Refactor converters.

Prefer lambda-style converters. Replace indirections via Converters API with method references.

Original Pull Request: #1960

Author: mp911de

src/main/java/org/springframework/data/redis/connection/convert/Converters.java

@@ -21,6 +21,7 @@
 import java.util.stream.Collectors;
 
 import org.springframework.core.convert.converter.Converter;
+import org.springframework.lang.NonNull;
 import org.springframework.util.Assert;
 
 /**
@@ -33,7 +34,7 @@
  */
 public class SetConverter<S, T> implements Converter<Set<S>, Set<T>> {
 
-	private Converter<S, T> itemConverter;
+	private final Converter<S, T> itemConverter;
 
 	/**
 	 * @param itemConverter The {@link Converter} to use for converting individual Set items. Must not be {@literal null}.
@@ -49,6 +50,7 @@ public SetConverter(Converter<S, T> itemConverter) {
 	 * @see org.springframework.core.convert.converter.Converter#convert(Object)
 	 */
 	@Override
+	@NonNull
 	public Set<T> convert(Set<S> source) {
 
 		return source.stream().map(itemConverter::convert)

src/main/java/org/springframework/data/redis/connection/convert/SetConverter.java

@@ -21,6 +21,7 @@
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.data.redis.core.types.RedisClientInfo;
 import org.springframework.data.redis.core.types.RedisClientInfo.RedisClientInfoBuilder;
+import org.springframework.lang.NonNull;
 
 /**
  * {@link Converter} implementation to create one {@link RedisClientInfo} per line entry in given {@link String} array.
@@ -42,6 +43,7 @@ public class StringToRedisClientInfoConverter implements Converter<String[], Lis
 	 * @see org.springframework.core.convert.converter.Converter#convert(Object)
 	 */
 	@Override
+	@NonNull
 	public List<RedisClientInfo> convert(String[] lines) {
 
 		List<RedisClientInfo> clientInfoList = new ArrayList<>(lines.length);

src/main/java/org/springframework/data/redis/connection/convert/StringToRedisClientInfoConverter.java

@@ -24,6 +24,7 @@
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.data.redis.connection.ClusterSlotHashUtil;
 import org.springframework.data.redis.connection.RedisZSetCommands;
+import org.springframework.data.redis.connection.convert.SetConverter;
 import org.springframework.data.redis.core.Cursor;
 import org.springframework.data.redis.core.ScanCursor;
 import org.springframework.data.redis.core.ScanIteration;
@@ -40,6 +41,8 @@
  */
 class JedisClusterZSetCommands implements RedisZSetCommands {
 
+	private static final SetConverter<redis.clients.jedis.Tuple, Tuple> TUPLE_SET_CONVERTER = new SetConverter<>(
+			JedisConverters::toTuple);
 	private final JedisClusterConnection connection;
 
 	JedisClusterZSetCommands(JedisClusterConnection connection) {
@@ -181,9 +184,9 @@ public Set<Tuple> zRangeByScoreWithScores(byte[] key, Range range, Limit limit)
 
 		try {
 			if (limit.isUnlimited()) {
-				return JedisConverters.toTupleSet(connection.getCluster().zrangeByScoreWithScores(key, min, max));
+				return toTupleSet(connection.getCluster().zrangeByScoreWithScores(key, min, max));
 			}
-			return JedisConverters.toTupleSet(
+			return toTupleSet(
 					connection.getCluster().zrangeByScoreWithScores(key, min, max, limit.getOffset(), limit.getCount()));
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
@@ -228,9 +231,9 @@ public Set<Tuple> zRevRangeByScoreWithScores(byte[] key, Range range, Limit limi
 
 		try {
 			if (limit.isUnlimited()) {
-				return JedisConverters.toTupleSet(connection.getCluster().zrevrangeByScoreWithScores(key, max, min));
+				return toTupleSet(connection.getCluster().zrevrangeByScoreWithScores(key, max, min));
 			}
-			return JedisConverters.toTupleSet(
+			return toTupleSet(
 					connection.getCluster().zrevrangeByScoreWithScores(key, max, min, limit.getOffset(), limit.getCount()));
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
@@ -379,7 +382,7 @@ public Set<Tuple> zRangeWithScores(byte[] key, long start, long end) {
 		Assert.notNull(key, "Key must not be null!");
 
 		try {
-			return JedisConverters.toTupleSet(connection.getCluster().zrangeWithScores(key, start, end));
+			return toTupleSet(connection.getCluster().zrangeWithScores(key, start, end));
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
 		}
@@ -411,7 +414,7 @@ public Set<Tuple> zRangeByScoreWithScores(byte[] key, double min, double max) {
 		Assert.notNull(key, "Key must not be null!");
 
 		try {
-			return JedisConverters.toTupleSet(connection.getCluster().zrangeByScoreWithScores(key, min, max));
+			return toTupleSet(connection.getCluster().zrangeByScoreWithScores(key, min, max));
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
 		}
@@ -452,7 +455,7 @@ public Set<Tuple> zRangeByScoreWithScores(byte[] key, double min, double max, lo
 		}
 
 		try {
-			return JedisConverters.toTupleSet(connection.getCluster().zrangeByScoreWithScores(key, min, max,
+			return toTupleSet(connection.getCluster().zrangeByScoreWithScores(key, min, max,
 					Long.valueOf(offset).intValue(), Long.valueOf(count).intValue()));
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
@@ -485,7 +488,7 @@ public Set<Tuple> zRevRangeWithScores(byte[] key, long start, long end) {
 		Assert.notNull(key, "Key must not be null!");
 
 		try {
-			return JedisConverters.toTupleSet(connection.getCluster().zrevrangeWithScores(key, start, end));
+			return toTupleSet(connection.getCluster().zrevrangeWithScores(key, start, end));
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
 		}
@@ -517,7 +520,7 @@ public Set<Tuple> zRevRangeByScoreWithScores(byte[] key, double min, double max)
 		Assert.notNull(key, "Key must not be null!");
 
 		try {
-			return JedisConverters.toTupleSet(connection.getCluster().zrevrangeByScoreWithScores(key, max, min));
+			return toTupleSet(connection.getCluster().zrevrangeByScoreWithScores(key, max, min));
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
 		}
@@ -558,7 +561,7 @@ public Set<Tuple> zRevRangeByScoreWithScores(byte[] key, double min, double max,
 		}
 
 		try {
-			return JedisConverters.toTupleSet(connection.getCluster().zrevrangeByScoreWithScores(key, max, min,
+			return toTupleSet(connection.getCluster().zrevrangeByScoreWithScores(key, max, min,
 					Long.valueOf(offset).intValue(), Long.valueOf(count).intValue()));
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
@@ -819,4 +822,8 @@ private DataAccessException convertJedisAccessException(Exception ex) {
 		return connection.convertJedisAccessException(ex);
 	}
 
+	private static Set<Tuple> toTupleSet(Set<redis.clients.jedis.Tuple> source) {
+		return TUPLE_SET_CONVERTER.convert(source);
+	}
+
 }