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/*
 * Copyright 2013 Nicolas Morel
 *
 * 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 org.dominokit.jacksonapt.ser;

import org.dominokit.jacksonapt.JsonSerializationContext;
import org.dominokit.jacksonapt.JsonSerializer;
import org.dominokit.jacksonapt.JsonSerializerParameters;
import org.dominokit.jacksonapt.stream.JsonWriter;

import java.util.Iterator;

/**
 * Default {@link org.dominokit.jacksonapt.JsonSerializer} implementation for {@link java.lang.Iterable}.
 *
 * @param  Type of the elements inside the {@link java.lang.Iterable}
 * @author Nicolas Morel
 * @version $Id: $
 */
public class IterableJsonSerializer, T> extends JsonSerializer {

    /**
     * newInstance
     *
     * @param serializer {@link org.dominokit.jacksonapt.JsonSerializer} used to serialize the objects inside the {@link java.lang.Iterable}
     * @param   Type of the {@link Iterable}
     * @return a new instance of {@link org.dominokit.jacksonapt.ser.IterableJsonSerializer}
     */
    public static > IterableJsonSerializer newInstance(JsonSerializer serializer) {
        return new IterableJsonSerializer(serializer);
    }

    protected final JsonSerializer serializer;

    /**
     * Constructor for IterableJsonSerializer.
     *
     * @param serializer {@link org.dominokit.jacksonapt.JsonSerializer} used to serialize the objects inside the {@link java.lang.Iterable}.
     */
    protected IterableJsonSerializer(JsonSerializer serializer) {
        if (null == serializer) {
            throw new IllegalArgumentException("serializer cannot be null");
        }
        this.serializer = serializer;
    }

    /** {@inheritDoc} */
    @Override
    protected boolean isEmpty(I value) {
        return null == value || !value.iterator().hasNext();
    }

    /** {@inheritDoc} */
    @Override
    public void doSerialize(JsonWriter writer, I values, JsonSerializationContext ctx, JsonSerializerParameters params) {
        Iterator iterator = values.iterator();

        if (!iterator.hasNext()) {
            if (ctx.isWriteEmptyJsonArrays()) {
                writer.beginArray();
                writer.endArray();
            } else {
                writer.cancelName();
            }
            return;
        }

        if (ctx.isWriteSingleElemArraysUnwrapped()) {

            T first = iterator.next();

            if (iterator.hasNext()) {
                // there is more than one element, we write the array normally
                writer.beginArray();
                serializer.serialize(writer, first, ctx, params);
                while (iterator.hasNext()) {
                    serializer.serialize(writer, iterator.next(), ctx, params);
                }
                writer.endArray();
            } else {
                // there is only one element, we write it directly
                serializer.serialize(writer, first, ctx, params);
            }

        } else {
            writer.beginArray();
            while (iterator.hasNext()) {
                serializer.serialize(writer, iterator.next(), ctx, params);
            }
            writer.endArray();
        }
    }
}