Author: oheger
Date: Sun Sep 22 17:46:34 2013
New Revision: 1525394
URL: http://svn.apache.org/r1525394
Log:
Added FileLocationStrategy interface.
This interface will be used for making the process of resolving files
customizable.
Added:
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/io/FileLocationStrategy.java
Added:
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/io/FileLocationStrategy.java
URL:
http://svn.apache.org/viewvc/commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/io/FileLocationStrategy.java?rev=1525394&view=auto
==============================================================================
---
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/io/FileLocationStrategy.java
(added)
+++
commons/proper/configuration/trunk/src/main/java/org/apache/commons/configuration/io/FileLocationStrategy.java
Sun Sep 22 17:46:34 2013
@@ -0,0 +1,69 @@
+/*
+ * 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.configuration.io;
+
+import java.net.URL;
+
+/**
+ * <p>
+ * An interface allowing applications to customize the process of locating a
+ * file.
+ * </p>
+ * <p>
+ * {@link FileHandler} uses {@link FileLocator} objects for referencing files.
+ * These objects are not guaranteed to identify a file in a unique way. For
+ * instance, if only a file name is defined, this could mean a relative file
+ * name in the current directory, the name of a resource to be loaded from the
+ * class path, or something else. Before the file described by a
+ * {@code FileLocator} can be actually accessed, an unambiguous URL pointing to
+ * this file has to be obtained. This is the job of a
+ * {@code FileLocationStrategy}.
+ * </p>
+ * <p>
+ * This interface defines a method for locating a file provided as a
+ * {@code FileLocator} object. If location is successful, a URL is returned. A
+ * concrete implementation can perform arbitrary actions to search for the file
+ * in question at various places. There will also be an implementation allowing
+ * the combination of multiple {@code FileLocationStrategy} implementations; so
+ * a file can be searched using multiple strategies until one of them is
+ * successful.
+ * </p>
+ *
+ * @version $Id: $
+ * @since 2.0
+ */
+public interface FileLocationStrategy
+{
+ /**
+ * Tries to locate the specified file. The method also expects the
+ * {@code FileSystem} to be used. Note that the {@code FileLocator} object
+ * may also contain a {@code FileSystem}, but this is optional. The passed
+ * in {@code FileSystem} should be used, and callers must not pass a
+ * <b>null</b> reference for this argument. A concrete implementation has
to
+ * evaluate the properties stored in the {@code FileLocator} object and try
+ * to match them to an existing file. If this can be done, a corresponding
+ * URL is returned. Otherwise, result is <b>null</b>. Implementations
should
+ * not throw an exception (unless parameters are <b>null</b>) as there
might
+ * be alternative strategies which can find the file in question.
+ *
+ * @param fileSystem the {@code FileSystem} to be used for this operation
+ * @param locator the object describing the file to be located
+ * @return a URL pointing to the referenced file if location was
successful;
+ * <b>null</b> if the file could not be resolved
+ */
+ URL locate(FileSystem fileSystem, FileLocator locator);
+}
