Add ScriptHeader implementation

Created a ScriptHeader plugin for the JRuby language.

Currently this will generate a header for performing a relative import
of the imaegej.rb script, if present.

Author: hinerm

src/main/java/org/scijava/plugins/scripting/jruby/JRubyScriptHeader.java

@@ -0,0 +1,83 @@
+/*
+ * #%L
+ * JSR-223-compliant JRuby scripting language plugin.
+ * %%
+ * Copyright (C) 2008 - 2014 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.plugins.scripting.jruby;
+
+import java.io.File;
+
+import org.scijava.app.AppService;
+import org.scijava.plugin.Parameter;
+import org.scijava.plugin.Plugin;
+import org.scijava.script.AbstractScriptHeader;
+import org.scijava.script.ScriptHeader;
+import org.scijava.script.ScriptLanguage;
+
+/**
+ * Provides a default script header when editing {@link JRubyScriptLanguage}
+ * scripts. This automatically imports the {@code imagej.rb} utility script.
+ *
+ * @author Mark Hiner
+ */
+@Plugin(type = ScriptHeader.class)
+public class JRubyScriptHeader extends AbstractScriptHeader {
+
+	@Parameter
+	private AppService appService;
+
+	// -- ScriptHeader Methods --
+
+	@Override
+	public String getHeader() {
+
+		String header = null;
+
+		final String imagejPath =
+			File.separator + "plugins" + File.separator + "JRuby" + File.separator +
+				"imagej.rb";
+
+		if (new File(appService.getApp().getBaseDirectory() + imagejPath).exists())
+		{
+			header =
+				"# @AppService appService\n" +
+					"require_relative \"#{$appService.getApp.getBaseDirectory}" +
+					imagejPath + "\"";
+		}
+
+		return header;
+	}
+
+	// -- AbstractScriptHeader methods --
+
+	@Override
+	protected Class<? extends ScriptLanguage> handledType() {
+		return JRubyScriptLanguage.class;
+	}
+}