com.google.cloud.dataflow.sdk.coders.ListCoder Maven / Gradle / Ivy
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Google Cloud Dataflow Java SDK provides a simple, Java-based
interface for processing virtually any size data using Google cloud
resources. This artifact includes entire Dataflow Java SDK.
/*
* Copyright (C) 2015 Google Inc.
*
* Licensed 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.google.cloud.dataflow.sdk.coders;
import static com.google.common.base.Preconditions.checkArgument;
import com.google.cloud.dataflow.sdk.util.PropertyNames;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.List;
/**
* A {@link Coder} for {@link List}, using the format of {@link IterableLikeCoder}.
*
* @param the type of the elements of the Lists being transcoded
*/
public class ListCoder extends IterableLikeCoder> {
public static ListCoder of(Coder elemCoder) {
return new ListCoder<>(elemCoder);
}
/////////////////////////////////////////////////////////////////////////////
// Internal operations below here.
@Override
protected final List decodeToIterable(List decodedElements) {
return decodedElements;
}
@JsonCreator
public static ListCoder of(
@JsonProperty(PropertyNames.COMPONENT_ENCODINGS)
List> components) {
checkArgument(components.size() == 1, "Expecting 1 component, got " + components.size());
return of((Coder) components.get(0));
}
/**
* Returns the first element in this list if it is non-empty,
* otherwise returns {@code null}.
*/
public static List