/* * Copyright (C) 2010 Google Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.clearsilver; import java.io.File; import java.util.LinkedList; import java.util.List; /** * Utility class containing helper methods */ public final class CSUtil { private CSUtil() { } public static final String HDF_LOADPATHS = "hdf.loadpaths"; /** * Helper function that returns a concatenation of the loadpaths in the * provided HDF. * @param hdf an HDF structure containing load paths. * @return A list of loadpaths in order in which to search. * @throws NullPointerException if no loadpaths are found. */ public static List getLoadPaths(HDF hdf) { return getLoadPaths(hdf, false); } /** * Helper function that returns a concatenation of the loadpaths in the * provided HDF. * @param hdf an HDF structure containing load paths. * @param allowEmpty if {@code true} then this will return an empty list when * no loadpaths are found in the HDF object, otherwise a * {@link NullPointerException} is thrown. Loadpaths are not needed if * no files are read in or are all specified by absolute paths. * @return A list of loadpaths in order in which to search. * @throws NullPointerException if no loadpaths are found and allowEmpty is * {@code false}. */ public static List getLoadPaths(HDF hdf, boolean allowEmpty) { List list = new LinkedList(); HDF loadpathsHdf = hdf.getObj(HDF_LOADPATHS); if (loadpathsHdf == null) { if (allowEmpty) { return list; } else { throw new NullPointerException("No HDF loadpaths located in the " + "specified HDF structure"); } } for (HDF lpHdf = loadpathsHdf.objChild(); lpHdf != null; lpHdf = lpHdf.objNext()) { list.add(lpHdf.objValue()); } return list; } /** * Given an ordered list of directories to look in, locate the specified file. * Returns null if file not found. * @param loadpaths the ordered list of paths to search. * @param filename the name of the file. * @return a File object corresponding to the file. null if * file not found. */ public static File locateFile(List loadpaths, String filename) { if (filename == null) { throw new NullPointerException("No filename provided"); } if (loadpaths == null) { throw new NullPointerException("No loadpaths provided."); } for (String path : loadpaths) { File file = new File(path, filename); if (file.exists()) { return file; } } return null; } }