public int[] List(String keyword) {
int counter = 0; // this counts the number of occurrences of the given keyword
int[] arr; // keeps page numbers of the given keyword
ListNode result;
int page; // holds the current page number
result =
ht2.chainedHashSearch(
ht2,
keyword); // check whether there's at least a single page with the given keyword,if the
// node prsent we get the first one,there can be more !!!
if (result != null) {
page = result.getPage();
counter = 1; // found one occurence of the keyword
// now let's find all the other occurrences of the same keyword
while (result.getNext() != null) { // iterate through the whole list
result = result.getNext();
if (result.getKeyword().equals(keyword) && result.getPage() != page) {
counter++;
page = result.getPage();
}
}
// now we know how many pages contain the given key word
// let's create an array to hold all the page numbers
arr = new int[counter];
// let's iterate through the same linked list again to feed the array with page numbers
counter = 0; // reset to zero again
result = ht2.chainedHashSearch(ht2, keyword);
arr[0] = page = result.getPage();
counter = 1;
while (result.getNext() != null) {
result = result.getNext();
if (result.getKeyword().equals(keyword) && result.getPage() != page) {
arr[counter] = result.getPage();
counter++;
}
}
this.sort(arr);
return arr;
} else {
return null;
}
}
public void readInput(Scanner s) {
String line;
Calendar cal = new GregorianCalendar(); // a calendar object to show current time and date
BufferedWriter bw;
line = s.nextLine();
while (s.hasNext()) {
if (line.trim().equals("Keyword List Start")) {
line = s.nextLine().trim();
while (!(line.equals("Keyword List End"))) {
char arr[] = line.toCharArray();
// now let's count the length of the keyword
int len = 0;
while (arr[len] != '\t') {
len++;
if (len == arr.length - 1) {
try {
bw = new BufferedWriter(new FileWriter("output.txt"));
bw.write("invalid input format given and program terminated on " + cal.getTime());
bw.flush();
bw.close();
break;
} catch (IOException ex) {
}
System.exit(0); // terminate the program if input is invalid
}
}
String kw = line.substring(0, len); // extract the keyword
/**
* now we check whether the keyword has spaces at both ends if white spaces present, that
* is an invalid input and the program will be terminated.
*/
if (kw.equals(kw.trim()) && arr[len] == '\t') {
kw = kw.toLowerCase(); // the reason for this action is described below
int pageNum =
Integer.parseInt(
line.trim().substring(len + 1, arr.length)); // extract the pagenumber
/**
* now observe the two lines above. we know that each line contains a keyword and a tab
* letter and an integer(page number) if we perform trim() method on each line we get
* the string which has no spaces at two ends then we insert the trimmed string into a
* char[] arr, say size n page number is obviously the last element of the
* array,arr[n-1] the tab letter is the arr[n-2] th element then the sequence from
* arr[0] to arr[n-2] belongs to the keyword It is said that keywords are not case
* sensitive.(e.g. "CSE" = "cSe") hence all strings are stored after converting to the
* lower case
*/
ListNode node1 = new ListNode(pageNum, kw);
ListNode node2 = new ListNode(pageNum, kw);
ht2.chainedHashInsert(ht2, node2);
ht1.chainedHashInsert(ht1, node1);
line = s.nextLine().trim();
} else {
try {
bw = new BufferedWriter(new FileWriter("output.txt"));
bw.write("invalid input format given and program terminated on " + cal.getTime());
bw.flush();
bw.close();
break;
} catch (IOException ex) {
}
System.exit(0); // terminate the program if input is invalid
}
}
/*
* input is read and finished storing keywords
now we sacn queries
*
*/
line = s.nextLine();
String queryWord; // holds the command words, "First", "List" and "Keywords"
String qkeyword; // holds the keyword, queried by the commands
if (line.trim().equals("Queries Start")) {
while (!(line.trim().equals("Queries End"))) {
/**
* this block of code will read through the queries list and perform the three
* operations First, List and Keywords
*/
line = s.nextLine();
String trimmed =
line
.trim(); // trim() to remove boundary white spaces and ignore input errors at
// ends
char[] array = trimmed.toCharArray();
if (trimmed.substring(0, 4).equals("List")
&& trimmed.charAt(4) == ' '
&& trimmed.charAt(5) != (' ')) {
queryWord =
"List"; // this string is not used. but I use it so that it can be used for future
// development purposes
qkeyword = trimmed.substring(5, array.length);
int[] pageArray = this.List(qkeyword.toLowerCase());
this.showSorted(pageArray);
} else if (trimmed.substring(0, 5).equals("First")
&& trimmed.charAt(5) == ' '
&& trimmed.charAt(6) != (' ')) {
queryWord = "First";
qkeyword = trimmed.substring(6, array.length);
this.First(qkeyword.toLowerCase());
} else if (trimmed.substring(0, 8).equals("Keywords")
&& trimmed.charAt(8) == ' '
&& trimmed.charAt(9) != (' ')) {
queryWord = "Keywords";
int pageNumber =
Integer.parseInt(trimmed.substring(9, array.length)); // extract the pagenumber
this.Keywords(pageNumber);
} else if (trimmed.equals("Queries End")) {
System.exit(0);
} else { // if none of the above cases occur then it is an invalid input
try {
bw = new BufferedWriter(new FileWriter("output.txt"));
bw.write("invalid input format given and program terminated on " + cal.getTime());
bw.flush();
bw.close();
break;
} catch (IOException ex) {
}
System.exit(0);
}
}
} else {
try {
bw = new BufferedWriter(new FileWriter("output.txt"));
bw.write("invalid input format at " + cal.getTime());
bw.flush();
bw.close();
} catch (IOException ex) {
}
System.exit(0);
}
} else {
try {
bw = new BufferedWriter(new FileWriter("output.txt"));
bw.write("invalid input format at " + cal.getTime());
bw.flush();
bw.close();
} catch (IOException ex) {
}
}
}
}
