/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * 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.android.dx.rop.type;

/**
 * List of {@link Type} instances (or of things that contain types).
 */
public interface TypeList {
    /**
     * Returns whether this instance is mutable. Note that the
     * <code>TypeList</code> interface itself doesn't provide any
     * means of mutation, but that doesn't mean that there isn't an
     * extra-interface way of mutating an instance.
     * 
     * @return <code>true</code> if this instance is mutable or
     * <code>false</code> if it is immutable
     */
    public boolean isMutable();
    
    /**
     * Gets the size of this list.
     *
     * @return >= 0; the size
     */
    public int size();

    /**
     * Gets the indicated element. It is an error to call this with the
     * index for an element which was never set; if you do that, this
     * will throw <code>NullPointerException</code>.
     *
     * @param n >= 0, < size(); which element
     * @return non-null; the indicated element
     */
    public Type getType(int n);

    /**
     * Gets the number of 32-bit words required to hold instances of
     * all the elements of this list. This is a sum of the widths (categories)
     * of all the elements.
     * 
     * @return >= 0; the required number of words
     */
    public int getWordCount();

    /**
     * Returns a new instance which is identical to this one, except that
     * the given item is appended to the end and it is guaranteed to be
     * immutable.
     * 
     * @param type non-null; item to append
     * @return non-null; an appropriately-constructed instance
     */
    public TypeList withAddedType(Type type);
}