解析Springboot集成Tile38客户端之Set命令实现示例
目录
- set命令语法
- 语法分析
- 代码设计
- POINT数据类型
- BOUNDS数据类型
- HASH和STRING数据类型
- OBJECT数据类型
- 如何使用
set命令语法
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
命令就相当于redis中的hash
命令的使用,也是一个key
和id
的组合,但是不同的是,Tile38的set
命令还可以携带更多的其他属性,比如可以自定义FIELD
字段,还可以设置EX
有效期等等,那么我们需要给这个语法设计一套好用的java api
,以便开发人员可以更好地使用Tile38。
语法分析
首先,根据上面提供的语法,我们可以分为三部分:
1.第一部分就是命令的启示关键字SET
,我们把这个关键字单独作为一部分;
2.第二部分就是key id [FIELD name value ...] [EX seconds] [NX|XX]
,我们把这些都作为参数;
3.第三部分就是最后的目标数据对象:
(OBJECT geojson)|(POINT lat lon z)|(BOUNDS minlat minlon maxlat maxlon)|(HASH geohash)|(STRING value)
代码设计
1.我们把第一部分的命令关键字通过枚举的方式来管理:
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; } }
因为redis客户端工具在发送命令前需要对所有命令进行编码,所以要求所有的命令都必须实现ProtocolKeyword
接口。如果命令的起始关键字是两个或多个单词,那么我们会使用下划线连接,转换成bytes的时候我们可以使用空格把下划线替换。
2.我们把命令的第二部分抽象成一个具体的class,通过相关的字段来进行描述:
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); } } }
我们上面通过建造者的设计模式,把所有的参数都转换成了SetOpts这个类当中,开发人员就可以通过SetOpts对象的构建来灵活地控制命令中的参数了。
3.我们需要把第三部分当中的不同数据对象转换成不同的类型:
POINT数据类型
Point关键的字段就是经纬度,除此之外,还有一个额外的字段z
,用来存储额外的业务参数,可为空。
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数据类型
BOUNDS就是矩形,它的关键字段就是左下角和右上角两个点位,我们使用coordinate1和coordinate2来表示左下角和右上角;
@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和STRING数据类型
HASH和STRING其实就是一个单独的字符串,但是我们还是把它封装一下,以便开发人员使用;
@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数据类型
OBJECT其实就是GeoJSON数据,这一类数据比较复杂一点,一共有六种类型,想了解的小伙伴可以看这里geojson.org/
Point, LineString, Polygon, MultiPoint, MultiLineString, MultiPolygon
为了开发人员能够更好的使用这六种类型,我们同样使用建造者模式来设计一下GeoJSON数据类型:
@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(); } } }
我们现在一个大类里面创建多个方法,每一个方法都把对应类型的建造者给创造出来,这样的话,就相当于这个类当中有创建六种对象的方式,每个建造者都只负责建造对应的那个对象。
下面分别是六个建造者的代码,每个对象都基于最基本的BaseGeoJson来构造,BaseGeoJson中把公共的字段type和额外的meta字段抽出来,各个类型不同的点在于坐标点的数量和层次不同,所以根据各自类型的特点,代码设计如下:
// 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 } }
最后,再补充一个基类Element:
public abstract class Element implements Serializable { public abstract List<String> commandArgs(); }
如何使用
我们针对所有的数据类型全部转换成具体的代码设计,下面我们看看如何使用:
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); }
所有的开发人员只需要按照上面的方法来使用就可以很方便地执行Tile38的命令了,至此,我们所有关于SET
命令的设计都已经讲解完毕。
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