move the word list loader from analysis.de to analysis, as it is not specific to German at all

git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@150436 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/lucene/analysis/WordlistLoader.java

@@ -0,0 +1,109 @@
+package org.apache.lucene.analysis;
+
+/**
+ * Copyright 2004 The Apache Software Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.LineNumberReader;
+import java.util.HashSet;
+import java.util.Hashtable;
+import java.util.Iterator;
+
+/**
+ * Loader for text files that represent a list of stopwords.
+ *
+ * @author Gerhard Schwarz
+ * @version $Id$
+ */
+public class WordlistLoader {
+
+  /**
+   * Loads a text file and adds every line as an entry to a HashSet (omitting
+   * leading and trailing whitespace). Every line of the file should contain only 
+   * one word. The words need to be in lowercase if you make use of an
+   * Analyzer which uses LowerCaseFilter (like GermanAnalyzer).
+   * 
+   * @param wordfile File containing the wordlist
+   * @return A HashSet with the file's words
+   */
+  public static HashSet getWordSet(File wordfile) throws IOException {
+    HashSet result = new HashSet();
+    FileReader freader = null;
+    LineNumberReader lnr = null;
+    try {
+      freader = new FileReader(wordfile);
+      lnr = new LineNumberReader(freader);
+      String word = null;
+      while ((word = lnr.readLine()) != null) {
+        result.add(word.trim());
+      }
+    }
+    finally {
+      if (lnr != null)
+        lnr.close();
+      if (freader != null)
+        freader.close();
+    }
+    return result;
+  }
+
+  /**
+   * @param path      Path to the wordlist
+   * @param wordfile  Name of the wordlist
+   * 
+   * @deprecated Use {@link #getWordSet(File)} getWordSet(File)} instead
+   */
+  public static Hashtable getWordtable(String path, String wordfile) throws IOException {
+    return getWordtable(new File(path, wordfile));
+  }
+
+  /**
+   * @param wordfile  Complete path to the wordlist
+   * 
+   * @deprecated Use {@link #getWordSet(File)} getWordSet(File)} instead
+   */
+  public static Hashtable getWordtable(String wordfile) throws IOException {
+    return getWordtable(new File(wordfile));
+  }
+
+  /**
+   * @param wordfile  File object that points to the wordlist
+   *
+   * @deprecated Use {@link #getWordSet(File)} getWordSet(File)} instead
+   */
+  public static Hashtable getWordtable(File wordfile) throws IOException {
+    HashSet wordSet = (HashSet)getWordSet(wordfile);
+    Hashtable result = makeWordTable(wordSet);
+    return result;
+  }
+
+  /**
+   * Builds a wordlist table, using words as both keys and values
+   * for backward compatibility.
+   *
+   * @param wordSet   stopword set
+   */
+  private static Hashtable makeWordTable(HashSet wordSet) {
+    Hashtable table = new Hashtable();
+    for (Iterator iter = wordSet.iterator(); iter.hasNext();) {
+      String word = (String)iter.next();
+      table.put(word, word);
+    }
+    return table;
+  }
+}