[IOTDB-1463] Implement builder pattern for Session and SessionPool

docs/UserGuide/API/Programming-Java-Native-API.md

@@ -56,11 +56,21 @@ Here we show the commonly used interfaces and their parameters in the Native API
 * Initialize a Session
 
 ```java
-Session(String host, int rpcPort)
-
-Session(String host, String rpcPort, String username, String password)
-
-Session(String host, int rpcPort, String username, String password)
+    // use default configuration 
+    session = new Session.Builder.build();
+
+    // configure all fields
+    session = 
+        new Session.Builder()
+            .host(String host)
+            .port(int port)
+            .fetchSize(int fetchSize)
+            .username(String username)
+            .password(String password)
+            .thriftDefaultBufferSize(int thriftDefaultBufferSize)
+            .thriftMaxFrameSize(int thriftMaxFrameSize)
+            .enableCacheLeader(boolean enableCacheLeader)
+            .build();
 ```
 
 * Open a Session

docs/zh/UserGuide/API/Programming-Java-Native-API.md

@@ -59,9 +59,21 @@ mvn clean install -pl session -am -Dmaven.test.skip=true
 * 初始化Session
 
 ```java
-Session(String host, int rpcPort)
-Session(String host, String rpcPort, String username, String password)
-Session(String host, int rpcPort, String username, String password)
+    // 全部使用默认配置
+    session = new Session.Builder.build();
+
+    // 自行配置参数
+    session = 
+        new Session.Builder()
+            .host(String host)
+            .port(int port)
+            .fetchSize(int fetchSize)
+            .username(String username)
+            .password(String password)
+            .thriftDefaultBufferSize(int thriftDefaultBufferSize)
+            .thriftMaxFrameSize(int thriftMaxFrameSize)
+            .enableCacheLeader(boolean enableCacheLeader)
+            .build();
 ```
 
 * 开启Session

example/session/src/main/java/org/apache/iotdb/SessionExample.java

@@ -53,7 +53,8 @@ public class SessionExample {
 
   public static void main(String[] args)
       throws IoTDBConnectionException, StatementExecutionException {
-    session = new Session(LOCAL_HOST, 6667, "root", "root");
+    session =
+        new Session.Builder().host(LOCAL_HOST).port(6667).username("root").password("root").build();
     session.open(false);
 
     // set session fetchSize

example/session/src/main/java/org/apache/iotdb/SessionPoolExample.java

@@ -37,7 +37,14 @@ public class SessionPoolExample {
 
   public static void main(String[] args)
       throws StatementExecutionException, IoTDBConnectionException, InterruptedException {
-    pool = new SessionPool("127.0.0.1", 6667, "root", "root", 3);
+    pool =
+        new SessionPool.Builder()
+            .host("127.0.0.1")
+            .port(6667)
+            .user("root")
+            .password("root")
+            .maxSize(3)
+            .build();
     service = Executors.newFixedThreadPool(10);
 
     insertRecord();

session/src/main/java/org/apache/iotdb/session/Config.java

@@ -20,6 +20,8 @@
 
 public class Config {
 
+  public static final String DEFAULT_HOST = "localhost";
+  public static final int DEFAULT_PORT = 6667;
   public static final String DEFAULT_USER = "root";
   public static final String DEFAULT_PASSWORD = "root";
   public static final int DEFAULT_FETCH_SIZE = 5000;
@@ -34,4 +36,6 @@ public class Config {
 
   /** thrift max frame size (16384000 bytes by default), we change it to 64MB */
   public static final int DEFAULT_MAX_FRAME_SIZE = 67108864;
+
+  public static final int DEFAULT_SESSION_POOL_MAX_SIZE = 5;
 }

session/src/main/java/org/apache/iotdb/session/Session.java

@@ -1833,4 +1833,69 @@ public boolean isEnableQueryRedirection() {
   public void setEnableQueryRedirection(boolean enableQueryRedirection) {
     this.enableQueryRedirection = enableQueryRedirection;
   }
+
+  public static class Builder {
+    private String host = Config.DEFAULT_HOST;
+    private int rpcPort = Config.DEFAULT_PORT;
+    private String username = Config.DEFAULT_USER;
+    private String password = Config.DEFAULT_PASSWORD;
+    private int fetchSize = Config.DEFAULT_FETCH_SIZE;
+    private ZoneId zoneId = null;
+    private int thriftDefaultBufferSize = Config.DEFAULT_INITIAL_BUFFER_CAPACITY;
+    private int thriftMaxFrameSize = Config.DEFAULT_MAX_FRAME_SIZE;
+    private boolean enableCacheLeader = Config.DEFAULT_CACHE_LEADER_MODE;
+
+    public Builder host(String host) {
+      this.host = host;
+      return this;
+    }
+
+    public Builder port(int port) {
+      this.rpcPort = port;
+      return this;
+    }
+
+    public Builder username(String username) {
+      this.username = username;
+      return this;
+    }
+
+    public Builder password(String password) {
+      this.password = password;
+      return this;
+    }
+
+    public Builder fetchSize(int fetchSize) {
+      this.fetchSize = fetchSize;
+      return this;
+    }
+
+    public Builder thriftDefaultBufferSize(int thriftDefaultBufferSize) {
+      this.thriftDefaultBufferSize = thriftDefaultBufferSize;
+      return this;
+    }
+
+    public Builder thriftMaxFrameSize(int thriftMaxFrameSize) {
+      this.thriftMaxFrameSize = thriftMaxFrameSize;
+      return this;
+    }
+
+    public Builder enableCacheLeader(boolean enableCacheLeader) {
+      this.enableCacheLeader = enableCacheLeader;
+      return this;
+    }
+
+    public Session build() {
+      return new Session(
+          host,
+          rpcPort,
+          username,
+          password,
+          fetchSize,
+          zoneId,
+          thriftDefaultBufferSize,
+          thriftMaxFrameSize,
+          enableCacheLeader);
+    }
+  }
 }