201504.mbox/raw/%3c20150426101833.B291DAC1436@hades.apache.org%3e

+    /*
+     * Licensed to the Apache Software Foundation (ASF) under one or more
+     * contributor license agreements.  See the NOTICE file distributed with
+     * this work for additional information regarding copyright ownership.
+     * The ASF licenses this file to You 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.
+     */
+    package org.apache.commons.text.similarity;
+
+    import java.util.ArrayList;
+    import java.util.List;
+    import java.util.regex.Matcher;
+    import java.util.regex.Pattern;
+
+    /**
+     * A simple word tokenizer that utilizes regex to find words. It applies a regex
+     * {@code}(\w)+{@code} over the input text to extract words from a given character
+     * sequence.
+     */
+    class RegexTokenizer implements Tokenizer<CharSequence> {
+
+        /**
+         * {@inheritDoc}
+         *
+         * @throws IllegalArgumentException if the input text is blank
+         */
+        @Override
+        public CharSequence[] tokenize(CharSequence text) {
+            if (text == null || text.toString().trim().equals("")) {
+                throw new IllegalArgumentException("Invalid text");
+            }
+            Pattern pattern = Pattern.compile("(\\w)+");
+            Matcher matcher = pattern.matcher(text.toString());
+            List<String> tokens = new ArrayList<String>();
+            while (matcher.find()) {
+                tokens.add(matcher.group(0));
+            }
+            return tokens.toArray(new String[0]);
+        }
+
+    }
+