com.octo.captcha.image.ImageCaptcha Maven / Gradle / Ivy

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/*
 * JCaptcha, the open source java framework for captcha definition and integration
 * Copyright (c)  2007 jcaptcha.net. All Rights Reserved.
 * See the LICENSE.txt file distributed with this package.
 */

package com.octo.captcha.image;

import com.octo.captcha.Captcha;

import javax.imageio.ImageIO;
import javax.imageio.stream.MemoryCacheImageInputStream;
import javax.imageio.stream.MemoryCacheImageOutputStream;
import java.awt.image.BufferedImage;
import java.io.IOException;

/**
 * 
 * String question about a BufferedImage challenge. Abstract.
 * 
 * 
 * @author Marc-Antoine Garrigue
 * @version 1.0
 */
public abstract class ImageCaptcha implements Captcha {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	private Boolean hasChallengeBeenCalled = Boolean.FALSE;

	protected String question;
	protected String response;
	// protected String textChallenge;

	protected transient BufferedImage challenge;

	protected ImageCaptcha(String question, BufferedImage challenge) {
		this.challenge = challenge;
		this.question = question;
	}

	protected ImageCaptcha(String question, String response, BufferedImage challenge) {
		this.challenge = challenge;

		this.question = question;
		this.response = response;
	}

	/**
	 * Accessor captcha question
	 * 
	 * @return the question
	 */
	public final String getQuestion() {
		return question;
	}

	public final String getResponse() {
		return response;
	}

	public final String getTextChallenge() {
		return response;
	}

	/**
	 * @return the challenge
	 */
	public final Object getChallenge() {
		return getImageChallenge();
	}

	/**
	 * @return the image challenge
	 */
	public final BufferedImage getImageChallenge() {
		hasChallengeBeenCalled = Boolean.TRUE;
		return challenge;
	}

	/**
	 * Dispose the challenge, once this method is call the getChallenge method
	 * will return null.

	 * It has been added for technical reasons : a captcha is always used in a
	 * two step fashion

	 * First submit the challenge, and then wait until the response arrives.

	 * It had been asked to have a method to dispose the challenge that is no
	 * longer used after being dipslayed. So here it is!
	 */
	public final void disposeChallenge() {
		this.challenge = null;
	}

	/**
	 * This method should return true if the getChalenge method has been called
	 * (has been added in order to properly manage the captcha state.
	 * 
	 * @return true if getChallenge has been called false otherwise.
	 */
	public Boolean hasGetChalengeBeenCalled() {
		return hasChallengeBeenCalled;
	}

	/**
	 * This method have to be implemented in order to serialize the image
	 * challenge to JPEG format
	 * 
	 * @param out
	 *            The target outputStream in which the captcha will be
	 *            serialized
	 * @throws IOException
	 */
	private void writeObject(java.io.ObjectOutputStream out) throws IOException {

		// Serialize captcha fields with defaut method
		out.defaultWriteObject();

		// If the challenge has not been disposed
		if (this.challenge != null) {
			// use png encoding
			ImageIO.write(this.challenge, "png", new MemoryCacheImageOutputStream(out));
		}
	}

	/**
	 * This method have to be implemented in order to unserialize the image
	 * challenge from JPEG format
	 * 
	 * @param in
	 *            The source inputStream from which the captcha will be
	 *            unserialized
	 * @throws IOException
	 * @throws ClassNotFoundException
	 */
	private void readObject(java.io.ObjectInputStream in) throws IOException, ClassNotFoundException {

		// UnSerialize captcha fields with default method
		in.defaultReadObject();

		try {

			this.challenge = ImageIO.read(new MemoryCacheImageInputStream(in));
		}
		catch (IOException e) {
			if (!hasChallengeBeenCalled.booleanValue()) {
				// If the getChallenge method has not been called the challenge
				// should be available for unmarhslling.
				// In this case, the thrown Exception is not related to the
				// dispose status
				throw e;
			}
		}
	}
}