INT-3164: Fix Scripting Refresh

Previously, there was no logic to check, if a JSR223 script
was modified should be refreshed from the external resource.

* Fix `RefreshableResourceScriptSource` to take care of refreshing
on call `isModified()`
* Add `scriptSource.isModified()` before getting script text
* Introduce `ScriptSourceFactoryBean` to avoid I/O operations, when
there is need to refresh script resource - `refreshDelay < 0`

JIRA: https://jira.springsource.org/browse/INT-3164

INT-3164: change the refresh mutation logic

Remove factory bean - no longer needed.

spring-integration-scripting/src/test/java/org/springframework/integration/scripting/config/jsr223/Int3164Jsr223RefreshTests-context.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<beans:beans xmlns="http://www.springframework.org/schema/integration"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xmlns:beans="http://www.springframework.org/schema/beans"
+	xmlns:script="http://www.springframework.org/schema/integration/scripting"
+	xsi:schemaLocation="http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration.xsd
+		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
+		http://www.springframework.org/schema/integration/scripting http://www.springframework.org/schema/integration/scripting/spring-integration-scripting.xsd">
+
+	<transformer input-channel="referencedScriptInput" output-channel="outputChannel">
+		<script:script refresh-check-delay="0"
+				location="file:#{T(System).getProperty('java.io.tmpdir')}/Int3164Jsr223RefreshTests/int3164.groovy"/>
+	</transformer>
+
+	<channel id="outputChannel">
+		<queue/>
+	</channel>
+
+</beans:beans>

spring-integration-scripting/src/test/java/org/springframework/integration/scripting/config/jsr223/Int3164Jsr223RefreshTests.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2013 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.scripting.config.jsr223;
+
+import static org.junit.Assert.assertEquals;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.integration.MessageChannel;
+import org.springframework.integration.core.PollableChannel;
+import org.springframework.integration.message.GenericMessage;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.util.FileCopyUtils;
+
+/**
+ * @author Artem Bilan
+ * @since 3.0
+ */
+@ContextConfiguration
+@RunWith(SpringJUnit4ClassRunner.class)
+public class Int3164Jsr223RefreshTests {
+
+	private static File workDir;
+
+	private static File scriptFile;
+
+	@Autowired
+	private MessageChannel referencedScriptInput;
+
+	@Autowired
+	private PollableChannel outputChannel;
+
+	@BeforeClass
+	public static void start() throws IOException {
+		String basePath = System.getProperty("java.io.tmpdir") + File.separator + "Int3164Jsr223RefreshTests";
+		workDir = new File(basePath);
+		shutdown();
+		workDir.mkdir();
+		workDir.deleteOnExit();
+		scriptFile = new File(workDir, "int3164.groovy");
+		scriptFile.createNewFile();
+		FileCopyUtils.copy("1".getBytes(), scriptFile);
+	}
+
+	@AfterClass
+	public static void shutdown() {
+		if (workDir != null && workDir.exists()) {
+			for (File file : workDir.listFiles()) {
+				file.delete();
+			}
+			workDir.delete();
+		}
+	}
+
+	@Test
+	public void testRefreshingScript() throws Exception {
+		this.referencedScriptInput.send(new GenericMessage<Object>("test"));
+		assertEquals(1, this.outputChannel.receive(100).getPayload());
+
+		FileCopyUtils.copy("2".getBytes(), scriptFile);
+		scriptFile.setLastModified(System.currentTimeMillis() + 10000); // force refresh
+
+		this.referencedScriptInput.send(new GenericMessage<Object>("test"));
+		assertEquals(2, this.outputChannel.receive(100).getPayload());
+	}
+
+}