I'm learning to program in Java using BlueJ and am making an exercise. However at the moment I'm completely stuck.

This is the class I'm working on with the relevant methods:





public String generateResponse(HashSet words)
{
Iterator it = words.iterator();
while(it.hasNext()) {
String word = it.next();

String response = responseMap.get(word);
if(response != null) {
return response;
}
}
return pickDefaultResponse();
}

private void fillResponseMap()
{
responseMap.put(crash,
"Well, it never crashes on our system. It must have something\n" +
"to do with your system. Tell me more about your configuration.");
responseMap.put("crashes",
"Well, it never crashes on our system. It must have something\n" +
"to do with your system. Tell me more about your configuration.");
responseMap.put("slow",
"I think this has to do with your hardware. Upgrading your processor\n" +
"should solve all performance problems. Have you got a problem with\n" +
"our software?");
responseMap.put("performance",
"Performance was quite adequate in all our tests. Are you running\n" +
"any other processes in the background?");
responseMap.put("bug",
"Well, you know, all software has some bugs. But our software engineers\n" +
"are working very hard to fix them. Can you describe the problem a bit\n" +
"further?");
responseMap.put("buggy",
"Well, you know, all software has some bugs. But our software engineers\n" +
"are working very hard to fix them. Can you describe the problem a bit\n" +
"further?");
responseMap.put("windows",
"This is a known bug to do with the Windows operating system. Please\n" +
"report it to Microsoft. There is nothing we can do about this.");
responseMap.put("macintosh",
"This is a known bug to do with the Mac operating system. Please\n" +
"report it to Apple. There is nothing we can do about this.");
responseMap.put("expensive",
"The cost of our product is quite competitive. Have you looked around\n" +
"and really compared our features?");
responseMap.put("installation",
"The installation is really quite straight forward. We have tons of\n" +
"wizards that do all the work for you. Have you read the installation\n" +
"instructions?");
responseMap.put("memory",
"If you read the system requirements carefully, you will see that the\n" +
"specified memory requirements are 1.5 giga byte. You really should\n" +
"upgrade your memory. Anything else you want to know?");
responseMap.put("linux",
"We take Linux support very seriously. But there are some problems.\n" +
"Most have to do with incompatible glibc versions. Can you be a bit\n" +
"more precise?");
responseMap.put("bluej",
"Ahhh, BlueJ, yes. We tried to buy out those guys long ago, but\n" +
"they simply won't sell... Stubborn people they are. Nothing we can\n" +
"do about it, I'm afraid.");
}

private void fillDefaultResponses()
{
defaultResponses.add("That sounds odd. Could you describe that problem in more detail?");
defaultResponses.add("No other customer has ever complained about this before. \n" +
"What is your system configuration?");
defaultResponses.add("That sounds interesting. Tell me more...");
defaultResponses.add("I need a bit more information on that.");
defaultResponses.add("Have you checked that you do not have a dll conflict?");
defaultResponses.add("That is explained in the manual. Have you read the manual?");
defaultResponses.add("Your description is a bit wishy-washy. Have you got an expert\n" +
"there with you who could describe this more precisely?");
defaultResponses.add("That's not a bug, it's a feature!");
defaultResponses.add("Could you elaborate on that?");
}

/**
* Randomly select and return one of the default responses.
* @return A random default response
*/
private String pickDefaultResponse()
{
// Pick a random number for the index in the default response list.
// The number will be between 0 (inclusive) and the size of the list (exclusive).
int index = randomGenerator.nextInt(defaultResponses.size());
return defaultResponses.get(index);
}
}


So basically, I type a sentence, it automatically controls if any of the words in the sentence correspond to one of the responseMaps and then it prints that one.
Now the exercise is that I have to make it so that it also detects synonyms or similar words without making extra response maps. Basically, I should be able to merge the Crash and Crashes response map. I have to do this by assigning multiple values to a String I think.
So I've made this:
String[] crash = { "crash", "crashes", "freeze" };
I don't know what to do with it, or even how to use it correctly. Does anybody have any suggestions?

Formatted and highlighted version of the code to help other people solve the issue:

public String generateResponse(HashSet words) {    Iterator it = words.iterator();    while (it.hasNext()) {        String word = it.next();        String response = responseMap.get(word);        if (response != null) {            return response;        }    }    return pickDefaultResponse();}private void fillResponseMap() {    responseMap.put(crash,            "Well, it never crashes on our system. It must have something\n"            + "to do with your system. Tell me more about your configuration.");    responseMap.put("crashes",            "Well, it never crashes on our system. It must have something\n"            + "to do with your system. Tell me more about your configuration.");    responseMap.put("slow",            "I think this has to do with your hardware. Upgrading your processor\n"            + "should solve all performance problems. Have you got a problem with\n"            + "our software?");    responseMap.put("performance",            "Performance was quite adequate in all our tests. Are you running\n"            + "any other processes in the background?");    responseMap.put("bug",            "Well, you know, all software has some bugs. But our software engineers\n"            + "are working very hard to fix them. Can you describe the problem a bit\n"            + "further?");    responseMap.put("buggy",            "Well, you know, all software has some bugs. But our software engineers\n"            + "are working very hard to fix them. Can you describe the problem a bit\n"            + "further?");    responseMap.put("windows",            "This is a known bug to do with the Windows operating system. Please\n"            + "report it to Microsoft. There is nothing we can do about this.");    responseMap.put("macintosh",            "This is a known bug to do with the Mac operating system. Please\n"            + "report it to Apple. There is nothing we can do about this.");    responseMap.put("expensive",            "The cost of our product is quite competitive. Have you looked around\n"            + "and really compared our features?");    responseMap.put("installation",            "The installation is really quite straight forward. We have tons of\n"            + "wizards that do all the work for you. Have you read the installation\n"            + "instructions?");    responseMap.put("memory",            "If you read the system requirements carefully, you will see that the\n"            + "specified memory requirements are 1.5 giga byte. You really should\n"            + "upgrade your memory. Anything else you want to know?");    responseMap.put("linux",            "We take Linux support very seriously. But there are some problems.\n"            + "Most have to do with incompatible glibc versions. Can you be a bit\n"            + "more precise?");    responseMap.put("bluej",            "Ahhh, BlueJ, yes. We tried to buy out those guys long ago, but\n"            + "they simply won't sell... Stubborn people they are. Nothing we can\n"            + "do about it, I'm afraid.");}private void fillDefaultResponses() {    defaultResponses.add("That sounds odd. Could you describe that problem in more detail?");    defaultResponses.add("No other customer has ever complained about this before. \n"            + "What is your system configuration?");    defaultResponses.add("That sounds interesting. Tell me more...");    defaultResponses.add("I need a bit more information on that.");    defaultResponses.add("Have you checked that you do not have a dll conflict?");    defaultResponses.add("That is explained in the manual. Have you read the manual?");    defaultResponses.add("Your description is a bit wishy-washy. Have you got an expert\n"            + "there with you who could describe this more precisely?");    defaultResponses.add("That's not a bug, it's a feature!");    defaultResponses.add("Could you elaborate on that?");}/** * Randomly select and return one of the default responses. * @return A random default response */private String pickDefaultResponse() {// Pick a random number for the index in the default response list.// The number will be between 0 (inclusive) and the size of the list (exclusive).    int index = randomGenerator.nextInt(defaultResponses.size());    return defaultResponses.get(index);}

Minor Irk:
You are using the wrong Collection type in generateResponse. You shouldn't ever been looking through a HashSet like that. The idea of a HashSet is you can find something in a single operation O(1) time. Change it to a Collection and everything is fine though. Plus, it is then possible to pass in things like ArrayLists



Given your restrictions, I would fill a map that maps a word from one form to the form stored in the responseMap.

So for example, you could do:

normalizer.put("crashy", "crash");normalizer.put("freeze", "crash");

That when, when you recive a word from your collection of words, you see if you can convert it into a standard from using the above map.

public String generateResponse(Collection words) {    for (String word : words ) {        String standardWord = normalizer.get(word);        if ( standardWord != null ){            world = standardWord;        }        String response = responseMap.get(word);        if (response != null) {            return response;        }    }    return pickDefaultResponse();}

Thanks! Will try it out when I get the chance.

Unfortunately, it doesn't seem to work. I post all the changes I've done to the original code in red and every code that isn't relevant isn't posted.
I've tried freeze and crashes but it just responds with a default response (not posted).
Edit: And before I forget, everything I posted is BlueJ's own code, but I'll keep in mind what you said about HashSet and colletions.


* Construct a Responder
*/
public Responder()
{
responseMap = new HashMap();
defaultResponses = new ArrayList();
fillResponseMap();
fillDefaultResponses();
randomGenerator = new Random();
Synonyms = new HashMap();
fillSynonyms();

}


public String generateResponse(HashSet words)
{
for (String word : words) {
String standardWord = Synonyms.get(word);
if( standardWord != null ){
word = standardWord;
}
String response = responseMap.get(word);
if(response != null) {
return response;
}
}
// If we get here, none of the words from the input line was recognized.
// In this case we pick one of our default responses (what we say when
// we cannot think of anything else to say...)
return pickDefaultResponse();
}


/**
* Enter all the known keywords and their associated responses
* into our response map.
*/
private void fillResponseMap()
{
responseMap.put("crash",
"Well, it never crashes on our system. It must have something\n" +
"to do with your system. Tell me more about your configuration.");
responseMap.put("slow",
"I think this has to do with your hardware. Upgrading your processor\n" +
"should solve all performance problems. Have you got a problem with\n" +
"our software?");
responseMap.put("performance",
"Performance was quite adequate in all our tests. Are you running\n" +
"any other processes in the background?");
responseMap.put("bug",
"Well, you know, all software has some bugs. But our software engineers\n" +
"are working very hard to fix them. Can you describe the problem a bit\n" +
"further?");
responseMap.put("buggy",
"Well, you know, all software has some bugs. But our software engineers\n" +
"are working very hard to fix them. Can you describe the problem a bit\n" +
"further?");
responseMap.put("windows",
"This is a known bug to do with the Windows operating system. Please\n" +
"report it to Microsoft. There is nothing we can do about this.");
responseMap.put("macintosh",
"This is a known bug to do with the Mac operating system. Please\n" +
"report it to Apple. There is nothing we can do about this.");
responseMap.put("expensive",
"The cost of our product is quite competitive. Have you looked around\n" +
"and really compared our features?");
responseMap.put("installation",
"The installation is really quite straight forward. We have tons of\n" +
"wizards that do all the work for you. Have you read the installation\n" +
"instructions?");
responseMap.put("memory",
"If you read the system requirements carefully, you will see that the\n" +
"specified memory requirements are 1.5 giga byte. You really should\n" +
"upgrade your memory. Anything else you want to know?");
responseMap.put("linux",
"We take Linux support very seriously. But there are some problems.\n" +
"Most have to do with incompatible glibc versions. Can you be a bit\n" +
"more precise?");
responseMap.put("bluej",
"Ahhh, BlueJ, yes. We tried to buy out those guys long ago, but\n" +
"they simply won't sell... Stubborn people they are. Nothing we can\n" +
"do about it, I'm afraid.");
}


private void fillSynonyms()
{
Synonyms.put("crashes", "crash");
Synonyms.put("freeze", "crash");
}
}

It seems to work fine though.

http://ideone.com/0ue8Y

Sorry, the reason I posted it didn't work was because I had another synonym I tested first and that was a 2 word one( messes up, but I wrote it less polite). Stupid of me!

Thanks a lot for the help, this helps me along a lot.