mvt layer性能优化

Author: codingmiao

giscat-vector/giscat-vector-mvt/src/main/java/org/wowtools/giscat/vector/mvt/MvtBuilder.java

@@ -76,6 +76,28 @@ public MvtBuilder(byte z, int x, int y, int extent, int clipBuffer, @NotNull Geo
 
     }
 
+    /**
+     * 新建一个图层，按simplifyDistance的值简化geometry
+     *
+     * @param layerName        图层名 本方法没有对图层名进行唯一校验，故若图层已存在，则原图层会被覆盖
+     * @param simplifyDistance 对geometry进行简化的长度,单位是瓦片像素，取值范围[0,extent+clipBuffer]，为0时表示不做简化
+     * @return MvtLayer
+     */
+    public MvtLayer createLayer(String layerName, int simplifyDistance) {
+        MvtLayer layer = new MvtLayer(this, simplifyDistance);
+        layers.put(layerName, layer);
+        return layer;
+    }
+    /**
+     * 新建一个图层，不对geometry进行简化
+     *
+     * @param layerName 图层名 本方法没有对图层名进行唯一校验，故若图层已存在，则原图层会被覆盖
+     * @return MvtLayer
+     */
+    public MvtLayer createLayer(String layerName) {
+        return createLayer(layerName, 0);
+    }
+
     /**
      * 新建或获取一个图层，按simplifyDistance的值简化geometry
      *
@@ -88,9 +110,7 @@ public MvtBuilder(byte z, int x, int y, int extent, int clipBuffer, @NotNull Geo
         if (layer != null) {
             return layer;
         }
-        layer = new MvtLayer(this, simplifyDistance);
-        layers.put(layerName, layer);
-        return layer;
+        return createLayer(layerName, simplifyDistance);
     }
 
     /**
@@ -104,9 +124,7 @@ public MvtBuilder(byte z, int x, int y, int extent, int clipBuffer, @NotNull Geo
         if (layer != null) {
             return layer;
         }
-        layer = new MvtLayer(this, 0);
-        layers.put(layerName, layer);
-        return layer;
+        return createLayer(layerName, 0);
     }
 
 

giscat-vector/giscat-vector-mvt/src/main/java/org/wowtools/giscat/vector/mvt/MvtLayer.java

@@ -25,8 +25,8 @@
 import org.locationtech.jts.geom.GeometryCollection;
 import org.locationtech.jts.geom.TopologyException;
 import org.locationtech.jts.simplify.TopologyPreservingSimplifier;
-import org.wowtools.giscat.vector.util.analyse.Bbox;
 import org.wowtools.giscat.vector.pojo.Feature;
+import org.wowtools.giscat.vector.util.analyse.Bbox;
 
 import java.util.*;
 
@@ -38,7 +38,7 @@
  */
 public final class MvtLayer {
 
-    protected final List<MvtFeature> features = new ArrayList<>();
+    protected final List<MvtFeature> features = new LinkedList<>();
 
     private final Map<String, Integer> keys = new LinkedHashMap<>();
     private final Map<Object, Integer> values = new LinkedHashMap<>();
@@ -145,16 +145,16 @@ private ArrayList<Integer> tags(@Nullable Map<String, ?> attributes) {
         return keys.computeIfAbsent(key, k -> keys.size());
     }
 
-    protected @NotNull List<String> keys() {
-        return new ArrayList<>(keys.keySet());
+    protected @NotNull Set<String> keys() {
+        return keys.keySet();
     }
 
     private @NotNull Integer value(Object value) {
         return values.computeIfAbsent(value, k -> values.size());
     }
 
-    protected List<Object> values() {
-        return List.copyOf(values.keySet());
+    protected Set<Object> values() {
+        return values.keySet();
     }