3 files changed, 228 insertions, 0 deletions

diff --git a/src/com/ensemble/wordcount/LengthComparator.java b/src/com/ensemble/wordcount/LengthComparator.java
new file mode 100644
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+++ b/src/com/ensemble/wordcount/LengthComparator.java
@@ -0,0 +1,17 @@
+package com.ensemble.wordcount;
+
+import java.util.Comparator;
+
+	/**
+	 * A Comparator class for comparing the lengths of strings
+	 * This is used for sorting the list of words by length
+	 * 
+	 * @author Joe Robinson
+	 */
+	public class LengthComparator implements Comparator<String> {
+
+		@Override
+		public int compare(String string1, String string2) {
+			return string2.length() - string1.length();
+		}
+	}
\ No newline at end of file
diff --git a/src/com/ensemble/wordcount/WordCount.java b/src/com/ensemble/wordcount/WordCount.java
new file mode 100644
index 0000000..c6a63d0
--- /dev/null
+++ b/src/com/ensemble/wordcount/WordCount.java
@@ -0,0 +1,103 @@
+package com.ensemble.wordcount;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * This program may be used to count the number of occurences of words in a given file.
+ * Words are not counted if they are contained within a larger word (eg "is" and "this")
+ * 
+ * @author Joe Robinson
+ *
+ */
+public class WordCount {
+	
+	public static void main(String args[]) {
+
+		//Need to use a concurrent hashmap as we will be modifying it as we loop through
+		Map<String,Integer> wordCounts = new ConcurrentHashMap<String,Integer>();
+		List<String> words = new ArrayList<String>();
+		WordUtil wordUtil = new WordUtil();
+		String filename = "";
+		
+		while (filename.equals("")) {	
+	
+			//If an argument has been entered, use it as the filename, if not prompt for one
+			if (args.length > 0 && args[0] != null) {
+				filename = args[0];
+			} else {
+				filename = readFilename();
+			}
+			
+			try {
+				words = wordUtil.readWordsFromFile(filename);
+	
+			} catch (IOException e) {
+				System.out.println("Could not open file. Please try another.");
+				filename = "";
+				words = new ArrayList<String>();
+			}
+			
+			//Check that the file actually contains some words, if not then prompt for another
+			if (words.size() == 0) {
+				System.out.println("File does not contain any words. Please try another file.");
+				filename = "";
+				words = new ArrayList<String>();
+			}
+			
+		}
+		wordCounts = wordUtil.countWords(words);
+
+		List<String> sortedWords = wordUtil.sortWords(wordCounts);
+		
+		System.out.println();
+		
+		for (String word : sortedWords) {
+			
+			//Capitalise the first letter of the word for output
+			char firstChar = Character.toUpperCase(word.charAt(0));
+			String outputWord = firstChar + word.substring(1);
+			
+			System.out.println(outputWord + ": " + wordCounts.get(word));
+		}
+	}
+	
+	/**
+	 * Prompt the user for a filename to read until one is entered, and confirm that it exists
+	 * @return The filename, which is confirmed to exist
+	 */
+	private static String readFilename() {
+		
+		String filename = "";
+		boolean fileExists = false;
+		while (filename == null || filename.equals("") || !fileExists) {
+			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+			try {
+				System.out.println("Please enter a file name to read, or type \"q\" to quit");
+				filename = br.readLine();
+			} catch (IOException e) {
+				System.out.println("Could not read input");
+				System.exit(1);
+			}
+			
+			if (filename.equals("q")) {
+				System.exit(0);
+			}
+			
+			File file = new File(filename);
+			
+			if (file.exists()) {
+				fileExists = true;
+			} else {
+				System.out.println("File does not exist. Try again");
+			}
+		}
+		return filename;
+	}
+}
diff --git a/src/com/ensemble/wordcount/WordUtil.java b/src/com/ensemble/wordcount/WordUtil.java
new file mode 100644
index 0000000..0344f4c
--- /dev/null
+++ b/src/com/ensemble/wordcount/WordUtil.java
@@ -0,0 +1,108 @@
+package com.ensemble.wordcount;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * This class contains various utility functions for counting words
+ * @author Joe Robinson
+ *
+ */
+public class WordUtil {
+
+	/**
+	 * Reads all the words from a given file
+	 * 
+	 * @param filename	A String containing the filename or path to read from
+	 * @return			A List containing all words in the file
+	 */
+	public List<String> readWordsFromFile(String filename) throws IOException {
+		
+		FileReader fr = new FileReader(filename);
+		BufferedReader br = new BufferedReader(fr);
+		
+		String line = br.readLine();
+		String[] tmpWords;
+		List<String> words = new ArrayList<String>();
+		
+		while (line != null) {
+			
+			tmpWords = line.split(" ");
+			
+			//Remove all punctuation and convert all words to lower case for processing
+			for (String tmpWord : tmpWords) {
+				words.add(tmpWord.replaceAll("[^a-zA-Z]", "").toLowerCase());
+			}
+			
+			line = br.readLine();
+		}
+		
+		br.close();
+	
+		return words;
+	}
+	
+	/**
+	 * Counts the number of occurrences of a word in a given list of words
+	 * Words will not be counted if they are a substring of another word in the list
+	 * 
+	 * @param words	A list containing single word strings
+	 * @return		A map with the word as the key, and the number of occurrences as the value
+	 */
+	public Map<String,Integer> countWords(List<String> words) {
+		
+		Map<String,Integer> wordCounts = new ConcurrentHashMap<String,Integer>();
+		
+		for (String newWord : words) {
+			
+			//If the exact word is already a key in the map, increment it's count
+			if (wordCounts.containsKey(newWord)) {
+				wordCounts.put(newWord, wordCounts.get(newWord) + 1);
+			} else {
+				
+				boolean addWord = true;
+				
+				for (String countedWord : wordCounts.keySet()) {
+					
+					//If an existing word in the map contains this word, don't count it
+					if (countedWord.contains(newWord)) {
+						addWord = false;
+						break;
+					//If this word contains any of the existing words, remove them from the map
+					} else if (newWord.contains(countedWord)) {
+						wordCounts.remove(countedWord);
+					}
+				}
+				
+				//Add the word to the map as long as it wasn't found in an existing word
+				if (addWord) {
+					wordCounts.put(newWord, 1);
+				}
+			}
+		}
+		return wordCounts;
+	}
+	
+	/**
+	 * Extract a sorted list of the words in the map based on their length
+	 * @param wordCounts	A map containing strings as the key. Value is not used
+	 * 
+	 * @return				A list of the keys sorted into descending order of length
+	 */
+	public List<String> sortWords(Map<String, ?> wordCounts) {
+		
+		LengthComparator lengthCompare = new LengthComparator();
+		List<String> sortedWords = new ArrayList<String>(wordCounts.keySet());
+		
+		Collections.sort(sortedWords, lengthCompare);
+		
+		return sortedWords;
+	}
+
+}