com.datastax.oss.driver.internal.core.type.codec.extras.OptionalCodec Maven / Gradle / Ivy
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/*
* 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 com.datastax.oss.driver.internal.core.type.codec.extras;
import com.datastax.oss.driver.api.core.type.codec.MappingCodec;
import com.datastax.oss.driver.api.core.type.codec.TypeCodec;
import com.datastax.oss.driver.api.core.type.reflect.GenericType;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import java.util.Collection;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import net.jcip.annotations.Immutable;
/**
* A codec that wraps other codecs around {@link Optional} instances.
*
* @param The wrapped Java type.
*/
@Immutable
public class OptionalCodec extends MappingCodec> {
public OptionalCodec(@NonNull TypeCodec innerCodec) {
super(
Objects.requireNonNull(innerCodec, "innerCodec must not be null"),
GenericType.optionalOf(innerCodec.getJavaType()));
}
@Override
public boolean accepts(@NonNull Object value) {
Objects.requireNonNull(value);
if (value instanceof Optional) {
Optional optional = (Optional) value;
return optional.map(innerCodec::accepts).orElse(true);
}
return false;
}
@Nullable
@Override
protected Optional innerToOuter(@Nullable T value) {
return Optional.ofNullable(isAbsent(value) ? null : value);
}
@Nullable
@Override
protected T outerToInner(@Nullable Optional value) {
return value != null && value.isPresent() ? value.get() : null;
}
protected boolean isAbsent(@Nullable T value) {
return value == null
|| (value instanceof Collection && ((Collection) value).isEmpty())
|| (value instanceof Map && ((Map) value).isEmpty());
}
}