New FileExist option for File component: TryRename

camel-core/src/main/java/org/apache/camel/component/file/GenericFileExist.java

@@ -23,5 +23,5 @@
  */
 public enum GenericFileExist {
 
-    Override, Append, Fail, Ignore, Move
+    Override, Append, Fail, Ignore, Move, TryRename
 }

camel-core/src/main/java/org/apache/camel/component/file/GenericFileProducer.java

@@ -123,25 +123,32 @@ protected void processExchange(Exchange exchange, String target) throws Exceptio
                 tempTarget = createTempFileName(exchange, target);
 
                 log.trace("Writing using tempNameFile: {}", tempTarget);
-
-                // cater for file exists option on the real target as
-                // the file operations code will work on the temp file
-
-                // if an existing file already exists what should we do?
-                targetExists = operations.existsFile(target);
-                if (targetExists) {
-                    if (endpoint.getFileExist() == GenericFileExist.Ignore) {
-                        // ignore but indicate that the file was written
-                        log.trace("An existing file already exists: {}. Ignore and do not override it.", target);
-                        return;
-                    } else if (endpoint.getFileExist() == GenericFileExist.Fail) {
-                        throw new GenericFileOperationFailedException("File already exist: " + target + ". Cannot write new file.");
-                    } else if (endpoint.isEagerDeleteTargetFile() && endpoint.getFileExist() == GenericFileExist.Override) {
-                        // we override the target so we do this by deleting it so the temp file can be renamed later
-                        // with success as the existing target file have been deleted
-                        log.trace("Eagerly deleting existing file: {}", target);
-                        if (!operations.deleteFile(target)) {
-                            throw new GenericFileOperationFailedException("Cannot delete file: " + target);
+
+                //if we should eager delete target file before deploying temporary file
+                if (endpoint.getFileExist() != GenericFileExist.TryRename && endpoint.isEagerDeleteTargetFile()) {
+
+                    // cater for file exists option on the real target as
+                    // the file operations code will work on the temp file
+
+                    // if an existing file already exists what should we do?
+                    targetExists = operations.existsFile(target);
+                    if (targetExists) {
+
+                        log.trace("EagerDeleteTargetFile, target exists");
+
+                        if (endpoint.getFileExist() == GenericFileExist.Ignore) {
+                            // ignore but indicate that the file was written
+                            log.trace("An existing file already exists: {}. Ignore and do not override it.", target);
+                            return;
+                        } else if (endpoint.getFileExist() == GenericFileExist.Fail) {
+                            throw new GenericFileOperationFailedException("File already exist: " + target + ". Cannot write new file.");
+                        } else if (endpoint.isEagerDeleteTargetFile() && endpoint.getFileExist() == GenericFileExist.Override) {
+                            // we override the target so we do this by deleting it so the temp file can be renamed later
+                            // with success as the existing target file have been deleted
+                            log.trace("Eagerly deleting existing file: {}", target);
+                            if (!operations.deleteFile(target)) {
+                                throw new GenericFileOperationFailedException("Cannot delete file: " + target);
+                            }
                         }
                     }
                 }
@@ -161,15 +168,29 @@ protected void processExchange(Exchange exchange, String target) throws Exceptio
             // if we did write to a temporary name then rename it to the real
             // name after we have written the file
             if (tempTarget != null) {
-
-                // if we should not eager delete the target file then do it now just before renaming
-                if (!endpoint.isEagerDeleteTargetFile() && targetExists
-                        && endpoint.getFileExist() == GenericFileExist.Override) {
-                    // we override the target so we do this by deleting it so the temp file can be renamed later
-                    // with success as the existing target file have been deleted
-                    log.trace("Deleting existing file: {}", target);
-                    if (!operations.deleteFile(target)) {
-                        throw new GenericFileOperationFailedException("Cannot delete file: " + target);
+                // if we did not eager delete the target file
+                if (endpoint.getFileExist() != GenericFileExist.TryRename && !endpoint.isEagerDeleteTargetFile()) {
+
+                    // if an existing file already exists what should we do?
+                    targetExists = operations.existsFile(target);
+                    if (targetExists) {
+
+                        log.trace("Not using EagerDeleteTargetFile, target exists");
+
+                        if (endpoint.getFileExist() == GenericFileExist.Ignore) {
+                            // ignore but indicate that the file was written
+                            log.trace("An existing file already exists: {}. Ignore and do not override it.", target);
+                            return;
+                        } else if (endpoint.getFileExist() == GenericFileExist.Fail) {
+                            throw new GenericFileOperationFailedException("File already exist: " + target + ". Cannot write new file.");
+                        } else if (endpoint.getFileExist() == GenericFileExist.Override) {
+                            // we override the target so we do this by deleting it so the temp file can be renamed later
+                            // with success as the existing target file have been deleted
+                            log.trace("Deleting existing file: {}", target);
+                            if (!operations.deleteFile(target)) {
+                                throw new GenericFileOperationFailedException("Cannot delete file: " + target);
+                            }
+                        }
                     }
                 }
 

camel-core/src/test/java/org/apache/camel/component/file/FileProducerFileExistTryRenameTest.java

@@ -0,0 +1,65 @@
+/**
+ * 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.camel.component.file;
+
+import java.util.Locale;
+
+import junit.framework.TestResult;
+import org.apache.camel.ContextTestSupport;
+import org.apache.camel.Exchange;
+import org.apache.camel.TestSupport;
+import org.apache.camel.builder.RouteBuilder;
+import org.apache.camel.component.mock.MockEndpoint;
+
+/**
+ * @version 
+ */
+public class FileProducerFileExistTryRenameTest extends ContextTestSupport {
+
+   @Override
+    protected void setUp() throws Exception {
+        deleteDirectory("target/file");
+        super.setUp();
+        template.sendBodyAndHeader("file://target/file", "Hello World", Exchange.FILE_NAME, "hello.txt");
+    }
+
+
+    public void testIgnore() throws Exception {
+
+        // Does not work on Windows
+        if(TestSupport.isPlatform("windows"))
+            return;
+
+        MockEndpoint mock = getMockEndpoint("mock:result");
+        mock.expectedBodiesReceived("Bye World");
+        mock.expectedFileExists("target/file/hello.txt", "Bye World");
+
+        template.sendBodyAndHeader("file://target/file?fileExist=TryRename&tempPrefix=tmp", "Bye World", Exchange.FILE_NAME, "hello.txt");
+
+        assertMockEndpointsSatisfied();
+    }
+
+    @Override
+    protected RouteBuilder createRouteBuilder() throws Exception {
+        return new RouteBuilder() {
+            @Override
+            public void configure() throws Exception {
+                from("file://target/file?noop=true&delay=1000").convertBodyTo(String.class).to("mock:result");
+            }
+        };
+    }
+}