Reader.java

/*
 * Copyright 2007 ZXing authors
 *
 * 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.google.zxing;

import java.util.Map;

/**
 * Implementations of this interface can decode an image of a barcode in some
 * format into the String it encodes. For example,
 * {@link com.google.zxing.qrcode.QRCodeReader} can decode a QR code. The
 * decoder may optionally receive hints from the caller which may help it decode
 * more quickly or accurately.
 * 
 * See {@link com.google.zxing.MultiFormatReader}, which attempts to determine
 * what barcode format is present within the image as well, and then decodes it
 * accordingly.
 * 
 * @author Sean Owen
 * @author dswitkin@google.com (Daniel Switkin)
 */
public interface Reader {

	/**
	 * Locates and decodes a barcode in some format within an image.
	 * 
	 * @param image
	 *            image of barcode to decode
	 * @return String which the barcode encodes
	 * @throws NotFoundException
	 *             if no potential barcode is found
	 * @throws ChecksumException
	 *             if a potential barcode is found but does not pass its
	 *             checksum
	 * @throws FormatException
	 *             if a potential barcode is found but format is invalid
	 */
	Result decode(BinaryBitmap image) throws NotFoundException,
			ChecksumException, FormatException;

	/**
	 * Locates and decodes a barcode in some format within an image. This method
	 * also accepts hints, each possibly associated to some data, which may help
	 * the implementation decode.
	 * 
	 * @param image
	 *            image of barcode to decode
	 * @param hints
	 *            passed as a {@link java.util.Map} from
	 *            {@link com.google.zxing.DecodeHintType} to arbitrary data. The
	 *            meaning of the data depends upon the hint type. The
	 *            implementation may or may not do anything with these hints.
	 * @return String which the barcode encodes
	 * @throws NotFoundException
	 *             if no potential barcode is found
	 * @throws ChecksumException
	 *             if a potential barcode is found but does not pass its
	 *             checksum
	 * @throws FormatException
	 *             if a potential barcode is found but format is invalid
	 */
	Result decode(BinaryBitmap image, Map<DecodeHintType, ?> hints)
			throws NotFoundException, ChecksumException, FormatException;

	/**
	 * Resets any internal state the implementation has after a decode, to
	 * prepare it for reuse.
	 */
	void reset();

}