--- /dev/null
+package org.apache.lucene.analysis.tokenattributes;
+
+/**
+ * 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.
+ */
+
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.util.Attribute;
+
+/**
+ * This attribute can be used to mark a token as a keyword. Keyword aware
+ * {@link TokenStream}s can decide to modify a token based on the return value
+ * of {@link #isKeyword()} if the token is modified. Stemming filters for
+ * instance can use this attribute to conditionally skip a term if
+ * {@link #isKeyword()} returns <code>true</code>.
+ */
+public interface KeywordAttribute extends Attribute {
+
+ /**
+ * Returns <code>true</code> iff the current token is a keyword, otherwise
+ * <code>false</code>/
+ *
+ * @return <code>true</code> iff the current token is a keyword, otherwise
+ * <code>false</code>/
+ */
+ public boolean isKeyword();
+
+ /**
+ * Marks the current token as keyword iff set to <code>true</code>.
+ *
+ * @param isKeyword
+ * <code>true</code> iff the current token is a keyword, otherwise
+ * <code>false</code>.
+ */
+ public void setKeyword(boolean isKeyword);
+}