聊聊RedisToken

序

本文主要研究一下RedisToken

RedisToken

resp-server-0.16.0/src/main/java/com/github/tonivade/resp/protocol/RedisToken.java

public interface RedisToken {
  RedisToken NULL_STRING = string((SafeString) null);
  RedisToken RESPONSE_OK = status("OK");

  RedisTokenType getType();

  <T> T accept(RedisTokenVisitor<T> visitor);

  static RedisToken nullString() {
    return NULL_STRING;
  }

  static RedisToken responseOk() {
    return RESPONSE_OK;
  }

  static RedisToken string(SafeString str) {
    return new StringRedisToken(str);
  }

  static RedisToken string(String str) {
    return new StringRedisToken(safeString(str));
  }

  static RedisToken status(String str) {
    return new StatusRedisToken(str);
  }

  static RedisToken integer(boolean b) {
    return new IntegerRedisToken(b ? 1 : 0);
  }

  static RedisToken integer(int i) {
    return new IntegerRedisToken(i);
  }

  static RedisToken error(String str) {
    return new ErrorRedisToken(str);
  }

  static RedisToken array(RedisToken... redisTokens) {
    return new ArrayRedisToken(ImmutableList.of(redisTokens));
  }

  static RedisToken array(Collection<RedisToken> redisTokens) {
    return new ArrayRedisToken(ImmutableList.from(redisTokens));
  }

  static RedisToken array(Sequence<RedisToken> redisTokens) {
    return new ArrayRedisToken(redisTokens.asArray());
  }

  static <T> Stream<T> visit(Stream<RedisToken> tokens, RedisTokenVisitor<T> visitor) {
    return tokens.map(token -> token.accept(visitor));
  }
}

• RedisToken接口定义了getType、accept方法；它还提供了nullString、responseOk、string、status、integer、error、array、visit静态方法

AbstractRedisToken

resp-server-0.16.0/src/main/java/com/github/tonivade/resp/protocol/AbstractRedisToken.java

public abstract class AbstractRedisToken<T> implements RedisToken {

  private static final String SEPARATOR = "=>";
  private static final Equal<AbstractRedisToken<?>> EQUAL =
      Equal.<AbstractRedisToken<?>>of()
          .comparing(AbstractRedisToken::getType)
          .comparing(AbstractRedisToken::getValue);

  private final RedisTokenType type;
  private final T value;

  private AbstractRedisToken(RedisTokenType type, T value) {
    this.type = requireNonNull(type);
    this.value = value;
  }

  @Override
  public RedisTokenType getType() {
    return type;
  }

  public T getValue() {
    return value;
  }

  @Override
  public int hashCode() {
    return Objects.hash(type, value);
  }

  @Override
  public boolean equals(Object obj) {
    return EQUAL.applyTo(this, obj);
  }

  @Override
  public String toString() {
    return type + SEPARATOR + value;
  }

}

• AbstractRedisToken声明实现RedisToken接口，它的构造器要求输入type、value

UnknownRedisToken

resp-server-0.16.0/src/main/java/com/github/tonivade/resp/protocol/AbstractRedisToken.java

  public static final class UnknownRedisToken extends AbstractRedisToken<SafeString> {

    UnknownRedisToken(SafeString value) {
      super(RedisTokenType.UNKNOWN, value);
    }

    @Override
    public <T> T accept(RedisTokenVisitor<T> visitor) {
      return visitor.unknown(this);
    }
  }

• UnknownRedisToken继承了AbstractRedisToken，其value为SafeString类型，其type为RedisTokenType.UNKNOWN，其accept执行的是visitor.unknown(this)

StringRedisToken

resp-server-0.16.0/src/main/java/com/github/tonivade/resp/protocol/AbstractRedisToken.java

  public static final class StringRedisToken extends AbstractRedisToken<SafeString> {

    StringRedisToken(SafeString value) {
      super(RedisTokenType.STRING, value);
    }

    @Override
    public <T> T accept(RedisTokenVisitor<T> visitor) {
      return visitor.string(this);
    }
  }

• StringRedisToken继承了AbstractRedisToken，其value为SafeString，其type为RedisTokenType.STRING，其accept执行的是visitor.string(this)

StatusRedisToken

resp-server-0.16.0/src/main/java/com/github/tonivade/resp/protocol/AbstractRedisToken.java

  public static final class StatusRedisToken extends AbstractRedisToken<String> {

    StatusRedisToken(String value) {
      super(RedisTokenType.STATUS, value);
    }

    @Override
    public <T> T accept(RedisTokenVisitor<T> visitor) {
      return visitor.status(this);
    }
  }

• StatusRedisToken继承了AbstractRedisToken，其value为String，其type为RedisTokenType.STATUS，其accept执行的是visitor.status(this)

ErrorRedisToken

resp-server-0.16.0/src/main/java/com/github/tonivade/resp/protocol/AbstractRedisToken.java

  public static final class ErrorRedisToken extends AbstractRedisToken<String> {

    ErrorRedisToken(String value) {
      super(RedisTokenType.ERROR, value);
    }

    @Override
    public <T> T accept(RedisTokenVisitor<T> visitor) {
      return visitor.error(this);
    }
  }

• ErrorRedisToken继承了AbstractRedisToken，其value为String，其type为RedisTokenType.ERROR，其accept执行的是visitor.error(this)

IntegerRedisToken

resp-server-0.16.0/src/main/java/com/github/tonivade/resp/protocol/AbstractRedisToken.java

  public static final class IntegerRedisToken extends AbstractRedisToken<Integer> {

    IntegerRedisToken(Integer value) {
      super(RedisTokenType.INTEGER, value);
    }

    @Override
    public <T> T accept(RedisTokenVisitor<T> visitor) {
      return visitor.integer(this);
    }
  }

• IntegerRedisToken继承了AbstractRedisToken，其value为Integer，其type为RedisTokenType.INTEGER，其accept执行的是visitor.integer(this)

ArrayRedisToken

resp-server-0.16.0/src/main/java/com/github/tonivade/resp/protocol/AbstractRedisToken.java

  public static final class ArrayRedisToken extends AbstractRedisToken<Sequence<RedisToken>> {

    ArrayRedisToken(Sequence<RedisToken> value) {
      super(RedisTokenType.ARRAY, requireNonNull(value).asArray());
    }

    @Override
    public <T> T accept(RedisTokenVisitor<T> visitor) {
      return visitor.array(this);
    }

    public int size() {
      return getValue().size();
    }
  }

• ArrayRedisToken继承了AbstractRedisToken，其value为Sequence<RedisToken>，其type为RedisTokenType.ARRAY，其accept执行的是visitor.array(this)

小结

RedisToken接口定义了getType、accept方法；它还提供了nullString、responseOk、string、status、integer、error、array、visit静态方法；AbstractRedisToken声明实现RedisToken接口，它的构造器要求输入type、value，它有UnknownRedisToken、StringRedisToken、StatusRedisToken、ErrorRedisToken、IntegerRedisToken、ArrayRedisToken这些实现类

doc

• RedisToken