com.gs.collections.impl.list.fixed.DoubletonList Maven / Gradle / Ivy

/*
 * Copyright 2012 Goldman Sachs.
 *
 * 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.gs.collections.impl.list.fixed;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;

import com.gs.collections.api.block.procedure.Procedure;
import com.gs.collections.api.block.procedure.Procedure2;
import com.gs.collections.api.block.procedure.primitive.ObjectIntProcedure;
import com.gs.collections.impl.block.factory.Comparators;
import net.jcip.annotations.NotThreadSafe;

/**
 * A DoubletonList is a two-element memory efficient List.  It is created by calling Lists.fixedSize.of(one, two).
 */
@NotThreadSafe
final class DoubletonList
        extends AbstractMemoryEfficientMutableList
        implements Externalizable
{
    private static final long serialVersionUID = 1L;

    private T element1;
    private T element2;

    @SuppressWarnings("UnusedDeclaration")
    public DoubletonList()
    {
        // For Externalizable use only
    }

    DoubletonList(T obj1, T obj2)
    {
        this.element1 = obj1;
        this.element2 = obj2;
    }

    @Override
    public TripletonList with(T value)
    {
        return new TripletonList(this.element1, this.element2, value);
    }

    // Weird implementation of clone() is ok on final classes

    @Override
    public DoubletonList clone()
    {
        return new DoubletonList(this.element1, this.element2);
    }

    @Override
    public T getFirst()
    {
        return this.element1;
    }

    @Override
    public T getLast()
    {
        return this.element2;
    }

    public int size()
    {
        return 2;
    }

    public T get(int index)
    {
        switch (index)
        {
            case 0:
                return this.element1;
            case 1:
                return this.element2;
            default:
                throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + this.size());
        }
    }

    @Override
    public boolean contains(Object obj)
    {
        return Comparators.nullSafeEquals(obj, this.element1) || Comparators.nullSafeEquals(obj, this.element2);
    }

    /**
     * set is implemented purely to allow the List to be sorted, not because this List should be considered mutable.
     */
    public T set(int index, T element)
    {
        switch (index)
        {
            case 0:
                T previousElement1 = this.element1;
                this.element1 = element;
                return previousElement1;
            case 1:
                T previousElement2 = this.element2;
                this.element2 = element;
                return previousElement2;
            default:
                throw new IndexOutOfBoundsException("Index: " + index + ", Size: " + this.size());
        }
    }

    @Override
    public void forEach(Procedure procedure)
    {
        procedure.value(this.element1);
        procedure.value(this.element2);
    }

    @Override
    public void forEachWithIndex(ObjectIntProcedure objectIntProcedure)
    {
        objectIntProcedure.value(this.element1, 0);
        objectIntProcedure.value(this.element2, 1);
    }

    @Override
    public  void forEachWith(Procedure2 procedure, P parameter)
    {
        procedure.value(this.element1, parameter);
        procedure.value(this.element2, parameter);
    }

    public void writeExternal(ObjectOutput out) throws IOException
    {
        out.writeObject(this.element1);
        out.writeObject(this.element2);
    }

    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
    {
        this.element1 = (T) in.readObject();
        this.element2 = (T) in.readObject();
    }
}