BATCH-1454: added Poller interface

spring-batch-infrastructure/src/test/java/org/springframework/batch/poller/DirectPollerTests.java

@@ -0,0 +1,106 @@
+/*
+ * Copyright 2006-2010 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.batch.poller;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+
+import org.junit.Test;
+
+/**
+ * @author Dave Syer
+ * 
+ */
+public class DirectPollerTests {
+
+	private Set<String> repository = new HashSet<String>();
+
+	@Test
+	public void testSimpleSingleThreaded() throws Exception {
+
+		Callable<String> callback = new Callable<String>() {
+
+			public String call() throws Exception {
+				Set<String> executions = new HashSet<String>(repository);
+				if (executions.isEmpty()) {
+					return null;
+				}
+				return executions.iterator().next();
+			}
+
+		};
+
+		sleepAndCreateStringInBackground(500L);
+
+		Future<String> task = new DirectPoller<String>(100L).poll(callback);
+
+		String value = task.get(1000L, TimeUnit.MILLISECONDS);
+		assertEquals("foo", value);
+
+	}
+
+	@Test
+	public void testWithError() throws Exception {
+
+		Callable<String> callback = new Callable<String>() {
+
+			public String call() throws Exception {
+				Set<String> executions = new HashSet<String>(repository);
+				if (executions.isEmpty()) {
+					return null;
+				}
+				throw new RuntimeException("Expected");
+			}
+
+		};
+
+		Poller<String> poller = new DirectPoller<String>(100L);
+
+		sleepAndCreateStringInBackground(500L);
+
+		try {
+			String value = poller.poll(callback).get(1000L, TimeUnit.MILLISECONDS);
+			assertEquals(null, value);
+			fail("Expected ExecutionException");
+		}
+		catch (ExecutionException e) {
+			assertEquals("Expected", e.getCause().getMessage());
+		}
+
+	}
+
+	private void sleepAndCreateStringInBackground(final long duration) {
+		new Thread(new Runnable() {
+			public void run() {
+				try {
+					Thread.sleep(duration);
+					repository.add("foo");
+				}
+				catch (Exception e) {
+					throw new IllegalStateException("Unexpected");
+				}
+			}
+		}).start();
+	}
+
+}