org.tellervo.desktop.util.labels.LabBarcode.java Source code

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Here is the source code for org.tellervo.desktop.util.labels.LabBarcode.java

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/*******************************************************************************
 * Copyright (C) 2010 Lucas Madar and Peter Brewer
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * Contributors:
 *     Lucas Madar
 *     Peter Brewer
 ******************************************************************************/
package org.tellervo.desktop.util.labels;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.UUID;

import org.tellervo.desktop.util.Base64;

import com.lowagie.text.Font;
import com.lowagie.text.FontFactory;
import com.lowagie.text.pdf.Barcode;
import com.lowagie.text.pdf.Barcode128;

public class LabBarcode extends Barcode128 {

    /**
     * An enum representing the type of this barcode
     * 
     * @author Lucas Madar
     */
    public static enum Type {
        SAMPLE('S'), BOX('B'), SERIES('Z');

        /** The character we prepend to the UUID */
        private char charVal;

        Type(char c) {
            charVal = c;
        }

        public char getPrefix() {
            return charVal;
        }

        public static Type valueOf(char c) {
            for (Type type : values()) {
                if (type.charVal == c)
                    return type;
            }

            throw new IllegalArgumentException("Invalid type");
        }
    }

    /** The font we use to label the barcode */
    private static Font barcodeFont = FontFactory.getFont(FontFactory.COURIER);

    /**
     * Construct a new Lab Barcode representing a given UUID and UUID type
     * 
     * @param uuidType One of LabBarcode.Type
     * @param uuid The UUID to encode
     */
    public LabBarcode(Type uuidType, UUID uuid) {
        super();

        setCode(encode(uuidType, uuid));
        setAltText(uuidType + " " + uuid.toString());
        setCodeType(Barcode.CODE128);
        setFont(barcodeFont.getBaseFont());
    }

    /**
     * Encode a UUID and Type into base64
     * @param uuidType
     * @param uuid
     * @returns a string representing the base64 uuid
     */
    public static String encode(Type uuidType, UUID uuid) {
        // convert the uuid into a raw byte array
        ByteArrayOutputStream bbis = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(bbis);

        String b64enc;
        try {
            dos.writeByte((byte) uuidType.getPrefix());
            dos.writeByte((byte) ':');

            // start with high bits... is this proper?
            dos.writeLong(uuid.getMostSignificantBits());
            dos.writeLong(uuid.getLeastSignificantBits());

            b64enc = Base64.encodeBytes(bbis.toByteArray());
        } catch (IOException e) {
            // this should never happen, since it's a ByteArrayOutputStream
            throw new RuntimeException(e);
        }

        return b64enc;
    }

    /**
     * Silly class for a return value when decoding lab barcodes
     * @author Lucas Madar
     */
    public static class DecodedBarcode {
        public Type uuidType;
        public UUID uuid;
    }

    /**
     * Decodes an encoded barcode
     * 
     * @param b64enc
     * @return A decoded barcode structure
     */
    public static DecodedBarcode decode(String b64enc) {
        byte[] bytes;

        try {
            bytes = Base64.decode(b64enc);
        } catch (IOException e) {
            throw new IllegalArgumentException("Invalid barcode value (not base64)");
        }

        DataInputStream dis = new DataInputStream(new ByteArrayInputStream(bytes));
        try {
            char type = (char) dis.readByte();
            char colon = (char) dis.readByte();
            long msb = dis.readLong();
            long lsb = dis.readLong();

            if (colon != ':')
                throw new IllegalArgumentException("Barcode is not a Tellervo barcode (invalid format)");

            DecodedBarcode barcode = new DecodedBarcode();

            // load uuid
            barcode.uuid = new UUID(msb, lsb);
            try {
                barcode.uuidType = Type.valueOf(type);
            } catch (IllegalArgumentException iae) {
                throw new IllegalArgumentException("Invalid barcode type: " + type);
            }

            return barcode;
        } catch (IOException e) {
            throw new IllegalArgumentException("Barcode is not a Tellervo barcode");
        }
    }
}