INT-4292: More Diagnostics

https://jira.spring.io/browse/INT-4292

Add class-level log adjuster.

spring-integration-test/src/main/java/org/springframework/integration/test/rule/Log4jClassLevelAdjuster.java

@@ -0,0 +1,103 @@
+/*
+ * Copyright 2017 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.test.rule;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.LinkedHashSet;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.log4j.Level;
+import org.apache.log4j.LogManager;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+/**
+ * Similar to {@code Log4jLevelAdjuster} that can be applied as a @ClassRule but you
+ * will not get a log message indicating breaks between tests.
+ *
+ * @author Dave Syer
+ * @author Gary Russell
+ *
+ */
+public class Log4jClassLevelAdjuster extends TestWatcher {
+
+	private static final Log logger = LogFactory.getLog(Log4jClassLevelAdjuster.class);
+
+	private final Class<?>[] classes;
+
+	private final Level level;
+
+	private final String[] categories;
+
+	public Log4jClassLevelAdjuster(Level level, Class<?>... classes) {
+		this.level = level;
+		this.classes = classes;
+		this.categories = new String[0];
+	}
+
+	public Log4jClassLevelAdjuster(Level level, String... categories) {
+		this.level = level;
+		this.classes = new Class<?>[0];
+		Set<String> cats = new LinkedHashSet<String>(Arrays.asList(categories));
+		cats.add(getClass().getPackage().getName());
+		this.categories = new ArrayList<String>(cats).toArray(new String[cats.size()]);
+	}
+
+	@Override
+	public Statement apply(final Statement base, final Description description) {
+		return new Statement() {
+			@Override
+			public void evaluate() throws Throwable {
+				Map<Class<?>, Level> oldLevels = new HashMap<Class<?>, Level>();
+				for (Class<?> cls : classes) {
+					oldLevels.put(cls, LogManager.getLogger(cls).getEffectiveLevel());
+					LogManager.getLogger(cls).setLevel(level);
+				}
+				Map<String, Level> oldCatLevels = new HashMap<String, Level>();
+				for (String category : categories) {
+					oldCatLevels.put(category, LogManager.getLogger(category).getEffectiveLevel());
+					LogManager.getLogger(category).setLevel(level);
+				}
+				logger.debug("++++++++++++++++++++++++++++ "
+						+ "Overridden log level setting for: " + Arrays.asList(classes) + " and "
+						+ Arrays.asList(categories) + " for test " + description.getDisplayName());
+				try {
+					base.evaluate();
+				}
+				finally {
+					logger.debug("++++++++++++++++++++++++++++ "
+							+ "Restoring log level setting for: " + Arrays.asList(classes) + " and "
+							+ Arrays.asList(categories) + " for test " + description.getDisplayName());
+					// raw Class type used to avoid http://bugs.sun.com/view_bug.do?bug_id=6682380
+					for (@SuppressWarnings("rawtypes") Class cls : classes) {
+						LogManager.getLogger(cls).setLevel(oldLevels.get(cls));
+					}
+					for (String category : categories) {
+						LogManager.getLogger(category).setLevel(oldCatLevels.get(category));
+					}
+				}
+			}
+		};
+	}
+
+}