This is a code I used to encrypt a message entered by a user in a text box. Im wondering how to make a code like this, but instead, take an encrypted message, insert it in a new text box and turn it into a decrypted message.
private void btnDecryptActionPerformed(java.awt.event.ActionEvent evt) {
String origMessage;
String encMessage = "";
char tempChar;
int tempAscii;
origMessage = txtDecrypt.getText();
for (int i = 0; i < origMessage.length(); i = i + 1) {
tempChar = origMessage.charAt(i);
tempAscii = (int) tempChar;
tempAscii = tempAscii + 3;
tempChar = (char) tempAscii;
encMessage = encMessage + tempChar;
}
if (origMessage.length() < 30) {
fTxtEncrypt.setText(encMessage);
} else {
fTxtEncrypt.setText("Must be less than 30 characters...");
}
}
The Caesar cipher shifts each character by a certain number of characters. To decrypt this message, you have to shift them back by the same number of characters:
public static void main(String[] args) {
String encrypted = caesarCipher("message", 3);
String decrypted = caesarCipher(encrypted, -3);
System.out.println(encrypted); // phvvdjh
System.out.println(decrypted); // message
}
public static String caesarCipher(String source, int shift) {
StringBuilder target = new StringBuilder(source.length());
for (int i = 0; i < source.length(); i++) {
target.append((char) (source.charAt(i) + shift));
}
return target.toString();
}
For decrypting you need to do tempAscii - 3
Example :
public class Test {
public static void main(String args[]) throws Exception {
String origMessage = "Hello world";
String encMessage = encrypt(origMessage);
System.out.println("encrypt message :" + encMessage);
System.out.println("decrypt message :" + decrypt(encMessage));
}
static String decrypt(String encMessage) throws Exception {
return encryptOrDecrypt(encMessage, "decrypt");
}
static String encrypt(String encMessage) throws Exception {
return encryptOrDecrypt(encMessage, "encrypt");
}
private static String encryptOrDecrypt(String message, String type)
throws Exception {
char tempChar;
int tempAscii;
String resultMessage = "";
for (int i = 0; i < message.length(); i = i + 1) {
tempChar = message.charAt(i);
tempAscii = (int) tempChar;
if (type.equals("encrypt")) {
tempAscii = tempAscii + 3;
} else {
tempAscii = tempAscii - 3;
}
tempChar = (char) tempAscii;
resultMessage = resultMessage + tempChar;
}
if (message.length() < 30) {
return resultMessage;
} else {
throw new Exception("Must be less than 30 characters...");
}
}
}
Output:
encrypt message :Khoor#zruog
decrypt message :Hello world
I've been trying to work on this problem for a while now but to no avail. When I run the code I get this error message: incompatible types: edu.duke.StorageResource cannot be converted to java.lang.String on line String geneList = FMG.storeAll(dna);. Does this mean I'm trying to make edu.duke object work with a java.lang.String type object? What would we go about resolving this issue?
Here's my code so far:
package coursera_java_duke;
import java.io.*;
import edu.duke.FileResource;
import edu.duke.StorageResource;
import edu.duke.DirectoryResource;
public class FindMultiGenes5 {
public int findStopIndex(String dna, int index) {
int stop1 = dna.indexOf("TGA", index);
if (stop1 == -1 || (stop1 - index) % 3 != 0) {
stop1 = dna.length();
}
int stop2 = dna.indexOf("TAA", index);
if (stop2 == -1 || (stop2 - index) % 3 != 0) {
stop2 = dna.length();
}
int stop3 = dna.indexOf("TAG", index);
if (stop3 == -1 || (stop3 - index) % 3 != 0) {
stop3 = dna.length();
}
return Math.min(stop1, Math.min(stop2, stop3));
}
public StorageResource storeAll(String dna) {
//CATGTAATAGATGAATGACTGATAGATATGCTTGTATGCTATGAAAATGTGAAATGACCCAdna = "CATGTAATAGATGAATGACTGATAGATATGCTTGTATGCTATGAAAATGTGAAATGACCCA";
String geneAL = new String();
String sequence = dna.toUpperCase();
StorageResource store = new StorageResource();
int index = 0;
while (true) {
index = sequence.indexOf("ATG", index);
if (index == -1)
break;
int stop = findStopIndex(sequence, index + 3);
if (stop != sequence.length()) {
String gene = dna.substring(index, stop + 3);
store.add(gene);
//index = sequence.substring(index, stop + 3).length();
index = stop + 3; // start at the end of the stop codon
}else{ index = index + 3;
}
}
return store;//System.out.println(sequence);
}
public void testStorageFinder() {
DirectoryResource dr = new DirectoryResource();
StorageResource dnaStore = new StorageResource();
for (File f : dr.selectedFiles()) {
FileResource fr = new FileResource(f);
String s = fr.asString();
dnaStore = storeAll(s);
printGenes(dnaStore);
}
System.out.println("size = " + dnaStore.size());
}
public String readStrFromFile(){
FileResource readFile = new FileResource();
String DNA = readFile.asString();
//System.out.println("DNA: " + DNA);
return DNA;
}//end readStrFromFile() method;
public float calCGRatio(String gene){
gene = gene.toUpperCase();
int len = gene.length();
int CGCount = 0;
for(int i=0; i<len; i++){
if(gene.charAt(i) == 'C' || gene.charAt(i) == 'G')
CGCount++;
}//end for loop
System.out.println("CGCount " + CGCount + " Length: " + len + " Ratio: " + (float)CGCount/len);
return (float)CGCount/len;
}//end of calCGRatio() method;
public void printGenes(StorageResource sr){
//create a FindMultiGenesFile object FMG
FindMultiGenes5 FMG = new FindMultiGenes5();
//read a DNA sequence from file
String dna = FMG.readStrFromFile();
String geneList = FMG.storeAll(dna);
//store all genes into a document
StorageResource dnaStore = new StorageResource();
System.out.println("\n There are " + geneList.size() + " genes. ");
int longerthan60 = 0;
int CGGreaterthan35 = 0;
for(int i=0; i<geneList.size(); i++){
if(!dnaStore.contains(geneList.get(i)))
dnaStore.add(geneList.get(i));
if(geneList.get(i).length() > 60) longerthan60++;
if(FMG.calCGRatio(geneList.get(i)) > 0.35) CGGreaterthan35++;
}
System.out.println("dnaStore.size: " + dnaStore.size());
System.out.println("\n There are " + dnaStore.size() + " genes. ");
System.out.println("There are " + longerthan60 + " genes longer than 60.");
System.out.println("There are " + CGGreaterthan35 + " genes with CG ratio greater than 0.35.");
}//end main();
}
I found your post as I am also doing a similar course at Duke using those edu.duke libraries.
When I get that error message it is because I'm using the wrong method to access it.
Try FMD.data() to get an iterable of all of the gene strings.
I used lingpipe for sentence detection but I don't have any idea if there is a better tool. As far as I have understood, there is no way to compare two sentences and see if they mean the same thing.
Is there anyother good source where I can have a pre-built method for comparing two sentences and see if they are similar?
My requirement is as below:
String sent1 = "Mary and Meera are my classmates.";
String sent2 = "Meera and Mary are my classmates.";
String sent3 = "I am in Meera and Mary's class.";
// several sentences will be formed and basically what I need to do is
// this
boolean bothAreEqual = compareOf(sent1, sent2);
sop(bothAreEqual); // should print true
boolean bothAreEqual = compareOf(sent2, sent3);
sop(bothAreEqual);// should print true
How to test if the meaning of two sentences are the same: this would be a too open-ended question.
However, there are methods for comparing two sentences and see if they are similar. There are many possible definition for similarity that can be tested with pre-built methods.
See for example http://en.wikipedia.org/wiki/Levenshtein_distance
Distance between
'Mary and Meera are my classmates.'
and 'Meera and Mary are my classmates.':
6
Distance between
'Mary and Meera are my classmates.'
and 'Alice and Bobe are not my classmates.':
14
Distance between
'Mary and Meera are my classmates.'
and 'Some totally different sentence.':
29
code:
public class LevenshteinDistance {
private static int minimum(int a, int b, int c) {
return Math.min(Math.min(a, b), c);
}
public static int computeDistance(CharSequence str1,
CharSequence str2) {
int[][] distance = new int[str1.length() + 1][str2.length() + 1];
for (int i = 0; i <= str1.length(); i++){
distance[i][0] = i;
}
for (int j = 0; j <= str2.length(); j++){
distance[0][j] = j;
}
for (int i = 1; i <= str1.length(); i++){
for (int j = 1; j <= str2.length(); j++){
distance[i][j] = minimum(
distance[i - 1][j] + 1,
distance[i][j - 1] + 1,
distance[i - 1][j - 1]
+ ((str1.charAt(i - 1) == str2.charAt(j - 1)) ? 0 : 1));
}
}
int result = distance[str1.length()][str2.length()];
//log.debug("distance:"+result);
return result;
}
public static void main(String[] args) {
String sent1="Mary and Meera are my classmates.";
String sent2="Meera and Mary are my classmates.";
String sent3="Alice and Bobe are not my classmates.";
String sent4="Some totally different sentence.";
System.out.println("Distance between \n'"+sent1+"' \nand '"+sent2+"': \n"+computeDistance(sent1, sent2));
System.out.println("Distance between \n'"+sent1+"' \nand '"+sent3+"': \n"+computeDistance(sent1, sent3));
System.out.println("Distance between \n'"+sent1+"' \nand '"+sent4+"': \n"+computeDistance(sent1, sent4));
}
}
Here is wat i have come up with. this is just a substitute till i get to the real thing but it might be of some help to people out there..
package com.examples;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import com.aliasi.sentences.MedlineSentenceModel;
import com.aliasi.sentences.SentenceModel;
import com.aliasi.tokenizer.IndoEuropeanTokenizerFactory;
import com.aliasi.tokenizer.Tokenizer;
import com.aliasi.tokenizer.TokenizerFactory;
import com.aliasi.util.Files;
import com.sun.accessibility.internal.resources.accessibility;
public class SentenceWordAnalysisAndLevenshteinDistance {
private static int minimum(int a, int b, int c) {
return Math.min(Math.min(a, b), c);
}
public static int computeDistance(CharSequence str1, CharSequence str2) {
int[][] distance = new int[str1.length() + 1][str2.length() + 1];
for (int i = 0; i <= str1.length(); i++) {
distance[i][0] = i;
}
for (int j = 0; j <= str2.length(); j++) {
distance[0][j] = j;
}
for (int i = 1; i <= str1.length(); i++) {
for (int j = 1; j <= str2.length(); j++) {
distance[i][j] = minimum(
distance[i - 1][j] + 1,
distance[i][j - 1] + 1,
distance[i - 1][j - 1]
+ ((str1.charAt(i - 1) == str2.charAt(j - 1)) ? 0
: 1));
}
}
int result = distance[str1.length()][str2.length()];
return result;
}
static final TokenizerFactory TOKENIZER_FACTORY = IndoEuropeanTokenizerFactory.INSTANCE;
static final SentenceModel SENTENCE_MODEL = new MedlineSentenceModel();
public static void main(String[] args) {
try {
ArrayList<String> sentences = null;
sentences = new ArrayList<String>();
// Reading from text file
// sentences = readSentencesInFile("D:\\sam.txt");
// Giving sentences
// ArrayList<String> sentences = new ArrayList<String>();
sentences.add("Mary and Meera are my classmates.");
sentences.add("Mary and Meera are my classmates.");
sentences.add("Meera and Mary are my classmates.");
sentences.add("Alice and Bobe are not my classmates.");
sentences.add("Some totally different sentence.");
// Self-implemented
wordAnalyser(sentences);
// Internet referred
// levenshteinDistance(sentences);
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
private static ArrayList<String> readSentencesInFile(String path) {
ArrayList<String> sentencesList = new ArrayList<String>();
try {
System.out.println("Reading file from : " + path);
File file = new File(path);
String text = Files.readFromFile(file, "ISO-8859-1");
System.out.println("INPUT TEXT: ");
System.out.println(text);
List<String> tokenList = new ArrayList<String>();
List<String> whiteList = new ArrayList<String>();
Tokenizer tokenizer = TOKENIZER_FACTORY.tokenizer(
text.toCharArray(), 0, text.length());
tokenizer.tokenize(tokenList, whiteList);
System.out.println(tokenList.size() + " TOKENS");
System.out.println(whiteList.size() + " WHITESPACES");
String[] tokens = new String[tokenList.size()];
String[] whites = new String[whiteList.size()];
tokenList.toArray(tokens);
whiteList.toArray(whites);
int[] sentenceBoundaries = SENTENCE_MODEL.boundaryIndices(tokens,
whites);
System.out.println(sentenceBoundaries.length
+ " SENTENCE END TOKEN OFFSETS");
if (sentenceBoundaries.length < 1) {
System.out.println("No sentence boundaries found.");
return new ArrayList<String>();
}
int sentStartTok = 0;
int sentEndTok = 0;
for (int i = 0; i < sentenceBoundaries.length; ++i) {
sentEndTok = sentenceBoundaries[i];
System.out.println("SENTENCE " + (i + 1) + ": ");
StringBuffer sentenceString = new StringBuffer();
for (int j = sentStartTok; j <= sentEndTok; j++) {
sentenceString.append(tokens[j] + whites[j + 1]);
}
System.out.println(sentenceString.toString());
sentencesList.add(sentenceString.toString());
sentStartTok = sentEndTok + 1;
}
} catch (IOException e) {
// TODO: handle exception
e.printStackTrace();
}
return sentencesList;
}
private static void levenshteinDistance(ArrayList<String> sentences) {
System.out.println("\nLevenshteinDistance");
for (int i = 0; i < sentences.size(); i++) {
System.out.println("Distance between \n'" + sentences.get(0)
+ "' \nand '" + sentences.get(i) + "': \n"
+ computeDistance(sentences.get(0),
sentences.get(i)));
}
}
private static void wordAnalyser(ArrayList<String> sentences) {
System.out.println("No.of Sentences : " + sentences.size());
List<String> stopWordsList = getStopWords();
List<String> tokenList = new ArrayList<String>();
ArrayList<List<String>> filteredSentences = new ArrayList<List<String>>();
for (int i = 0; i < sentences.size(); i++) {
tokenList = new ArrayList<String>();
List<String> whiteList = new ArrayList<String>();
Tokenizer tokenizer = TOKENIZER_FACTORY.tokenizer(sentences.get(i)
.toCharArray(), 0, sentences.get(i).length());
tokenizer.tokenize(tokenList, whiteList);
System.out.print("Sentence " + (i + 1) + ": " + tokenList.size()
+ " TOKENS, ");
System.out.println(whiteList.size() + " WHITESPACES");
filteredSentences.add(filterStopWords(tokenList, stopWordsList));
}
for (int i = 0; i < sentences.size(); i++) {
System.out.println("\n" + (i + 1) + ". Comparing\n '"
+ sentences.get(0) + "' \nwith\n '" +
sentences.get(i)
+ "' : \n");
System.out.println(filteredSentences.get(0) + "\n and \n"
+ filteredSentences.get(i));
System.out.println("Percentage of similarity: "
+ calculateSimilarity(filteredSentences.get(0),
filteredSentences.get(i))
+ "%");
}
}
private static double calculateSimilarity(List<String> list1,
List<String> list2) {
int length1 = list1.size();
int length2 = list2.size();
int count1 = 0;
int count2 = 0;
double result1 = 0.0;
double result2 = 0.0;
int least, highest;
if (length2 > length1) {
least = length1;
highest = length2;
} else {
least = length2;
highest = length1;
}
// computing result1
for (String string1 : list1) {
if (list2.contains(string1))
count1++;
}
result1 = (count1 * 100) / length1;
// computing result2
for (String string2 : list2) {
if (list1.contains(string2))
count2++;
}
result2 = (count2 * 100) / length2;
double avg = (result1 + result2) / 2;
return avg;
}
private static List<String> getStopWords() {
String stopWordsString = ".,a,able,about,across,after,all,almost,also,am,among,an,and,any,are,as,at,be,because,been,but,by,can,cannot,could,dear,did,do,does,either,else,ever,every,for,from,get,got,had,has,have,he,her,hers,him,his,how,however,i,if,in,into,is,it,its,just,least,let,like,likely,may,me,might,most,must,my,neither,no,nor,not,of,off,often,on,only,or,other,our,own,rather,said,say,says,she,should,since,so,some,than,that,the,their,them,then,there,these,they,this,tis,to,too,twas,us,wants,was,we,were,what,when,where,which,while,who,whom,why,will,with,would,yet,you,your";
List<String> stopWordsList = new ArrayList<String>();
List<String> stopWordTokenList = new ArrayList<String>();
List<String> whiteList = new ArrayList<String>();
Tokenizer tokenizer = TOKENIZER_FACTORY.tokenizer(
stopWordsString.toCharArray(), 0, stopWordsString.length());
tokenizer.tokenize(stopWordTokenList, whiteList);
for (int i = 0; i < stopWordTokenList.size(); i++) {
// System.out.println((i + 1) + ":" + tokenList.get(i));
if (!stopWordTokenList.get(i).equals(",")) {
stopWordsList.add(stopWordTokenList.get(i));
}
}
System.out.println("No.of stop words: " + stopWordsList.size());
return stopWordsList;
}
private static List<String> filterStopWords(List<String> tokenList,
List<String> stopWordsList) {
List<String> filteredSentenceWords = new ArrayList<String>();
for (String sentenceToken : tokenList) {
if (!stopWordsList.contains(sentenceToken)) {
filteredSentenceWords.add(sentenceToken);
}
}
return filteredSentenceWords;
}
}
I've been trying to convert a PHP code to Java, but its not working as intended. I get an error in the loop with "String index out of range" after a few runs on char nextchar = inprogresskey.charAt(ranpos);
The PHP code is:
function munge($address)
{
$address = strtolower($address);
$coded = "";
$unmixedkey = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.#";
$inprogresskey = $unmixedkey;
$mixedkey="";
$unshuffled = strlen($unmixedkey);
for ($i = 0; $i <= strlen($unmixedkey); $i++)
{
$ranpos = rand(0,$unshuffled-1);
$nextchar = $inprogresskey{$ranpos};
$mixedkey .= $nextchar;
$before = substr($inprogresskey,0,$ranpos);
$after = substr($inprogresskey,$ranpos+1,$unshuffled-($ranpos+1));
$inprogresskey = $before.''.$after;
$unshuffled -= 1;
}
$cipher = $mixedkey;
$shift = strlen($address);
for ($j=0; $j<strlen($address); $j++)
{
if (strpos($cipher,$address{$j}) == -1 )
{
$chr = $address{$j};
$coded .= $address{$j};
}
else
{
$chr = (strpos($cipher,$address{$j}) + $shift) % strlen($cipher);
$coded .= $cipher{$chr};
}
}
$txt = "<script type=\"text/javascript\" language=\"javascript\">\n";
$txt .= "\ncoded = \"" . $coded . "\"\n" .
" key = \"".$cipher."\"\n".
" shift=coded.length\n".
" link=\"\"\n".
" for (i=0; i<coded.length; i++) {\n" .
" if (key.indexOf(coded.charAt(i))==-1) {\n" .
" ltr = coded.charAt(i)\n" .
" link += (ltr)\n" .
" }\n" .
" else { \n".
" ltr = (key.indexOf(coded.charAt(i))-
shift+key.length) % key.length\n".
" link += (key.charAt(ltr))\n".
" }\n".
" }\n".
"document.write(\"<a href='mailto:\"+link+\"'>\"+link+\"</a>\")\n" .
"\n".
"//-"."->\n" .
"<" . "/script><noscript>N/A" .
"<"."/noscript>";
return $txt;
}
And my Java code is:
private String encryptEmail(String email)
{
String address = email.toLowerCase();
String coded = "";
String unmixedkey = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789.#";
String inprogresskey = unmixedkey;
String mixedkey = "";
int unshuffled = unmixedkey.length();
for (int i = 0; i <= unmixedkey.length(); i++) {
Random random = new Random();
int ranpos = random.nextInt(unshuffled - 1);
char nextchar = inprogresskey.charAt(ranpos);
mixedkey += nextchar;
String before = StringUtils.substring(inprogresskey, 0, ranpos);
String after = StringUtils.substring(inprogresskey, ranpos + 1, unshuffled - (ranpos + 1));
inprogresskey = before + "" + after;
unshuffled -= 1;
}
String cipher = mixedkey;
int shift = address.length();
for (int j = 0; j < address.length(); j++) {
int chr = -1;
if (StringUtils.indexOf(cipher, address.substring(j - 1, j)) == -1) {
coded += address.charAt(j);
} else {
chr = (cipher.charAt(j + shift)) % cipher.length();
coded += cipher.charAt(chr);
}
}
StringBuilder sb = new StringBuilder();
sb.append("<script type=\"text/javascript\">\n");
sb.append("var coded = \"" + coded + "\";\n");
sb.append("var key = \"" + cipher + "\";\n");
sb.append("var shift = coded.length;\n");
sb.append("var link = \"\";\n");
sb.append("for (i = 0; i < coded.length; i++) {\n");
sb.append(" if (key.indexOf(coded.charAt(i))==-1) {\n");
sb.append(" ltr = coded.charAt(i);\n");
sb.append(" link += (ltr);\n");
sb.append(" }\n");
sb.append(" else {\n");
sb.append(" ltr = (key.indexOf(coded.charAt(i))-shift+key.length) % key.length;\n");
sb.append(" link += (key.charAt(ltr));\n");
sb.append(" }");
sb.append("}");
sb.append("document.write(\"<a rel='nofollow' href='mailto:\" + link + \"'>\" + link + \"</a>\");\n");
sb.append("</script>");
return sb.toString();
}
Am I missing out on some functions (charAt, indexOf)?
Thanks
int ranpos = random.nextInt(unshuffled - 1);
atlast ranpos = 1
and you are doing nextInt(1 - 1)
char nextchar = inprogresskey.charAt(ranpos)
that's way above line gives you error
what you need to do is:
update your for loop for (int i = 0; i < unmixedkey.length(); i++)
and inside the loop add the below line of code
if(unshuffled==1)
{
ranpos = 1;
}
else {
ranpos = random.nextInt(unshuffled - 1);
}
The below is fully functional for loop code.
for (int i = 0; i < unmixedkey.length(); i++) {
Random random = new Random();
int ranpos=0;
if(unshuffled==1)
{
ranpos = 1;
}else{
ranpos = random.nextInt(unshuffled - 1);
}
char nextchar = inprogresskey.charAt(ranpos);
mixedkey += nextchar;
String before = StringUtils.substring(inprogresskey, 0, ranpos);
String after = StringUtils.substring(inprogresskey, ranpos + 1, unshuffled - (ranpos + 1));
inprogresskey = before + "" + after;
unshuffled -= 1;
}
I suspect that unshuffled is equal to 0 on the last time through the loop, and so charAt(-1) is failing.
You should take a look at Java IDEs like Eclipse and the debugger. Adding breakpoints will enable you to step through the code as it runs, and see the values of all variables, which would be the quickest way of solving this sort of issue in future.