SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package net.multiphasicapps.collections;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Deque;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 * This is a class which provides a multiple {@link Deque} compatible interface
 * where every element within the queue is unique as if it were a member of
 * a {@link Set}. Note that the subdeques can be given elements that are shared
 * in multiple deques.
 *
 * In the returned {@link Deque}, elements which are removed will be removed
 * from the other {@link Deque}s. As such, clearing of one {@link Deque} may
 * result in other ones getting smaller in size.
 *
 * {@code null} elements are not permitted.
 *
 * This class is not thread safe.
 *
 * @param <V> The type of value to store in the dequeues.
 * @since 2016/09/03
 */
public class MultiSetDeque<V>
{
    /** Sub-queue list. */
    private final List<__Sub__<V>> _subs =
        new ArrayList<>();
    
    /** The global set of added elements. */
    final Set<V> _global =
        new HashSet<>();
    
    /**
     * Clears the multi-set deque and every sub-deque so that all are empty.
     *
     * @since 2017/03/25
     */
    public final void clear()
    {
        // Clear the global set
        this._global.clear();
        
        // And all the subsets
        for (__Sub__<V> s : this._subs)
            s.__clear();
    }
    
    /**
     * Checks if the any of the sub-deques contain the specified element.
     *
     * @param __v The element to check.
     * @return {@code true} if the element is any in deque.
     * @since 2017/04/25
     */
    public final boolean contains(V __v)
    {
        return this._global.contains(__v);
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/03/25
     */
    @Override
    public final boolean equals(Object __o)
    {
        if (!(__o instanceof MultiSetDeque))
            return false;
        
        return this._subs.equals(((MultiSetDeque<?>)__o)._subs);
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/03/25
     */
    @Override
    public final int hashCode()
    {
        return this._subs.hashCode();
    }
    
    /**
     * Removes the given element from any of the sub-{@link Deque}s that are
     * a part of the multi-set.
     *
     * @param __v The value to remove.
     * @return {@code true} if it was in any {@link Deque}.
     * @since 2016/09/03
     */
    public final boolean remove(V __v)
    {
        // Null will never be in this deque
        if (__v == null)
            return false;
        
        // If not in the global set then it will not be in any deque
        Set<V> global = this._global;
        if (!global.contains(__v))
            return false;
        
        // Remove in all
        List<__Sub__<V>> subs = this._subs;
        int n = subs.size();
        boolean rv = false;
        for (int i = 0; i < n; i++)
            rv |= subs.get(i).__remove(__v);
        
        // Remove from the global set because it will be no sub-deque
        global.remove(__v);
        
        // Was it removed?
        return rv;
    }
    
    /**
     * Returns a new sub-{@link Deque} which acts as part of the multi-deque.
     *
     * @return A new deque which shares the set restrictions.
     * @since 2016/09/03
     */
    public final Deque<V> subDeque()
    {
        return this.subDeque(Integer.MAX_VALUE);
    }
    
    /**
     * Returns a new sub-{@link Deque} which acts as part of the multi-deque
     * which is initialized using the given collection.
     *
     * @param __c The collection to add to the resulting {@link Deque}.
     * @return A new deque which shares the set restrictions.
     * @throws NullPointerException On null arguments.
     * @since 2016/09/15
     */
    public final Deque<V> subDeque(Collection<V> __c)
        throws NullPointerException
    {
        // Check
        if (__c == null)
            throw new NullPointerException("NARG");
        
        // Create
        Deque<V> rv = this.subDeque();
        rv.addAll(__c);
        return rv;
    }
    
    /**
     * Returns a new sub-{@link Deque} which acts as part of the multi-deque
     * which is limited to the given number of elements.
     *
     * @param __l The number of elements to limit to.
     * @return A new deque which shares the set restrictions.
     * @throws IllegalArgumentException If the limit is zero or negative.
     * @since 2016/09/03
     */
    public final Deque<V> subDeque(int __l)
        throws IllegalArgumentException
    {
        /* {@squirreljme.error AC05 The sub-deque limit is zero or negative.} */
        if (__l <= 0)
            throw new IllegalArgumentException("AC05");
        
        // Create it
        __Sub__<V> rv = new __Sub__<>(this, __l);
        this._subs.add(rv);
        return rv;
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/03/25
     */
    @Override
    public final String toString()
    {
        return this._subs.toString();
    }
}