Merge pull request #225 from GoogleCloudPlatform/ds-geo

Add AE Datastore geo query sample.
GoogleCloudPlatform · May 2, 2016 · aad960b · aad960b
2 parents 87ee84d + 2d79581
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diff --git a/appengine/datastore/geo/pom.xml b/appengine/datastore/geo/pom.xml
@@ -0,0 +1,94 @@
+<!--
+  Copyright 2016 Google Inc. All Rights Reserved.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+<project>
+  <modelVersion>4.0.0</modelVersion>
+  <packaging>war</packaging>
+  <version>1.0-SNAPSHOT</version>
+  <groupId>com.example.appengine</groupId>
+  <artifactId>appengine-datastore-geo</artifactId>
+
+  <parent>
+    <groupId>com.google.cloud</groupId>
+    <artifactId>doc-samples</artifactId>
+    <version>1.0.0</version>
+    <relativePath>../../..</relativePath>
+  </parent>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.google.appengine</groupId>
+      <artifactId>appengine-api-1.0-sdk</artifactId>
+      <version>${appengine.sdk.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>javax.servlet</groupId>
+      <artifactId>servlet-api</artifactId>
+      <type>jar</type>
+      <scope>provided</scope>
+    </dependency>
+
+    <!-- Test Dependencies -->
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.10</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-all</artifactId>
+      <version>1.10.19</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.google.appengine</groupId>
+      <artifactId>appengine-testing</artifactId>
+      <version>${appengine.sdk.version}</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.google.appengine</groupId>
+      <artifactId>appengine-api-stubs</artifactId>
+      <version>${appengine.sdk.version}</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.google.appengine</groupId>
+      <artifactId>appengine-tools-sdk</artifactId>
+      <version>${appengine.sdk.version}</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>com.google.truth</groupId>
+      <artifactId>truth</artifactId>
+      <version>0.28</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <!-- for hot reload of the web application -->
+    <outputDirectory>${project.build.directory}/${project.build.finalName}/WEB-INF/classes</outputDirectory>
+    <plugins>
+      <!-- Parent POM defines ${appengine.sdk.version} (updates frequently). -->
+      <plugin>
+        <groupId>com.google.appengine</groupId>
+        <artifactId>appengine-maven-plugin</artifactId>
+        <version>${appengine.sdk.version}</version>
+      </plugin>
+    </plugins>
+  </build>
+</project>
diff --git a/appengine/datastore/geo/src/main/java/com/example/appengine/GeoServlet.java b/appengine/datastore/geo/src/main/java/com/example/appengine/GeoServlet.java
@@ -0,0 +1,175 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.appengine;
+
+import com.google.appengine.api.datastore.DatastoreService;
+import com.google.appengine.api.datastore.DatastoreServiceFactory;
+import com.google.appengine.api.datastore.Entity;
+import com.google.appengine.api.datastore.FetchOptions;
+import com.google.appengine.api.datastore.GeoPt;
+import com.google.appengine.api.datastore.Query;
+import com.google.appengine.api.datastore.Query.CompositeFilterOperator;
+import com.google.appengine.api.datastore.Query.Filter;
+import com.google.appengine.api.datastore.Query.FilterOperator;
+import com.google.appengine.api.datastore.Query.FilterPredicate;
+import com.google.appengine.api.datastore.Query.GeoRegion.Circle;
+import com.google.appengine.api.datastore.Query.GeoRegion.Rectangle;
+import com.google.appengine.api.datastore.Query.StContainsFilter;
+
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.util.List;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * A servlet to demonstrate the use of Cloud Datastore geospatial queries.
+ */
+public class GeoServlet extends HttpServlet {
+  static final String BRAND_PROPERTY = "brand";
+  static final String LOCATION_PROPERTY = "location";
+
+  static final String BRAND_PARAMETER = "brand";
+  static final String LATITUDE_PARAMETER = "lat";
+  static final String LONGITUDE_PARAMETER = "lon";
+  static final String RADIUS_PARAMETER = "r";
+
+  static final String BRAND_DEFAULT = "Ocean Ave Shell";
+  static final String LATITUDE_DEFAULT = "37.7895873";
+  static final String LONGITUDE_DEFAULT = "-122.3917317";
+  static final String RADIUS_DEFAULT = "1000.0";
+
+  // Number of meters (approximately) in 1 degree of latitude.
+  // http://gis.stackexchange.com/a/2964
+  private static final double DEGREE_METERS = 111111.0;
+
+  private final DatastoreService datastore;
+
+  public GeoServlet() {
+    datastore = DatastoreServiceFactory.getDatastoreService();
+  }
+
+  private static String getParameterOrDefault(
+      HttpServletRequest req, String parameter, String defaultValue) {
+    String value = req.getParameter(parameter);
+    if (value == null || value.isEmpty()) {
+      value = defaultValue;
+    }
+    return value;
+  }
+
+  private static GeoPt getOffsetPoint(
+      GeoPt original, double latOffsetMeters, double lonOffsetMeters) {
+    // Approximate the number of degrees to offset by meters.
+    // http://gis.stackexchange.com/a/2964
+    // How long (approximately) is one degree of longitude?
+    double lonDegreeMeters = DEGREE_METERS * Math.cos(original.getLatitude());
+    return new GeoPt(
+        (float) (original.getLatitude() + latOffsetMeters / DEGREE_METERS),
+        // This may cause errors if given points near the north or south pole.
+        (float) (original.getLongitude() + lonOffsetMeters / lonDegreeMeters));
+  }
+
+  @Override
+  public void doGet(HttpServletRequest req, HttpServletResponse resp)
+      throws IOException, ServletException {
+    resp.setContentType("text/plain");
+    resp.setCharacterEncoding("UTF-8");
+    PrintWriter out = resp.getWriter();
+
+    String brand = getParameterOrDefault(req, BRAND_PARAMETER, BRAND_DEFAULT);
+    String latStr = getParameterOrDefault(req, LATITUDE_PARAMETER, LATITUDE_DEFAULT);
+    String lonStr = getParameterOrDefault(req, LONGITUDE_PARAMETER, LONGITUDE_DEFAULT);
+    String radiusStr = getParameterOrDefault(req, RADIUS_PARAMETER, RADIUS_DEFAULT);
+
+    float latitude;
+    float longitude;
+    double r;
+    try {
+      latitude = Float.parseFloat(latStr);
+      longitude = Float.parseFloat(lonStr);
+      r = Double.parseDouble(radiusStr);
+    } catch (IllegalArgumentException e) {
+      resp.sendError(
+          HttpServletResponse.SC_BAD_REQUEST, String.format("Got bad value: %s", e.getMessage()));
+      return;
+    }
+
+    // Get lat/lon for rectangle.
+    GeoPt c = new GeoPt(latitude, longitude);
+    GeoPt ne = getOffsetPoint(c, r, r);
+    float neLat = ne.getLatitude();
+    float neLon = ne.getLongitude();
+    GeoPt sw = getOffsetPoint(c, -1 * r, -1 * r);
+    float swLat = sw.getLatitude();
+    float swLon = sw.getLongitude();
+
+    // [START geospatial_stcontainsfilter_examples]
+    // Testing for containment within a circle
+    GeoPt center = new GeoPt(latitude, longitude);
+    double radius = r; // Value is in meters.
+    Filter f1 = new StContainsFilter("location", new Circle(center, radius));
+    Query q1 = new Query("GasStation").setFilter(f1);
+
+    // Testing for containment within a rectangle
+    GeoPt southwest = new GeoPt(swLat, swLon);
+    GeoPt northeast = new GeoPt(neLat, neLon);
+    Filter f2 = new StContainsFilter("location", new Rectangle(southwest, northeast));
+    Query q2 = new Query("GasStation").setFilter(f2);
+    // [END geospatial_stcontainsfilter_examples]
+
+    List<Entity> circleResults = datastore.prepare(q1).asList(FetchOptions.Builder.withDefaults());
+    out.printf("Got %d stations in %f meter radius circle.\n", circleResults.size(), radius);
+    printStations(out, circleResults);
+    out.println();
+
+    List<Entity> rectResults = datastore.prepare(q2).asList(FetchOptions.Builder.withDefaults());
+    out.printf("Got %d stations in rectangle.\n", rectResults.size());
+    printStations(out, rectResults);
+    out.println();
+
+    List<Entity> brandResults = getStationsWithBrand(center, radius, brand);
+    out.printf("Got %d stations in circle with brand %s.\n", brandResults.size(), brand);
+    printStations(out, brandResults);
+    out.println();
+  }
+
+  private void printStations(PrintWriter out, List<Entity> stations) {
+    for (Entity station : stations) {
+      GeoPt location = (GeoPt) station.getProperty(LOCATION_PROPERTY);
+      out.printf(
+          "%s: @%f, %f\n",
+          (String) station.getProperty(BRAND_PROPERTY),
+          location.getLatitude(),
+          location.getLongitude());
+    }
+  }
+
+  private List<Entity> getStationsWithBrand(GeoPt center, double radius, String value) {
+    // [START geospatial_containment_and_equality_combination]
+    Filter f =
+        CompositeFilterOperator.and(
+            new StContainsFilter("location", new Circle(center, radius)),
+            new FilterPredicate("brand", FilterOperator.EQUAL, value));
+    // [END geospatial_containment_and_equality_combination]
+    Query q = new Query("GasStation").setFilter(f);
+    return datastore.prepare(q).asList(FetchOptions.Builder.withDefaults());
+  }
+}
diff --git a/appengine/datastore/geo/src/main/java/com/example/appengine/StartupServlet.java b/appengine/datastore/geo/src/main/java/com/example/appengine/StartupServlet.java
@@ -0,0 +1,80 @@
+/*
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.appengine;
+
+import com.google.appengine.api.datastore.DatastoreService;
+import com.google.appengine.api.datastore.DatastoreServiceFactory;
+import com.google.appengine.api.datastore.Entity;
+import com.google.appengine.api.datastore.EntityNotFoundException;
+import com.google.appengine.api.datastore.GeoPt;
+import com.google.appengine.api.datastore.Key;
+import com.google.appengine.api.datastore.KeyFactory;
+
+import java.io.IOException;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * A startup handler to populate the datastore with example entities.
+ */
+public class StartupServlet extends HttpServlet {
+  static final String IS_POPULATED_ENTITY = "IsPopulated";
+  static final String IS_POPULATED_KEY_NAME = "is-populated";
+
+  @Override
+  protected void doGet(HttpServletRequest req, HttpServletResponse resp)
+      throws ServletException, IOException {
+    resp.setContentType("text/plain");
+    DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
+
+    Key isPopulatedKey = KeyFactory.createKey(IS_POPULATED_ENTITY, IS_POPULATED_KEY_NAME);
+    boolean isAlreadyPopulated;
+    try {
+      datastore.get(isPopulatedKey);
+      isAlreadyPopulated = true;
+    } catch (EntityNotFoundException expected) {
+      isAlreadyPopulated = false;
+    }
+    if (isAlreadyPopulated) {
+      resp.getWriter().println("ok");
+      return;
+    }
+
+    // [START create_entity_with_geopt_property]
+    Entity station = new Entity("GasStation");
+    station.setProperty("brand", "Ocean Ave Shell");
+    station.setProperty("location", new GeoPt(37.7913156f, -122.3926051f));
+    datastore.put(station);
+    // [END create_entity_with_geopt_property]
+
+    station = new Entity("GasStation");
+    station.setProperty("brand", "Charge Point Charging Station");
+    station.setProperty("location", new GeoPt(37.7909778f, -122.3929963f));
+    datastore.put(station);
+
+    station = new Entity("GasStation");
+    station.setProperty("brand", "76");
+    station.setProperty("location", new GeoPt(37.7860533f, -122.3940325f));
+    datastore.put(station);
+
+    datastore.put(new Entity(isPopulatedKey));
+    resp.getWriter().println("ok");
+  }
+}
diff --git a/appengine/datastore/geo/src/main/webapp/WEB-INF/appengine-web.xml b/appengine/datastore/geo/src/main/webapp/WEB-INF/appengine-web.xml
@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright 2016 Google Inc. All Rights Reserved.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+<appengine-web-app xmlns="http://appengine.google.com/ns/1.0">
+  <application>YOUR-PROJECT-ID</application>
+  <version>YOUR-VERSION-ID</version>
+  <threadsafe>true</threadsafe>
+</appengine-web-app>