Add support for the --main argument

Using --main-class also works, for partial backwards compatibility.

This feature leans on the new MainService to do most of the work.

Author: ctrueden

src/main/java/org/scijava/main/console/MainArgument.java

@@ -0,0 +1,99 @@
+/*
+ * #%L
+ * SciJava Common shared library for SciJava software.
+ * %%
+ * Copyright (C) 2009 - 2015 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.main.console;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.scijava.console.AbstractConsoleArgument;
+import org.scijava.console.ConsoleArgument;
+import org.scijava.log.LogService;
+import org.scijava.main.MainService;
+import org.scijava.plugin.Parameter;
+import org.scijava.plugin.Plugin;
+
+/**
+ * Handles the {@code --main} command line argument, which launches an
+ * alternative main class.
+ * 
+ * @author Curtis Rueden
+ */
+@Plugin(type = ConsoleArgument.class)
+public class MainArgument extends AbstractConsoleArgument {
+
+	@Parameter(required = false)
+	private MainService mainService;
+
+	@Parameter(required = false)
+	private LogService log;
+
+	// -- ConsoleArgument methods --
+
+	@Override
+	public void handle(final LinkedList<String> args) {
+		if (!supports(args)) return;
+
+		args.removeFirst(); // --main / --main-class
+		final String className = args.removeFirst();
+
+		final List<String> argList = new ArrayList<String>();
+		while (!args.isEmpty() && !isMainFlag(args) && !isSeparator(args)) {
+			argList.add(args.removeFirst());
+		}
+		if (isSeparator(args)) args.removeFirst(); // remove the -- separator
+		final String[] mainArgs = argList.toArray(new String[argList.size()]);
+
+		mainService.addMain(className, mainArgs);
+	}
+
+	// -- Typed methods --
+
+	@Override
+	public boolean supports(final LinkedList<String> args) {
+		return mainService != null && isMainFlag(args);
+	}
+
+	// -- Helper methods --
+
+	private boolean isMainFlag(final LinkedList<String> args) {
+		if (args == null || args.isEmpty()) return false;
+		final String arg = args.getFirst();
+		return arg.equals("--main") || arg.equals("--main-class");
+	}
+
+	private boolean isSeparator(final LinkedList<String> args) {
+		if (args == null || args.isEmpty()) return false;
+		return args.getFirst().equals("--");
+	}
+
+}