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package solid.collectors;

import java.util.ArrayList;
import java.util.List;

import solid.functions.Func1;

public class ToArrayList {

    private static final Func1 TO_ARRAY_LIST = toArrayList(0);

    /**
     * Returns a method that can be used with {@link solid.stream.Stream#collect(Func1)}
     * to convert a stream into a {@link ArrayList}.
     *
     * @param  a type of {@link ArrayList} items.
     * @return a method that converts an iterable into {@link ArrayList}.
     */
    public static  Func1, ArrayList> toArrayList() {
        return TO_ARRAY_LIST;
    }

    /**
     * Returns a method that can be used with {@link solid.stream.Stream#collect(Func1)}
     * to convert a stream into a {@link List}.
     * 
     * Use this method instead of {@link #toArrayList()} for better performance on
     * streams that can have more than 12 items.
     *
     * @param              a type of {@link List} items.
     * @param initialCapacity initial capacity of the list.
     * @return a method that converts an iterable into {@link List}.
     */
    public static  Func1, ArrayList> toArrayList(final int initialCapacity) {
        return new Func1, ArrayList>() {
            @Override
            public ArrayList call(Iterable iterable) {
                ArrayList list = new ArrayList<>(initialCapacity);
                for (T value : iterable)
                    list.add(value);
                return list;
            }
        };
    }
}