Mmuzaf commented on code in PR #2133: URL: https://github.com/apache/cassandra/pull/2133#discussion_r1149840265
########## src/java/org/apache/cassandra/config/StringConverters.java: ########## @@ -0,0 +1,104 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.cassandra.config; + +import org.apache.cassandra.config.registry.TypeConverter; +import org.apache.cassandra.db.ConsistencyLevel; + +import static org.apache.cassandra.config.registry.PrimitiveUnaryConverter.convertSafe; + +/** + * String converters for Cassandra configuration types used in {@link Config}. These are used to convert + * configuration values from their string representation to their actual type and back. The converters + * are uses the {@link TypeConverter} interface. + * <p> + * Take care when adding new converters, only one converter per type is allowed. If a converter for a + * type already exists, the new converter will be ignored since the first converter for a type is used. + * + * @see Config + * @see TypeConverter + */ +public enum StringConverters +{ + PRIMITIVE_BOOLEAN(Boolean.TYPE, s -> Boolean.parseBoolean((String) s), b -> Boolean.toString((Boolean) b)), + PRIMITIVE_DOUBLE(Double.TYPE, s -> Double.parseDouble((String) s), d -> Double.toString((Double) d)), + PRIMITIVE_INTEGER(Integer.TYPE, s -> Integer.parseInt((String) s), i -> Integer.toString((Integer) i)), + PRIMITIVE_LONG(Long.TYPE, s -> Long.parseLong((String) s), l -> Long.toString((Long) l)), + BOOLEAN(Boolean.class, s -> Boolean.parseBoolean((String) s), b -> Boolean.toString((Boolean) b)), + DOUBLE(Double.class, s -> Double.parseDouble((String) s), d -> Double.toString((Double) d)), + INTEGER(Integer.class, s -> Integer.parseInt((String) s), i -> Integer.toString((Integer) i)), + LONG(Long.class, s -> Long.parseLong((String) s), l -> Long.toString((Long) l)), + STRING(String.class, s -> (String) s, s -> (String) s), + // Cassandra specific configuration types. + LONG_NANOSECONDS_BOUND(DurationSpec.LongNanosecondsBound.class, s -> new DurationSpec.LongNanosecondsBound((String) s), TypeConverter.DEFAULT), + LONG_MILLISECONDS_BOUND(DurationSpec.LongMillisecondsBound.class, s -> new DurationSpec.LongMillisecondsBound((String) s), TypeConverter.DEFAULT), + LONG_SECONDS_BOUND(DurationSpec.LongSecondsBound.class, s -> new DurationSpec.LongSecondsBound((String) s), TypeConverter.DEFAULT), + INT_MINUSTES_BOUND(DurationSpec.IntMinutesBound.class, s -> new DurationSpec.IntMinutesBound((String) s), TypeConverter.DEFAULT), + INT_SECONDS_BOUND(DurationSpec.IntSecondsBound.class, s -> new DurationSpec.IntSecondsBound((String) s), TypeConverter.DEFAULT), + INT_MILLISECONDS_BOUND(DurationSpec.IntMillisecondsBound.class, s -> new DurationSpec.IntMillisecondsBound((String) s), TypeConverter.DEFAULT), + LONG_BYTES_BOUND(DataStorageSpec.LongBytesBound.class, s -> new DataStorageSpec.LongBytesBound((String) s), TypeConverter.DEFAULT), + INT_BYTES_BOUND(DataStorageSpec.IntBytesBound.class, s -> new DataStorageSpec.IntBytesBound((String) s), TypeConverter.DEFAULT), + INT_KIBIBYTES_BOUND(DataStorageSpec.IntKibibytesBound.class, s -> new DataStorageSpec.IntKibibytesBound((String) s), TypeConverter.DEFAULT), + LONG_MEBIBYTES_BOUND(DataStorageSpec.LongMebibytesBound.class, s -> new DataStorageSpec.LongMebibytesBound((String) s), TypeConverter.DEFAULT), + INT_MEBIBYTES_BOUND(DataStorageSpec.IntMebibytesBound.class, s -> new DataStorageSpec.IntMebibytesBound((String) s), TypeConverter.DEFAULT), + CONSYSTENCY_LEVEL(ConsistencyLevel.class, s -> ConsistencyLevel.fromStringIgnoreCase((String) s), c -> ((ConsistencyLevel) c).name()); + + private final Class<?> type; + private final TypeConverter<?> forward; + private final TypeConverter<String> reverse; + + /** + * Creates a new converter for the given type and using the given converters. + * @param type the type this converter converts to and from. + * @param forward the forward converter to use. + * @param reverse the reverse converter to use. + */ + <T> StringConverters(Class<T> type, TypeConverter<T> forward, TypeConverter<String> reverse) + { + this.type = type; + this.forward = forward; + this.reverse = reverse; + } + public <T> T fromString(String value, Class<T> target) + { + if (target.equals(type)) + return convertSafe(type, forward.convertNullable(value)); + throw new IllegalArgumentException(String.format("Invalid target type '%s' for converter '%s'", target, this)); + } + + public String toString(Object value) + { + return reverse.convertNullable(value); + } + + /** + * Returns the converter for the given type. + * @param type the type to return the converter for. + * @return the converter for the given type or {@code null} if no converter exists for the given type + * or default conversion should be used instead. + */ + public static StringConverters fromType(Class<?> type) + { + for (StringConverters converter : values()) + if (converter.type.equals(type)) + return converter; + + return null; + } Review Comment: I think you're right here, we don't need such complexity with `Enum`s and the `Map` is the easiest solution for us. -- This is an automated message from the Apache Git Service. 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