/*
 * PartData.java February 2007
 *
 * Copyright (C) 2007, Niall Gallagher <niallg@users.sf.net>
 *
 * 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.simpleframework.http.message;

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

import org.simpleframework.http.Part;
import org.simpleframework.util.KeyMap;

/**
 * The <code>PartData</code> object represents an ordered list of parts that
 * were uploaded within a HTTP entity body. This allows the parts to be iterated
 * over, or if required accessed by name. In order to access the
 * <code>Part</code> object by name it must have had a name within the
 * Content-Disposition header.
 * 
 * @author Niall Gallagher
 */
class PartData implements PartSeries {

    /**
     * This is the key map that is used to store the part objects.
     */
    private final KeyMap<Part> map;

    /**
     * This is the list of attachments for this part list object.
     */
    private final List<Part> list;

    /**
     * Constructor for the <code>PartData</code> object. This is used to create
     * an order list of parts that is used by the request to access the
     * individual parts uploaded with a HTTP body.
     */
    public PartData() {
        this.list = new ArrayList<Part>();
        this.map = new KeyMap<Part>();
    }

    /**
     * This is used to acquire the attachments associated with this list. If no
     * parts have been collected by this list then it will return an empty list.
     * The order of the parts in the list are the insertion order for
     * consistency.
     * 
     * @return this returns the parts collected in iteration order
     */
    @Override
    public List<Part> getParts() {
        return this.list;
    }

    /**
     * This is used to add a part to the list. The order the parts are added to
     * the list is the iteration order. If the part has a name that is not null
     * then it is added to an internal map using that name. This allows it to be
     * accesses by name at a later time.
     * 
     * @param part
     *            this is the part that is to be added to the list
     * 
     * @return returns true if the list has changed due to the add
     */
    @Override
    public boolean addPart(Part part) {
        String name = part.getName();

        if (name != null) {
            this.map.put(name, part);
        }
        return this.list.add(part);
    }

    /**
     * This method is used to acquire a <code>Part</code> from the list using a
     * known name for the part. This is a convenient way to access a part when
     * the name for the part is known.
     * 
     * @param name
     *            this is the name of the part to acquire
     * 
     * @return the named part or null if the part does not exist
     */
    @Override
    public Part getPart(String name) {
        return this.map.get(name);
    }
}