Allow setting log levels for specified LogSources

Author: maarzt

src/main/java/org/scijava/log/AbstractLogService.java

@@ -84,6 +84,11 @@ public void setLevel(final String classOrPackageName, final int level) {
 		classAndPackageLevels.put(classOrPackageName, level);
 	}
 
+	@Override
+	public void setLevelForLogger(final String source, final int level) {
+		rootLogger.getSource().subSource(source).setLogLevel(level);
+	}
+
 	// -- Logger methods --
 
 	@Override

src/main/java/org/scijava/log/DefaultLogger.java

@@ -77,7 +77,9 @@ public void alwaysLog(final int level, final Object msg, final Throwable t) {
 	}
 
 	public Logger subLogger(final String name, final int level) {
-		return new DefaultLogger(this, source.subSource(name), level);
+		LogSource source = getSource().subSource(name);
+		int actualLevel = source.hasLogLevel() ? source.logLevel() : level;
+		return new DefaultLogger(this, source, actualLevel);
 	}
 
 	// -- Listenable methods --

src/main/java/org/scijava/log/LogService.java

@@ -50,6 +50,30 @@ public interface LogService extends SciJavaService, Logger {
 	/** System property to set for overriding the default logging level. */
 	String LOG_LEVEL_PROPERTY = "scijava.log.level";
 
+	String LOG_LEVEL_BY_SOURCE_PROPERTY = "scijava.log.level.source";
+
+	/** Changes the log level of the root logger */
+	void setLevel(int level);
+
+	/**
+	 * For messages that are logged directly to the LogService. The log level can
+	 * be set depending on the class that makes the log.
+	 * 
+	 * @param classOrPackageName If this is the name of a class. Messages logged
+	 *          directly by this class are logged, if the message's level is less
+	 *          or equal to the given level. If this is a package, the same holds
+	 *          for all classes in this package.
+	 * @param level Given level.
+	 */
+	void setLevel(String classOrPackageName, int level);
+
+	/**
+	 * Setting the log level for loggers depending on their {@link LogSource}.
+	 * This will only effect loggers that are created after is method has been
+	 * called.
+	 */
+	void setLevelForLogger(String source, int level);
+
 	// -- Deprecated --
 
 	/** @deprecated Use {@link LogLevel#NONE}. */
@@ -70,9 +94,4 @@ public interface LogService extends SciJavaService, Logger {
 	/** @deprecated Use {@link LogLevel#TRACE}. */
 	@Deprecated
 	int TRACE = LogLevel.TRACE;
-
-	void setLevel(int level);
-
-	void setLevel(String classOrPackageName, int level);
-
 }

src/main/java/org/scijava/log/LogSource.java

@@ -45,6 +45,8 @@
  */
 public class LogSource {
 
+	public static final String SEPARATOR = ":";
+
 	private final LogSource parent;
 
 	private final List<String> path;
@@ -54,6 +56,8 @@ public class LogSource {
 
 	private String formatted = null;
 
+	private Integer logLevel;
+
 	private LogSource(LogSource parent, String name) {
 		this.parent = parent;
 		List<String> parentPath = parent.path();
@@ -73,6 +77,19 @@ public static LogSource newRoot() {
 		return new LogSource();
 	}
 
+	/**
+	 * Returns a log source with the given path.
+	 *
+	 * @param subPath Relative path to the source, divided by
+	 *          {@link LogSource#SEPARATOR}.
+	 */
+	public LogSource subSource(final String subPath) {
+		LogSource result = this;
+		for (final String name : subPath.split(SEPARATOR))
+			result = result.child(name);
+		return result;
+	}
+
 	/** Returns the list of strings which is represented by this LogSource. */
 	public List<String> path() {
 		return path;
@@ -84,22 +101,10 @@ public String name() {
 		return path.get(path.size() - 1);
 	}
 
-	/**
-	 * Returns the LogSource which represents the path of this LogSource extended
-	 * by name.
-	 */
-	public LogSource subSource(String name) {
-		LogSource child = children.get(name);
-		if (child != null) return child;
-		child = new LogSource(this, name);
-		children.putIfAbsent(name, child);
-		return children.get(name);
-	}
-
 	@Override
 	public String toString() {
 		if (formatted != null) return formatted;
-		StringJoiner joiner = new StringJoiner(":");
+		StringJoiner joiner = new StringJoiner(SEPARATOR);
 		path.forEach(s -> joiner.add(s));
 		formatted = joiner.toString();
 		return formatted;
@@ -113,4 +118,28 @@ public boolean isRoot() {
 	public LogSource parent() {
 		return parent;
 	}
+
+	public void setLogLevel(int logLevel) {
+		this.logLevel = logLevel;
+	}
+
+	public boolean hasLogLevel() {
+		return logLevel != null;
+	}
+
+	public int logLevel() {
+		if (!hasLogLevel()) throw new IllegalStateException();
+		return logLevel;
+	}
+
+	// -- Helper methods --
+
+	private LogSource child(final String name) {
+		if (name.isEmpty()) return this;
+		LogSource child = children.get(name);
+		if (child != null) return child;
+		child = new LogSource(this, name);
+		children.putIfAbsent(name, child);
+		return children.get(name);
+	}
 }

src/test/java/org/scijava/log/LogServiceTest.java

@@ -156,6 +156,15 @@ public void testClassLogLevelViaProperties() {
 		assertEquals(LogLevel.ERROR, level);
 	}
 
+	@Test
+	public void testSubLoggerLogLevel() {
+		final TestableLogService log = new TestableLogService();
+		log.setLevel(LogLevel.ERROR);
+		log.setLevelForLogger("foo:bar", LogLevel.TRACE);
+		Logger sub = log.subLogger("foo").subLogger("bar");
+		assertEquals(LogLevel.TRACE, sub.getLevel());
+	}
+
 	@Test
 	public void testPackageLogLevel() {
 		final LogService log = new TestableLogService();

src/test/java/org/scijava/log/LogSourceTest.java

@@ -31,11 +31,14 @@
 
 package org.scijava.log;
 
-import org.junit.Test;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
 
 import java.util.Collections;
 
-import static org.junit.Assert.*;
+import org.junit.Test;
 
 /**
  * Tests {@link LogSource}
@@ -64,6 +67,14 @@ public void testChildIsUnique() {
 		assertSame(a, b);
 	}
 
+	@Test
+	public void testLogSourceParse() {
+		LogSource foo = LogSource.newRoot().subSource("foo");
+		LogSource result = foo.subSource("Hello:World");
+		LogSource expected = foo.subSource("Hello").subSource("World");
+		assertEquals(expected, result);
+	}
+
 	@Test
 	public void testToString() {
 		LogSource source = LogSource.newRoot().subSource("Hello").subSource("World");
@@ -90,4 +101,18 @@ public void testParent() {
 		LogSource source = root.subSource("sub");
 		assertSame(root, source.parent());
 	}
+
+	@Test
+	public void testUnsetLogLevel() {
+		LogSource source = LogSource.newRoot();
+		assertFalse(source.hasLogLevel());
+	}
+
+	@Test
+	public void testSetLogLevel() {
+		LogSource source = LogSource.newRoot();
+		source.setLogLevel(LogLevel.INFO);
+		assertTrue(source.hasLogLevel());
+		assertEquals(LogLevel.INFO, source.logLevel());
+	}
 }