Added FileNameGenerator strategy and DefaultFileNameGenerator implementation.

org.springframework.integration.file/src/main/java/org/springframework/integration/file/DefaultFileNameGenerator.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2002-2008 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.integration.file;
+
+import org.springframework.integration.message.Message;
+import org.springframework.util.StringUtils;
+
+/**
+ * Default implementation of the filename generator strategy. It first checks
+ * for the "filename" Message header, then falls back to the Message ID.
+ * 
+ * @author Mark Fisher
+ */
+public class DefaultFileNameGenerator implements FileNameGenerator {
+
+	public String generateFileName(Message<?> message) {
+		String filenameProperty = message.getHeaders().get(FILENAME_PROPERTY_KEY, String.class);
+		return StringUtils.hasText(filenameProperty) ?
+				filenameProperty : message.getHeaders().getId() + ".msg";
+	}
+
+}

org.springframework.integration.file/src/main/java/org/springframework/integration/file/FileNameGenerator.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2002-2008 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.integration.file;
+
+import org.springframework.integration.message.Message;
+
+/**
+ * Strategy interface for generating a file name from a message.
+ * 
+ * @author Mark Fisher
+ */
+public interface FileNameGenerator {
+
+	String FILENAME_PROPERTY_KEY = "filename";
+
+
+	String generateFileName(Message<?> message);
+
+}