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Get parameters of nested functions

I am trying to implement a parser in Java to extract the arguments of some functions.
When I have a function like:
max(1, 2, 3)
I just simply can use a Regular Expresion to extract the args.
But all my functions are not like that. If I have some nested function, eg:
max(sum(1, max(1,2,sum(2,5)), 3, 5, mult(3,3))
I would like to obtain:
sum(1, max(1,2,sum(2,5))
3
5
mult(3,3)
I tried using a Regular Expression, but I asume the language is not regular. Another approach was splliting by ',', but did not work as well.
Is there any method for extracting the arguments of a function? I do not really know how this type of problem can be solved since there is no a pattern to use for extracting the arguments.
Any help or insight would be really appreciated. Thanks!!

Parsing a source code into an some abstract model is quite complex topic, depending on the language complexity.
But first step is usually tokenization, where you read one character at a time and detect full tokens (like variable names, function names, operators, literals etc).
Since you presented only very limited scope for the problem , you have very small set of tokens:
name of a function
( and ) to indicate method call
, to separate arguments
numbers
Reading one symbol at the time, you should be able to very easily detect when one token ends and the next one begins. Also your tokens are very distinct (i.e. you don't have to differentiate function name from variable name), you can very easily categorize them.
Once you have a token, you know the grammar (you have only function calls), you can easily build a syntax tree (where at the root you have top level function call with its arguments being children nodes).
From that structure you can easily fetch whichever parts you wish.
If you are more interested in how it works in the javac compiler, you can always check out its source code (it's open source after all):
https://github.com/openjdk/jdk/blob/master/src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java
https://github.com/openjdk/jdk/blob/master/src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavaTokenizer.java
However, that may be quite a long read.

Finally found a method that works:
public List<String> parseArgs(String l){
int startIdx = l.indexOf("(") + 1;
int endIdx = l.lastIndexOf(")") - 1;
int count = 0;
int argIdx = startIdx;
List<String> args = new ArrayList<>();
for (int i = startIdx; i < endIdx; i++) {
if (l.charAt(i) == '(')
count -= 1;
else if (l.charAt(i) == ')'){
count += 1;
}
else if (l.charAt(i) == ',' && count == 0){
args.add(l.substring(argIdx, i).trim());
argIdx = i + 1;
}
}
args.add(l.substring(argIdx, endIdx + 1).trim());
return args;
}
String l = "max(sum(1, max(1,2,sum(2,5))), 3, 5, mult(3,3))";
parseArgs(l).forEach(System.out::println);
//Prints
sum(1, max(1,2,sum(2,5)))
3
5
mult(3,3)

Auto completion function Java

I am working on a Displaykeyboard for disabled peaople and i am thinking about to adding a auto word completion function.
I found a example from oracle that works as i need it. Its the Another Example: TextAreaDemo. The problem is i dont really understand the search algorithm and the problem is when i add some word to the arraylist the search algorithm stops working properly.
String prefix = content.substring(w + 1).toLowerCase();
int n = Collections.binarySearch(words, prefix);
if (n < 0 && -n <= words.size()) {
String match = words.get(-n - 1);
if (match.startsWith(prefix)) {
// A completion is found
String completion = match.substring(pos - w);
// We cannot modify Document from within notification,
// so we submit a task that does the change later
SwingUtilities.invokeLater(
new CompletionTask(completion, pos + 1));
}
} else {
// Nothing found
mode = Mode.INSERT;
}
Is there a way to modify the example so it will work with any words?

Make sure you're not just adding the word to the end of the list and then using binarySearch(). It's documentation says the following
The list must be sorted into ascending order according to the natural
ordering of its elements (as by the sort(List) method) prior to making
this call.
Read more about it here: https://docs.oracle.com/javase/7/docs/api/java/util/Collections.html#binarySearch(java.util.List,%20T)

Java Class chartobyteconverter Type deprecated

I am working on DNA proteins alignment project "readseq" . Its "flybase " package contains java code having " charToByteConverter" class which does not compile and gives the " type deprecated " message. (http://iubio.bio.indiana.edu/soft/molbio/readseq/java/).
Here readseq source can be foundI need to add some more functionality into this application, don't know how to fix it to proceed towards my goal. I am a kind of new bie in java. Plz help if possible. Readseq is with its gui is easily available on net.
It just converts an array of given characters to bytes. Here is some info about it: (docjar.com/docs/api/sun/io/CharToByteConverter.html) . I don't know what to do about this being deprecated.
It is an abstract class used as under:
protected byte[] getBytes(CharToByteConverter ctb) {
ctb.reset();
int estLength = ctb.getMaxBytesPerChar() * count;
byte[] result = new byte[estLength];
int length;
try {
length = ctb.convert(value, offset, offset + count,
result, 0, estLength);
length += ctb.flush(result, ctb.nextByteIndex(), estLength);
} catch (CharConversionException e) {
length = ctb.nextByteIndex();
}
if (length < estLength) {
// A short format was used: Trim the byte array.
byte[] trimResult = new byte[length];
System.arraycopy(result, 0, trimResult, 0, length);
return trimResult;
}
else {
return result;
}
}

The javadoc comment says it all:
Deprecated! Replaced - by java.nio.charset
Look for a replacement class/method in the java.nio.charset package.
Note that using classes in the JDK that are not part of the officially documented API is a bad idea in the first place.

This is a perfect case for Adapt Parameter, from Michael Feathers book Working Effectively With Legacy Code.
Shameless self-plug: Here's a short prezi I did on it. It has a step-by-step breakdown of what you need to do.
Essentially, you're going to have to modify the code you have and apply the Adapter Pattern to the parameter. You'll want to define your own interface (let's call it ByteSource), make getBytes() take your interface instead (getBytes(ByteSource ctb)), then make the Adapter that internally has a CharToByteConverter for testing. To fix the broken library, you should make one that has a java.nio.charset instead.

Suggestion on equalsIgnoreCase in Java to C implementation

All,
In a bid to improve my C skills, I decided to start implementing various Java libraries/library functions to C code. This would ensure that everyone knows the functionality of my implementation at least. Here is the link to the C source code that simulates the equalsIgnoreCase() of String class in Java : C source code. I have tested the code and it looks fine as per my testing skills are concerned. My aim was to use as much basic operations and datatypes as possible. Though, it would be great if the gurus here can:
1 > Give me any suggestion to improve the code quality
2 > Enlighten me with any missing coding standard/practices
3 > Locate bugs in my logic.

100 lines of code is not too long to post here.
You calculate the string length twice. In C, the procedure to calculate the string length starts at the beginning of the string and runs along all of it (not necessarily in steps of 1 byte) until it finds the terminating null byte. If your strings are 2Mbyte long, you "walk" along 4Mbyte unnecessarily.
in <ctype.h> there are the two functions tolower() and toupper() declared. You can use one of them (tolower) instead of extractFirstCharacterASCIIVal(). The advantage of using the library function is that it is not locked in to ASCII and may even work with foreign characters when you go 'international'.
You use awkward (very long) names for your variables (and functions too). eg: ch1 and ch2 do very well for characters in file 1 and file 2 respectively :-)
return 1; at the end of main usually means something went wrong with the program. return 0; is idiomatic for successful termination.
Edit: for comparison with tcrosley version
#include <ctype.h>
int cmpnocase(const char *s1, const char *s2) {
while (*s1 && *s2) {
if (tolower((unsigned char)*s1) != tolower((unsigned char)*s2)) break;
s1++;
s2++;
}
return (*s1 != *s2);
}

With C++, you could replace performComparison(char* string1, char * string2) with stricmp.
However stricmp is not part of the standard C library. Here is a version adapted to your example. Note you don't need the extractFirstCharacterASCIIVal function, use tolower instead. Also note there is no need to explicitly calculate the string length ahead of time, as strings in C are terminated by the NULL character '\0'.
int performComparison(char* string1, char * string2)
{
char c1, c2;
int v;
do {
c1 = *string1++;
c2 = *string2++;
v = (UINT) tolower(c1) - (UINT) tolower(c2);
} while ((v == 0) && (c1 != '\0') && (c2 != '\0') );
return v != 0;
}
If you do want to use your own extractFirstCharacterASCIIVal function instead of the tolower macro, to make the code more transparent then you should code it like so:
if ((str >= 'a') && (str <= 'z'))
{
returnVal = str - ('a' - 'A');
}
else
{
returnVal = str;
}
to make it more obvious what you are doing. Also you should include a comment that this assumes the characters a..z and A..Z are contiguous. (They are in ASCII, but not always in other encodings.)

Javabat substring counting

public boolean catDog(String str)
{
int count = 0;
for (int i = 0; i < str.length(); i++)
{
String sub = str.substring(i, i+1);
if (sub.equals("cat") && sub.equals("dog"))
count++;
}
return count == 0;
}
There's my code for catDog, have been working on it for a while and just cannot find out what's wrong. Help would be much appreciated!*/
EDIT- I want to Return true if the string "cat" and "dog" appear the same number of times in the given string.

One problem is that this will never be true:
if (sub.equals("cat") && sub.equals("dog"))
&& means and. || means or.
However, another problem is that your code looks like your are flailing around randomly trying to get it to work. Everyone does this to some extent in their first programming class, but it's a bad habit. Try to come up with a clear mental picture of how to solve the problem before you write any code, then write the code, then verify that the code actually does what you think it should do and that your initial solution was correct.
EDIT: What I said goes double now that you've clarified what your function is supposed to do. Your approach to solving the problem is not correct, so you need to rethink how to solve the problem, not futz with the implementation.

Here's a critique since I don't believe in giving code for homework. But you have at least tried which is better than most of the clowns posting homework here.
you need two variables, one for storing cat occurrences, one for dog, or a way of telling the difference.
your substring isn't getting enough characters.
a string can never be both cat and dog, you need to check them independently and update the right count.
your return statement should return true if catcount is equal to dogcount, although your version would work if you stored the differences between cats and dogs.
Other than those, I'd be using string searches rather than checking every position but that may be your next assignment. The method you've chosen is perfectly adequate for CS101-type homework.
It should be reasonably easy to get yours working if you address the points I gave above. One thing you may want to try is inserting debugging statements at important places in your code such as:
System.out.println(
"i = " + Integer.toString (i) +
", sub = ["+sub+"]" +
", count = " + Integer.toString(count));
immediately before the closing brace of the for loop. This is invaluable in figuring out what your code is doing wrong.
Here's my ROT13 version if you run into too much trouble and want something to compare it to, but please don't use it without getting yours working first. That doesn't help you in the long run. And, it's almost certain that your educators are tracking StackOverflow to detect plagiarism anyway, so it wouldn't even help you in the short term.
Not that I really care, the more dumb coders in the employment pool, the better it is for me :-)
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vag qvssrerapr = 0;
sbe (vag v = 0; v < fge.yratgu() - 2; v++) {
Fgevat fho = fge.fhofgevat(v, v+3);
vs (fho.rdhnyf("png")) {
qvssrerapr++;
} ryfr {
vs (fho.rdhnyf("qbt")) {
qvssrerapr--;
}
}
}
erghea qvssrerapr == 0;
}

Another thing to note here is that substring in Java's built-in String class is exclusive on the upper bound.
That is, for String str = "abcdefg", str.substring( 0, 2 ) retrieves "ab" rather than "abc." To match 3 characters, you need to get the substring from i to i+3.

My code for do this:
public boolean catDog(String str) {
if ((new StringTokenizer(str, "cat")).countTokens() ==
(new StringTokenizer(str, "dog")).countTokens()) {
return true;
}
return false;
}
Hope this will help you
EDIT: Sorry this code will not work since you can have 2 tokens side by side in your string. Best if you use countMatches from StringUtils Apache commons library.

String sub = str.substring(i, i+1);
The above line is only getting a 2-character substring so instead of getting "cat" you'll get "ca" and it will never match. Fix this by changing 'i+1' to 'i+2'.
Edit: Now that you've clarified your question in the comments: You should have two counter variables, one to count the 'dog's and one to count the 'cat's. Then at the end return true if count_cats == count_dogs.