Iterator for directories containing text files.

src/cc/mallet/pipe/iterator/TextFileIterator.java

@@ -0,0 +1,112 @@
+package cc.mallet.pipe.iterator;
+
+import cc.mallet.types.Instance;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FilenameFilter;
+import java.util.Iterator;
+import java.util.Scanner;
+/**
+*  An iterator that iterates through a directory and returns
+ *  one instance per file. <p>
+ */
+
+public class TextFileIterator implements Iterator<Instance>
+{
+  File[] fileList;
+  int currentFile;
+
+
+
+  /**
+   * Defaults constructor
+   * @param path  the path of the file (s)
+   * @param filter  filename ending
+   */
+  public TextFileIterator(String path, String filter){
+    try {
+      fileIterator(path, filter);
+    } catch (FileNotFoundException e) {
+      e.printStackTrace();
+    }
+  }
+
+
+  /**
+   * A private file iterator that creates an array containing all files at the given directory path.
+   * @param path  The directory path.
+   * @throws FileNotFoundException  if the path is not a directory.
+   */
+  private void fileIterator(String path, String langCode) throws FileNotFoundException {
+    if (langCode.equals(null))
+      langCode = "";
+    if (fileList == null) {
+      File dir = new File(path);
+      if (dir.isDirectory()) {
+        final String finalLangCode = langCode;
+        fileList = dir.listFiles(new FilenameFilter() {
+          @Override
+          public boolean accept(File dir, String name) {
+            return name.endsWith(finalLangCode +".txt");
+          }
+        });
+      }
+      else {
+        throw new IllegalStateException("The given path is not a directory.");
+      }
+    }
+  }
+
+  /**
+   * A private file reader that reads through the current file.
+   * @return  The content of the file read.
+   * @throws FileNotFoundException  if the file is not found.
+   */
+  private String readFile() throws FileNotFoundException {
+    Scanner scanner = new Scanner(fileList[currentFile], "UTF-8");
+    String text = "";
+    while (scanner.hasNextLine()) {
+      String line = scanner.nextLine().trim();
+      if(line.length()> 2)
+        text += line;
+    }
+    scanner.close();
+    return text;
+  }
+
+  /**
+   * Next instance
+   * @return  The next instance (next file)
+   */
+  public Instance next(){
+    String data = null;
+    try {
+      data = readFile();
+    } catch (FileNotFoundException e) {
+      e.printStackTrace();
+    }
+    String name = fileList[currentFile].getName();
+
+    int underScorePos = 0;
+    if(name.contains("_"))
+      underScorePos = name.indexOf("_");
+    String target = name.substring(underScorePos+1, name.indexOf("."));
+    String uri = name.substring(0, underScorePos);
+    currentFile++;
+    if (data == null){
+      throw new IllegalStateException("The iterated file contained no data.");
+    }
+    return new Instance(data, target, uri, null);
+  }
+
+  /**
+   * @return true if there are more files in the iterator.
+   */
+  public boolean hasNext ()	{ return fileList.length > currentFile;	}
+
+  public void remove () {
+    throw new IllegalStateException ("This Iterator<Instance> does not support remove().");
+  }
+
+}