introduced extended WritableResource interface

Author: jhoeller

org.springframework.core/src/main/java/org/springframework/core/io/FileSystemResource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2008 the original author or authors.
+ * Copyright 2002-2011 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,8 +18,10 @@
 
 import java.io.File;
 import java.io.FileInputStream;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.net.URI;
 import java.net.URL;
 
@@ -29,12 +31,13 @@
 /**
  * {@link Resource} implementation for <code>java.io.File</code> handles.
  * Obviously supports resolution as File, and also as URL.
+ * Implements the extended {@link WritableResource} interface.
  *
  * @author Juergen Hoeller
  * @since 28.12.2003
  * @see java.io.File
  */
-public class FileSystemResource extends AbstractResource {
+public class FileSystemResource extends AbstractResource implements WritableResource {
 
 	private final File file;
 
@@ -166,6 +169,27 @@ public String getDescription() {
 	}
 
 
+	// implementation of WritableResource
+
+	/**
+	 * This implementation checks whether the underlying file is marked as writable
+	 * (and corresponds to an actual file with content, not to a directory).
+	 * @see java.io.File#canWrite()
+	 * @see java.io.File#isDirectory()
+	 */
+	public boolean isWritable() {
+		return (this.file.canWrite() && !this.file.isDirectory());
+	}
+
+	/**
+	 * This implementation opens a FileOutputStream for the underlying file.
+	 * @see java.io.FileOutputStream
+	 */
+	public OutputStream getOutputStream() throws IOException {
+		return new FileOutputStream(this.file);
+	}
+
+
 	/**
 	 * This implementation compares the underlying File references.
 	 */

org.springframework.core/src/main/java/org/springframework/core/io/Resource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2011 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -35,12 +35,13 @@
  * @see #getURL()
  * @see #getURI()
  * @see #getFile()
+ * @see WritableResource
+ * @see ContextResource
  * @see FileSystemResource
  * @see ClassPathResource
  * @see UrlResource
  * @see ByteArrayResource
  * @see InputStreamResource
- * @see org.springframework.web.context.support.ServletContextResource
  */
 public interface Resource extends InputStreamSource {
 
@@ -59,6 +60,7 @@ public interface Resource extends InputStreamSource {
 	 * note that actual content reading may still fail when attempted.
 	 * However, a value of <code>false</code> is a definitive indication
 	 * that the resource content cannot be read.
+	 * @see #getInputStream()
 	 */
 	boolean isReadable();
 

org.springframework.core/src/main/java/org/springframework/core/io/WritableResource.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2002-2011 the original author or authors.
+ *
+ * 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.
+ */
+
+package org.springframework.core.io;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * Extended interface for a resource that supports writing to it.
+ * Provides an {@link #getOutputStream() OutputStream accessor}.
+ *
+ * @author Juergen Hoeller
+ * @since 3.1
+ * @see java.io.OutputStream
+ */
+public interface WritableResource extends Resource {
+
+	/**
+	 * Return whether the contents of this resource can be modified,
+	 * e.g. via {@link #getOutputStream()} or {@link #getFile()}.
+	 * <p>Will be <code>true</code> for typical resource descriptors;
+	 * note that actual content writing may still fail when attempted.
+	 * However, a value of <code>false</code> is a definitive indication
+	 * that the resource content cannot be modified.
+	 * @see #getOutputStream()
+	 * @see #isReadable()
+	 */
+	boolean isWritable();
+
+	/**
+	 * Return an {@link OutputStream} for the underlying resource,
+	 * allowing to (over-)write its content.
+	 * @throws IOException if the stream could not be opened
+	 * @see #getInputStream()
+	 */
+	OutputStream getOutputStream() throws IOException;
+
+}