net.glxn.qrgen.core.AbstractQRCode Maven / Gradle / Ivy

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package net.glxn.qrgen.core;

import com.google.zxing.EncodeHintType;
import com.google.zxing.Writer;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import net.glxn.qrgen.core.exception.QRGenerationException;
import net.glxn.qrgen.core.image.ImageType;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;

/**
 * QRCode generator. This is a simple class that is built on top of ZXING
 * 
 * Please take a look at their framework, as it has a lot of features. 
 This small project is just a wrapper that gives a
 * convenient interface to work with.
 * 
 */
public abstract class AbstractQRCode {

    protected final HashMap hints = new HashMap<>();

    protected Writer qrWriter;

    protected int width = 125;

    protected int height = 125;

    protected ImageType imageType = ImageType.PNG;

    /**
     * returns a {@link File} representation of the QR code. The file is set to be deleted on exit (i.e. {@link
     * File#deleteOnExit()}). If you want the file to live beyond the life of the jvm process, you should make a copy.
     *
     * @return qrcode as file
     */
    public abstract File file();

    /**
     * returns a {@link File} representation of the QR code. The file has the given name. The file is set to be deleted on exit
     * (i.e. {@link File#deleteOnExit()}). If you want the file to live beyond the life of the jvm process, you should
     * make a copy.
     *
     * @param name name of the created file
     * @return qrcode as file
     * @see #file()
     */
    public abstract File file(String name);

    /**
     * returns a {@link ByteArrayOutputStream} representation of the QR code
     *
     * @return qrcode as stream
     */
    public ByteArrayOutputStream stream() {
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        try {
            writeToStream(stream);
        } catch (Exception e) {
            throw new QRGenerationException("Failed to create QR image from text due to underlying exception", e);
        }

        return stream;
    }

    /**
     * writes a representation of the QR code to the supplied  {@link OutputStream}
     *
     * @param stream the {@link OutputStream} to write QR Code to
     */
    public void writeTo(OutputStream stream) {
        try {
            writeToStream(stream);
        } catch (Exception e) {
            throw new QRGenerationException("Failed to create QR image from text due to underlying exception", e);
        }
    }

    protected abstract void writeToStream(OutputStream stream) throws IOException, WriterException;

    protected BitMatrix createMatrix(String text) throws WriterException {
        return qrWriter.encode(text, com.google.zxing.BarcodeFormat.QR_CODE, width, height, hints);
    }

    protected File createTempFile() throws IOException {
        File file = File.createTempFile("QRCode", "." + imageType.toString().toLowerCase());
        file.deleteOnExit();
        return file;
    }

    protected File createTempFile(String name) throws IOException {
        File file = File.createTempFile(name, "." + imageType.toString().toLowerCase());
        file.deleteOnExit();
        return file;
    }

    public Writer getQrWriter() {
        return qrWriter;
    }

    public void setQrWriter(Writer qrWriter) {
        this.qrWriter = qrWriter;
    }
}