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+package project3;
+//
+// WORDS. An iterator that reads lower case words from a text file.
+//
+// James Moen
+// 19 Apr 17
+//
+
+import java.io.FileReader; // Read Unicode chars from a file.
+import java.io.IOException; // In case there's IO trouble.
+
+// WORDS. Iterator. Read words, represented as STRINGs, from a text file. Each
+// word is the longest possible contiguous series of alphabetic ASCII CHARs.
+
+class Words {
+ private int ch; // Last CHAR from READER, as an INT.
+ private FileReader reader; // Read CHARs from here.
+ private StringBuilder word; // Last word read from READER.
+
+ // Constructor. Initialize an instance of WORDS, so it reads words from a file
+ // whose pathname is PATH. Throw an exception if we can't open PATH.
+
+ public Words(String path) {
+ try {
+ reader = new FileReader(path);
+ ch = reader.read();
+ } catch (IOException ignore) {
+ throw new IllegalArgumentException("Cannot open '" + path + "'.");
+ }
+ }
+
+ // HAS NEXT. Try to read a WORD from READER, converting it to lower case as we
+ // go. Test if we were successful.
+
+ public boolean hasNext() {
+ word = new StringBuilder();
+ while (ch > 0 && !isAlphabetic((char) ch)) {
+ read();
+ }
+ while (ch > 0 && isAlphabetic((char) ch)) {
+ word.append(toLower((char) ch));
+ read();
+ }
+ return word.length() > 0;
+ }
+
+ // IS ALPHABETIC. Test if CH is an ASCII letter.
+
+ private boolean isAlphabetic(char ch) {
+ return 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z';
+ }
+
+ // NEXT. If HAS NEXT is true, then return a WORD read from READER as a STRING.
+ // Otherwise, return an undefined STRING.
+
+ public String next() {
+ return word.toString();
+ }
+
+ // READ. Read the next CHAR from READER. Set CH to the CHAR, represented as an
+ // INT. If there are no more CHARs to be read from READER, then set CH to -1.
+
+ private void read() {
+ try {
+ ch = reader.read();
+ } catch (IOException ignore) {
+ ch = -1;
+ }
+ }
+
+ // TO LOWER. Return the lower case ASCII letter which corresponds to the ASCII
+ // letter CH.
+
+ private char toLower(char ch) {
+ if ('a' <= ch && ch <= 'z') {
+ return ch;
+ } else {
+ return (char) (ch - 'A' + 'a');
+ }
+ }
+ // MAIN. For testing. Open a text file whose pathname is the 0th argument from
+ // the command line. Read words from the file, and print them one per line.
+
+ public static void main(String[] args) {
+ Words words = new Words(args[0]);
+ while (words.hasNext()) {
+ System.out.println("'" + words.next() + "'");
+ }
+ }
+}