(HOA path) PathUtil: Some static helper methods for dealing with paths

prism/src/common/PathUtil.java

@@ -0,0 +1,99 @@
+//==============================================================================
+//	
+//	Copyright (c) 2016-
+//	Authors:
+//	* Joachim Klein <klein@tcs.inf.tu-dresden.de> (TU Dresden)
+//	
+//------------------------------------------------------------------------------
+//	
+//	This file is part of PRISM.
+//	
+//	PRISM is free software; you can redistribute it and/or modify
+//	it under the terms of the GNU General Public License as published by
+//	the Free Software Foundation; either version 2 of the License, or
+//	(at your option) any later version.
+//	
+//	PRISM is distributed in the hope that it will be useful,
+//	but WITHOUT ANY WARRANTY; without even the implied warranty of
+//	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//	GNU General Public License for more details.
+//	
+//	You should have received a copy of the GNU General Public License
+//	along with PRISM; if not, write to the Free Software Foundation,
+//	Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+//	
+//==============================================================================
+
+package common;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Path;
+
+import parser.ast.ModulesFile;
+import parser.ast.PropertiesFile;
+
+/**
+ * Static helpers for dealing with paths.
+ */
+public class PathUtil
+{
+	/**
+	 * Returns the absolute path for the directory containing
+	 * the argument file. Returns {@code null} on error, e.g.,
+	 * if the file does not exist.
+	 */
+	public static File getDirectoryFromFile(File file) {
+		return getDirectoryFromFile(file.toPath()).toFile();
+	}
+
+	/**
+	 * Returns the absolute path for the directory containing
+	 * the argument file. Returns {@code null} on error, e.g.,
+	 * if the file does not exist.
+	 */
+	public static Path getDirectoryFromFile(Path filePath) {
+		try {
+			return filePath.toRealPath().getParent();
+		} catch (IOException e) {
+			// E.g., file does not exist
+			return null;
+		}
+	}
+
+	/**
+	 * Returns the path for the directory that is used for loading
+	 * resources (e.g. a HOA automata file) in a property,
+	 * extracting locations from the ModulesFile and PropertiesFile.
+	 * <br>
+	 * The location of the properties file is preferred, then the location
+	 * of the modules file. If there is no location, {@code null} is returned
+	 * and should be treated as "current working directory".
+	 */
+	public static Path getDirectoryForRelativePropertyResource(ModulesFile mf, PropertiesFile pf)
+	{
+		if (pf != null && pf.getLocation() != null) {
+			return getDirectoryFromFile(pf.getLocation());
+		}
+
+		if (mf != null && mf.getLocation() != null) {
+			return getDirectoryFromFile(mf.getLocation());
+		}
+
+		return null;
+	}
+
+	
+	/**
+	 * Resolves path2 relative to path1 (which has to point to a directory).
+	 * If path2 is absolute, path1 is ignored.
+	 * If path1 is {@code null}, resolution happens relative
+	 * to the current working directory.
+	 */
+	public static Path resolvePath(Path path1, Path path2) {
+		if (path1 == null) {
+			path1 = new File(".").toPath();
+		}
+		return path1.resolve(path2);
+	}
+}