How to implement the Set command of Springboot integrated Tile client

set command syntax

SET key id [FIELD name value ...] [EX seconds] [NX|XX] (OBJECT geojson )|(POINT lat lon z)|(BOUNDS minlat minlon maxlat maxlon)|(HASH geohash)|(STRING value)

##set command is equivalent to # in redis The use of the ##hash command is also a combination of key and id, but the difference is that Tile38’s set command can also carry more Other attributes, such as customizing the FIELD field, and setting the EX validity period, etc., then we need to design a useful java api## for this syntax. # so that developers can better use Tile38. Grammar analysis

First of all, according to the grammar provided above, we can divide it into three parts:

1. The first part is the revelation keyword of the command

SET

, we take this keyword as a separate part;

2. The second part is key id [FIELD name value ...] [EX seconds] [NX|XX]

, We take these as parameters;

3. The third part is the final target data object:

(OBJECT geojson)|(POINT lat lon z)|(BOUNDS minlat minlon maxlat maxlon)|(HASH geohash)|(STRING value)

Code design

1. We manage the first part of the command keywords through enumeration:

enum Tile38Command implements ProtocolKeyword {
    SET;
    public final byte[] bytes;
    static final String UNDERSCORE = "_";
    static final String SPACE = " ";
    Tile38Command() {
      String name = StringUtils.replace(this.name(), UNDERSCORE, SPACE);
      this.bytes = name.getBytes(StandardCharsets.US_ASCII);
    }
    @Override
    public byte[] getBytes() {
      return this.bytes;
    }
}

Because the redis client tool needs to encode all commands before sending them, all commands must implement the

ProtocolKeyword

interface. If the starting keyword of the command is two or more words, then we will use underscores to connect them. When converting to bytes, we can use spaces to replace the underscores.

2. We abstract the second part of the command into a specific class and describe it through related fields:

public class SetOpts {
  private String key;
  private String id;
  //字段值必须是双精度浮点型
  private Map<String, Double> fields;
  // 单位秒
  private int ex;
  // 创建方式：
  // NX 不存在的时候创建
  // XX 存在的时候更新
  private NxXx nxXx;
  private SetOpts(Builder builder) {
    this.key = builder.key;
    this.id = builder.id;
    this.fields = builder.fields;
    this.ex = builder.ex;
    this.nxXx = builder.nxXx;
  }
  
  // 把所有的参数按顺序放到列表中
  public List<String> commandLine() {
    List<String> result = new LinkedList<>();
    result.add(this.key);
    result.add(this.id);
    // 添加所有的FIELD
    if (MapUtils.isNotEmpty(this.fields)) {
      for (Map.Entry<String, Double> entry : this.fields.entrySet()) {
        result.add("FIELD");
        result.add(entry.getKey());
        result.add(entry.getValue().toString());
      }
    }
    // 添加`EX`
    if (this.ex >= 0) {
      result.add("EX");
      result.add(String.valueOf(this.ex));
    }
    // 添加NX或XX
    if (Objects.nonNull(this.nxXx)) {
      result.add(this.nxXx.name());
    }
    // 返回结果
    return result;
  }
  
  public enum NxXx {
    NX,
    XX
  }
  // 建造者模式
  public static class Builder {
    private String key;
    private String id;
    //字段值必须是双精度浮点型
    private Map<String, Double> fields;
    // 单位秒
    private int ex = -1;
    // 创建方式：
    // NX 不存在的时候创建
    // XX 存在的时候更新
    private NxXx nxXx;
    public Builder key(String key) {
      this.key = key;
      return this;
    }
    public Builder id(String id) {
      this.id = id;
      return this;
    }
    public Builder field(String field, double value) {
      if (Objects.isNull(this.fields)) {
        this.fields = new LinkedHashMap<>();
      }
      this.fields.put(field, value);
      return this;
    }
    public Builder ex(int seconds) {
      this.ex = seconds;
      return this;
    }
    public Builder nxXx(NxXx nxXx) {
      this.nxXx = nxXx;
      return this;
    }
    public SetOpts build() throws AwesomeException {
      if (StringUtils.isEmpty(this.key)) {
        throw new AwesomeException(500, "key is empty");
      }
      if (StringUtils.isEmpty(this.id)) {
        throw new AwesomeException(500, "id is empty");
      }
      // 创建SetOpts对象
      return new SetOpts(this);
    }
  }
}

We above use the builder's design mode to put all the parameters All are converted into the SetOpts class, and developers can flexibly control the parameters in the command through the construction of SetOpts objects.

3. We need to convert the different data objects in the third part into different types:

POINT data type

The key field of Point is longitude and latitude, in addition In addition, there is an additional field

z

, which is used to store additional business parameters and can be empty.

public class Point extends Element implements Serializable {
  // 经度
  private double lng;
  // 维度
  private double lat;
  // 额外的数据
  private double z;
  public Point(double lng, double lat, double z) {
    this.lat = lat;
    this.lng = lng;
    this.z = z;
  }
  public Point(double lng, double lat) {
    this(lng, lat, Integer.MIN_VALUE);
  }
  @Override
  public List<String> commandArgs() {
    List<String> result = new LinkedList<>();
    result.add("POINT");
    result.add(String.valueOf(this.lng));
    result.add(String.valueOf(this.lat));
    if (this.z != Integer.MIN_VALUE) {
      result.add(String.valueOf(this.z));
    }
    return result;
  }
}

BOUNDS data type

BOUNDS is a rectangle, and its key fields are the lower left corner and upper right corner. We use coordinate1 and coordinate2 to represent the lower left corner and upper right corner;

@AllArgsConstructor
public class Bounds extends Element {
  private double[] coordinate1;
  private double[] coordinate2;
  @Override
  public List<String> commandArgs() {
    List<String> result = new LinkedList<>();
    result.add("BOUNDS");
    result.add(String.valueOf(coordinate1[0]));
    result.add(String.valueOf(coordinate1[1]));
    result.add(String.valueOf(coordinate2[0]));
    result.add(String.valueOf(coordinate2[1]));
    return result;
  }
}

HASH and STRING data types

HASH and STRING are actually a separate string, but we still encapsulate it for developers to use;

@AllArgsConstructor
public class Geohash extends Element {
  private String hash;
  @Override
  public List<String> commandArgs() {
    List<String> result = new LinkedList<>();
    result.add("HASH");
    result.add(this.hash);
    return result;
  }
}
@AllArgsConstructor
public class RawString extends Element {
  private String raw;
  @Override
  public List<String> commandArgs() {
    List<String> result = new LinkedList<>();
    result.add("STRING");
    result.add(this.raw);
    return result;
  }
}

OBJECT data Type

OBJECT is actually GeoJSON data. This type of data is a bit more complicated. There are six types in total. Friends who want to know more can see here geojson.org/

Point,
LineString,
Polygon,
MultiPoint,
MultiLineString,
MultiPolygon

In order for developers to To better use these six types, we also use the builder pattern to design the GeoJSON data type:

@Data
public class GeoJson {
  public static class Builder {
    public Point.Builder point() {
      return new Point.Builder();
    }
    public MultiPoint.Builder multPoint() {
      return new MultiPoint.Builder();
    }
    public LineString.Builder lineString() {
      return new LineString.Builder();
    }
    public MultiLineString.Builder multiLineString() {
      return new MultiLineString.Builder();
    }
    public Polygon.Builder polygon() {
      return new Polygon.Builder();
    }
    public MultiPolygon.Builder multiPolygon() {
      return new MultiPolygon.Builder();
    }
  }
}

We now create multiple methods in a large class, and each method puts the builder of the corresponding type Created, in this case, it is equivalent to six ways of creating objects in this class, and each builder is only responsible for building the corresponding object.

The following are the codes of the six builders. Each object is constructed based on the most basic BaseGeoJson. The public field type and additional meta fields are extracted from BaseGeoJson. The difference between each type lies in the coordinates. The number and level of points are different, so according to the characteristics of each type, the code design is as follows:

// Point类型
  public static class Point extends BaseGeoJson {
    // 坐标点
    private double[] coordinates;
    Point(Builder builder) {
      super(builder);
      this.type = GeoJsonType.Point;
      this.coordinates = builder.coordinates;
    }
    @Override
    protected Object coordinates() {
      return this.coordinates;
    }
    public static class Builder extends BaseGeoJson.Builder {
      private double[] coordinates;
      public Builder coordinate(double lon, double lat) {
        coordinates = new double[]{lat, lon};
        return this;
      }
      public Point build() {
        return new Point(this);
      }
    }
  }
// MultiPoint类型
  public static class MultiPoint extends BaseGeoJson {
    private double[][] coordinates;
    MultiPoint(Builder builder) {
      super(builder);
      this.type = GeoJsonType.MultiPoint;
      this.coordinates = builder.convert2Array();
    }
    @Override
    protected Object coordinates() {
      return this.coordinates;
    }
    public static class Builder extends BaseGeoJson.Builder {
      private List<Coordinate> coordinates;
      public Builder coordinate(double lon, double lat) {
        if (CollectionUtils.isEmpty(this.coordinates)) {
          this.coordinates = new LinkedList<>();
        }
        this.coordinates.add(new Coordinate(lat, lon));
        return this;
      }
      protected double[][] convert2Array() {
        int length = this.coordinates.size();
        double[][] result = new double[length][];
        for (int i = 0; i < length; i++) {
          result[i] = this.coordinates.get(i).convertToArray();
        }
        return result;
      }
      @Override
      public MultiPoint build() {
        return new MultiPoint(this);
      }
    }
  }
// LineString类型
  public static class LineString extends MultiPoint {
    private double[][] coordinates;
    LineString(Builder builder) {
      super(builder);
      this.type = GeoJsonType.LineString;
    }
    public static class Builder extends MultiPoint.Builder {
      @Override
      public LineString build() {
        return new LineString(this);
      }
    }
  }
// MultiLineString类型
  public static class MultiLineString extends BaseGeoJson {
    private double[][][] coordinates;
    MultiLineString(Builder builder) {
      super(builder);
      this.type = GeoJsonType.MultiLineString;
      this.coordinates = builder.convertToArray();
    }
    @Override
    protected Object coordinates() {
      return this.coordinates;
    }
    public static class Builder extends BaseGeoJson.Builder {
      private List<Line> lines = new LinkedList<>();
      public Line line() {
        return new Line(this);
      }
      void addLine(Line line) {
        lines.add(line);
      }
      double[][][] convertToArray() {
        int length = this.lines.size();
        double[][][] result = new double[length][][];
        for (int i = 0; i < length; i++) {
          Line line = this.lines.get(i);
          result[i] = line.convert2Array();
        }
        return result;
      }
      @Override
      public BaseGeoJson build() {
        return new MultiLineString(this);
      }
    }
    static class Line {
      private List<Coordinate> coordinates;
      private Builder builder;
      Line(Builder builder) {
        this.builder = builder;
        this.builder.addLine(this);
      }
      private double[][] convert2Array() {
        int length = this.coordinates.size();
        double[][] result = new double[length][];
        for (int i = 0; i < length; i++) {
          result[i] = this.coordinates.get(i).convertToArray();
        }
        return result;
      }
      public Line coordinate(double lon, double lat) {
        if (CollectionUtils.isEmpty(this.coordinates)) {
          this.coordinates = new LinkedList<>();
        }
        this.coordinates.add(new Coordinate(lat, lon));
        return this;
      }
      public Line nextLine() {
        return new Line(this.builder);
      }
      public Builder end() {
        return this.builder;
      }
    }
  }
// Polygon类型
  public static class Polygon extends MultiPoint {
    private double[][][] coordinates;
    Polygon(Builder builder) {
      super(builder);
      this.type = GeoJsonType.Polygon;
      this.coordinates = new double[][][]{builder.convert2Array()};
    }
    public static class Builder extends MultiPoint.Builder {
      @Override
      public Polygon build() {
        return new Polygon(this);
      }
    }
  }
// MultiPolygon类型
  public static class MultiPolygon extends BaseGeoJson {
    private double[][][][] coordinates;
    MultiPolygon(Builder builder) {
      super(builder);
      this.type = GeoJsonType.MultiPolygon;
      this.coordinates = new double[][][][]{builder.convert2Array()};
    }
    @Override
    protected Object coordinates() {
      return this.coordinates;
    }
    public static class Builder extends BaseGeoJson.Builder {
      private List<Polygon> polygons = new LinkedList<>();
      @Override
      public BaseGeoJson build() {
        return new MultiPolygon(this);
      }
      void addPolygon(Polygon polygon) {
        polygons.add(polygon);
      }
      private double[][][] convert2Array() {
        int length = this.polygons.size();
        double[][][] result = new double[length][][];
        for (int i = 0; i < length; i++) {
          result[i] = this.polygons.get(i).convert2Array();
        }
        return result;
      }
    }
    static class Polygon {
      private List<Coordinate> coordinates;
      private Builder builder;
      Polygon(Builder builder) {
        this.builder = builder;
        this.builder.addPolygon(this);
      }
      private double[][] convert2Array() {
        int length = this.coordinates.size();
        double[][] result = new double[length][];
        for (int i = 0; i < length; i++) {
          result[i] = this.coordinates.get(i).convertToArray();
        }
        return result;
      }
      public Polygon coordinate(double lon, double lat) {
        if (CollectionUtils.isEmpty(this.coordinates)) {
          this.coordinates = new LinkedList<>();
        }
        this.coordinates.add(new Coordinate(lat, lon));
        return this;
      }
      public Polygon nextLine() {
        return new Polygon(this.builder);
      }
      public Builder end() {
        return this.builder;
      }
    }
  }
// 基类BaseGeoJson
  public abstract static class BaseGeoJson extends Element {
    // 公共字段type
    protected GeoJsonType type;
    // 公共字段metadata
    private Map<String, String> metadata;
    BaseGeoJson(Builder builder) {
      this.metadata = builder.metadata;
    }
    protected abstract Object coordinates();
    // 转换成命令参数
    @Override
    public List<String> commandArgs() {
      List<String> result = new LinkedList<>();
      result.add("OBJECT");
      result.add(toJson());
      return result;
    }
    // 提供统一的转json方法
    protected String toJson() {
      Map<String, Object> map = new LinkedHashMap<>();
      map.put("type", this.type);
      map.put("coordinates", coordinates());
      if (!CollectionUtils.isEmpty(this.metadata)) {
        for (Map.Entry<String, String> entry : this.metadata.entrySet()) {
          map.put(entry.getKey(), entry.getValue());
        }
      }
      return JsonUtil.obj2String(map);
    }
    abstract static class Builder {
      private Map<String, String> metadata;
      public Builder meta(String key, String value) {
        if (MapUtils.isEmpty(this.metadata)) {
          this.metadata = new LinkedHashMap<>();
        }
        this.metadata.put(key, value);
        return this;
      }
      public abstract BaseGeoJson build();
    }
    static class Coordinate {
      private double lat;
      private double lon;
      Coordinate(double lat, double lon) {
        this.lat = lat;
        this.lon = lon;
      }
      public double[] convertToArray() {
        return new double[]{this.lat, this.lon};
      }
    }
    // GeoJSON所有的数据类型
    enum GeoJsonType {
      Point,
      LineString,
      Polygon,
      MultiPoint,
      MultiLineString,
      MultiPolygon
    }
  }

Finally, add a base class Element:

public abstract class Element implements Serializable {
  public abstract List<String> commandArgs();
}

How to use

We All data types are converted into specific code designs. Let’s see how to use them:

private String setElement(SetOpts setOpts, Element element) {
    List<String> args1 = setOpts.commandLine();
    List<String> commandArgs = element.commandArgs();
    return execute(Tile38Command.SET, args1, commandArgs);
}
/**
   * 设置点位
   *
   * @param setOpts
   * @param point
   * @return
   */
  public String setPoint(SetOpts setOpts, Point point) {
    return setElement(setOpts, point);
  }
  /**
   * 设置对象
   *
   * @param setOpts
   * @param geoJson
   * @return
   */
  public String setObject(SetOpts setOpts, GeoJson.BaseGeoJson geoJson) {
    return setElement(setOpts, geoJson);
  }
  /**
   * 设置矩形边界
   *
   * @param setOpts
   * @param bounds
   * @return
   */
  public String setBounds(SetOpts setOpts, Bounds bounds) {
    return setElement(setOpts, bounds);
  }
  /**
   * 设置geohash
   *
   * @param setOpts
   * @param geohash
   * @return
   */
  public String setGeohash(SetOpts setOpts, Geohash geohash) {
    return setElement(setOpts, geohash);
  }
  /**
   * 设置String
   *
   * @param setOpts
   * @param string
   * @return
   */
  public String setString(SetOpts setOpts, RawString string) {
    return setElement(setOpts, string);
  }

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