133 | .add("type", "Feature")
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134 | .add("properties", propObj)
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135 | .add("geometry", geomObj));
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136 | }
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137 |
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138 | protected static void appendLayerBounds(DataSet ds, JsonObjectBuilder object) {
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139 | if (ds != null) {
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140 | Iterator<Bounds> it = ds.getDataSourceBounds().iterator();
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141 | if (it.hasNext()) {
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142 | Bounds b = new Bounds(it.next());
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143 | while (it.hasNext()) {
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144 | b.extend(it.next());
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145 | }
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146 | appendBounds(b, object);
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147 | }
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148 | }
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149 | }
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150 |
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151 | protected static void appendBounds(Bounds b, JsonObjectBuilder object) {
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152 | if (b != null) {
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153 | object.add("bbox", Json.createArrayBuilder()
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154 | .add(b.getMinLon()).add(b.getMinLat())
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155 | .add(b.getMaxLon()).add(b.getMaxLat()));
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156 | }
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157 | }
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158 |
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159 | protected static void appendLayerFeatures(DataSet ds, JsonObjectBuilder object) {
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160 | JsonArrayBuilder array = Json.createArrayBuilder();
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161 | if (ds != null) {
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162 | for (Node n : ds.getNodes()) {
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163 | appendPrimitive(n, array);
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164 | }
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165 | for (Way w : ds.getWays()) {
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166 | appendPrimitive(w, array);
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167 | }
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168 | }
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169 | object.add("features", array);
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170 | }
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171 | }
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