PartBodyConsumer.java

/*
 * PartBodyConsumer.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.io.IOException;

import org.simpleframework.transport.Cursor;
import org.simpleframework.util.buffer.Allocator;

/**
 * The <code>PartBodyConsumer</code> object is used to consume a part the
 * contents of a multipart body. This will consume the part and add it to a part
 * list, once the part has been consumed and added to the part list a terminal
 * token is consumed, which is a carriage return and line feed.
 * 
 * @author Niall Gallagher
 */
class PartBodyConsumer implements BodyConsumer {

    /**
     * This is the token that is consumed after the content body.
     */
    private static final byte[] LINE = { '\r', '\n' };

    /**
     * This is used to consume the content from the multipart upload.
     */
    private ContentConsumer content;

    /**
     * This is used to consume the final terminal token from the part.
     */
    private Consumer token;

    /**
     * Constructor for the <code>PartBodyConsumer</code> object. This is used to
     * create a consumer that reads the body of a part in a multipart request
     * body. The terminal token must be provided so that the end of the part
     * body can be determined.
     * 
     * @param allocator
     *            this is used to allocate the internal buffer
     * @param segment
     *            this represents the headers for the part body
     * @param boundary
     *            this is the message boundary for the body part
     */
    public PartBodyConsumer(Allocator allocator, Segment segment,
            byte[] boundary) {
        this(allocator, segment, new PartData(), boundary);
    }

    /**
     * Constructor for the <code>PartBodyConsumer</code> object. This is used to
     * create a consumer that reads the body of a part in a multipart request
     * body. The terminal token must be provided so that the end of the part
     * body can be determined.
     * 
     * @param allocator
     *            this is used to allocate the internal buffer
     * @param segment
     *            this represents the headers for the part body
     * @param series
     *            this is the part list that this body belongs in
     * @param boundary
     *            this is the message boundary for the body part
     */
    public PartBodyConsumer(Allocator allocator, Segment segment,
            PartSeries series, byte[] boundary) {
        this.content = new ContentConsumer(allocator, segment, series, boundary);
        this.token = new TokenConsumer(allocator, LINE);
    }

    /**
     * This is used to acquire the body that has been consumed. This will return
     * a body which can be used to read the content of the message, also if the
     * request is multipart upload then all of the parts are provided as
     * <code>Attachment</code> objects. Each part can then be read as an
     * individual message.
     * 
     * @return the body that has been consumed by this instance
     */
    @Override
    public Body getBody() {
        return this.content.getBody();
    }

    /**
     * This is used to consume the part body from the cursor. This initially
     * reads the body of the part, which represents the actual payload exposed
     * via the <code>Part</code> interface once the payload has been consumed
     * the terminal is consumed.
     * 
     * @param cursor
     *            this is the cursor to consume the body from
     */
    @Override
    public void consume(Cursor cursor) throws IOException {
        while (cursor.isReady()) {
            if (this.content.isFinished()) {
                if (this.token.isFinished()) {
                    break;
                }
                this.token.consume(cursor);
            } else {
                this.content.consume(cursor);
            }
        }
    }

    /**
     * This is used to determine whether the part body has been read from the
     * cursor successfully. In order to determine if all of the bytes have been
     * read successfully this will check to see of the terminal token had been
     * consumed.
     * 
     * @return true if the part body and terminal have been read
     */
    @Override
    public boolean isFinished() {
        return this.token.isFinished();
    }
}