be.ceau.chart.objects.OptionalArray.java Source code

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Here is the source code for be.ceau.chart.objects.OptionalArray.java

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/*
   Copyright 2016 Marceau Dewilde <m@ceau.be>
    
   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 be.ceau.chart.objects;

import java.io.IOException;
import java.util.ArrayList;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;

/**
 * ArrayList subclass with special serialization behavior: if only one item
 * contained, the item will be serialized as a single value.
 */
@JsonSerialize(using = OptionalArray.Serializer.class)
public class OptionalArray<E> extends ArrayList<E> {

    private static final long serialVersionUID = 1470940649764L;

    public static class Serializer<T> extends JsonSerializer<OptionalArray<T>> {

        @Override
        public boolean isEmpty(SerializerProvider provider, OptionalArray<T> value) {
            return value == null || value.isEmpty();
        }

        @Override
        public void serialize(OptionalArray<T> value, JsonGenerator jgen, SerializerProvider provider)
                throws IOException, JsonProcessingException {
            if (value != null && !value.isEmpty()) {
                if (value.size() == 1) {
                    jgen.writeObject(value.get(0));
                } else {
                    jgen.writeStartArray();
                    for (T t : value) {
                        jgen.writeObject(t);
                    }
                    jgen.writeEndArray();
                }
            }
        }

    }

}