PassPhraseGenerator.java

/* Copyright (c) 2012 Michael Macnair
 * 
 * The MIT License
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package app.randgen.backend;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;

import android.app.Activity;
import android.content.res.AssetManager;
import android.widget.EditText;
import android.widget.Toast;
import app.randgen.randomMain;

/**
 * A RandomGenerator that produces pass phrases
 */
public class PassPhraseGenerator extends RandomGenerator {
	/* {author=Michael Macnair} */

	/**
	 * the number of words in the phrase
	 */
	protected int numWords = 4;

	protected String[] dict;

	@Override
	public String getDescription() {
		return "Produces pass phrases from a dictionary, all words have the same (uniform) probability";
	}

	@Override
	public String getName() {
		return "Pass Phrase";
	}

	@Override
	public String getNext() {
		if (numWords < 1)
			return "Parameters not set";// TODO: set for R.string

		if (dict == null) {
			try {
				initDict();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				return "Could not initialise dictionary!";
			}
		}

		String phrase = "";
		int wordIdx;
		for (int i = 0; i < numWords; i++) {
			wordIdx = this.generator.nextInt(dict.length);
			phrase = phrase + " " + dict[wordIdx];
		}
		return phrase + "\n";
	}

	@Override
	public int getParamsLayoutID() {
		return app.randgen.R.id.passPhraseParams;
	}

	@Override
	public boolean setParameters(final Activity myActivity) {
		try {
			EditText edit = (EditText) myActivity
					.findViewById(app.randgen.R.id.passPhraseWords);
			numWords = Integer.parseInt(edit.getText().toString());
			if (numWords < 1) {
				throw new Exception("Passphrase must have at least one word.");
			}
			return true;
		} catch (Exception e) {
			Toast error = Toast.makeText(myActivity,
					app.randgen.R.string.paramError, Toast.LENGTH_SHORT);
			error.show();
			return false;
		}
	}

	private void initDict() throws IOException {
		ArrayList<String> dictList = new ArrayList<String>();

		AssetManager am = randomMain.getInstance().getAssets();

		InputStream is = null;
		InputStreamReader isr = null;
		BufferedReader br = null;
		try {
			is = am.open("british-english");
			isr = new InputStreamReader(is);
			br = new BufferedReader(isr);

			// Slurp the dictionary into the lines list
			String contents = br.readLine();
			int i = 0;
			while (contents != null) {
				dictList.add(contents);
				i = i + 1;
				contents = br.readLine();
			}
		} catch (IOException e) {
			throw e;
		} finally {
			br.close();
			isr.close();
			is.close();
		}

		// Convert dictList into array
		dict = new String[dictList.size()];
		dictList.toArray(dict);
	}
}