pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / queryparser / src / java / org / apache / lucene / queryParser / ext / ParserExtension.java

diff --git a/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/ext/ParserExtension.java b/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/ext/ParserExtension.java
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+++ b/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/ext/ParserExtension.java
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+package org.apache.lucene.queryParser.ext;
+
+/**
+ * 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.queryParser.ParseException;
+import org.apache.lucene.queryParser.QueryParser;
+import org.apache.lucene.search.Query;
+
+/**
+ * This class represents an extension base class to the Lucene standard
+ * {@link QueryParser}. The {@link QueryParser} is generated by the JavaCC
+ * parser generator. Changing or adding functionality or syntax in the standard
+ * query parser requires changes to the JavaCC source file. To enable extending
+ * the standard query parser without changing the JavaCC sources and re-generate
+ * the parser the {@link ParserExtension} can be customized and plugged into an
+ * instance of {@link ExtendableQueryParser}, a direct subclass of
+ * {@link QueryParser}.
+ * 
+ * @see Extensions
+ * @see ExtendableQueryParser
+ */
+public abstract class ParserExtension {
+
+  /**
+   * Processes the given {@link ExtensionQuery} and returns a corresponding
+   * {@link Query} instance. Subclasses must either return a {@link Query}
+   * instance or raise a {@link ParseException}. This method must not return
+   * <code>null</code>.
+   * 
+   * @param query
+   *          the extension query
+   * @return a new query instance
+   * @throws ParseException
+   *           if the query can not be parsed.
+   */
+  public abstract Query parse(final ExtensionQuery query) throws ParseException;
+
+}