LogService: extract logging methods to a superinterface

We are going to add support for multiple Logger objects in the same
SciJava context. The LogService instance will itself be the default
Logger, but there will be others as well.

Author: ctrueden

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

@@ -45,7 +45,7 @@
  * 
  * @author Curtis Rueden
  */
-public interface LogService extends SciJavaService {
+public interface LogService extends SciJavaService, Logger {
 
 	/** System property to set for overriding the default logging level. */
 	String LOG_LEVEL_PROPERTY = "scijava.log.level";
@@ -71,48 +71,6 @@ public interface LogService extends SciJavaService {
 	@Deprecated
 	int TRACE = LogLevel.TRACE;
 
-	void debug(Object msg);
-
-	void debug(Throwable t);
-
-	void debug(Object msg, Throwable t);
-
-	void error(Object msg);
-
-	void error(Throwable t);
-
-	void error(Object msg, Throwable t);
-
-	void info(Object msg);
-
-	void info(Throwable t);
-
-	void info(Object msg, Throwable t);
-
-	void trace(Object msg);
-
-	void trace(Throwable t);
-
-	void trace(Object msg, Throwable t);
-
-	void warn(Object msg);
-
-	void warn(Throwable t);
-
-	void warn(Object msg, Throwable t);
-
-	boolean isDebug();
-
-	boolean isError();
-
-	boolean isInfo();
-
-	boolean isTrace();
-
-	boolean isWarn();
-
-	int getLevel();
-
 	void setLevel(int level);
 
 	void setLevel(String classOrPackageName, int level);

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

@@ -0,0 +1,88 @@
+/*
+ * #%L
+ * SciJava Common shared library for SciJava software.
+ * %%
+ * Copyright (C) 2009 - 2017 Board of Regents of the University of
+ * Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck
+ * Institute of Molecular Cell Biology and Genetics.
+ * %%
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ * #L%
+ */
+
+package org.scijava.log;
+
+/**
+ * Interface for objects which can produce log messages.
+ * <p>
+ * It provides methods for logging messages, exception stack traces and
+ * combinations of the two.
+ * </p>
+ * 
+ * @author Curtis Rueden
+ * @see LogLevel
+ * @see LogService
+ */
+public interface Logger {
+
+	void debug(Object msg);
+
+	void debug(Throwable t);
+
+	void debug(Object msg, Throwable t);
+
+	void error(Object msg);
+
+	void error(Throwable t);
+
+	void error(Object msg, Throwable t);
+
+	void info(Object msg);
+
+	void info(Throwable t);
+
+	void info(Object msg, Throwable t);
+
+	void trace(Object msg);
+
+	void trace(Throwable t);
+
+	void trace(Object msg, Throwable t);
+
+	void warn(Object msg);
+
+	void warn(Throwable t);
+
+	void warn(Object msg, Throwable t);
+
+	boolean isDebug();
+
+	boolean isError();
+
+	boolean isInfo();
+
+	boolean isTrace();
+
+	boolean isWarn();
+
+	int getLevel();
+}