001/*
002 * ModeShape (http://www.modeshape.org)
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *       http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.modeshape.common.util;
017
018import java.io.InputStream;
019
020/**
021 * Utility to search and load resources from the CP.
022 *
023 * @author Horia Chiorean (hchiorea@redhat.com)
024 */
025public final class ResourceLookup {
026
027    private ResourceLookup() {
028    }
029
030    /**
031     * Returns the stream of a resource at a given path, using some optional class loaders.
032     *
033     * @param path the path to search
034     * @param classLoader a {@link java.lang.ClassLoader} instance to use when searching; may be null.
035     * @param useTLCL {@code true} if the thread local class loader should be used as well, in addition to {@code classLoader}
036     * @return a {@link java.io.InputStream} if the resource was found, or {@code null} otherwise
037     */
038    public static InputStream read( String path, ClassLoader classLoader, boolean useTLCL ) {
039        if (useTLCL) {
040            InputStream stream = Thread.currentThread().getContextClassLoader().getResourceAsStream(path);
041            if (stream != null) {
042                return stream;
043            }
044        }
045        return classLoader != null ? classLoader.getResourceAsStream(path) : ResourceLookup.class.getResourceAsStream(path);
046    }
047
048    /**
049     * Returns the stream of a resource at a given path, using the CL of a class.
050     *
051     * @param path the path to search
052     * @param clazz a {@link java.lang.Class} instance which class loader should be used when doing the lookup.
053     * @param useTLCL {@code true} if the thread local class loader should be used as well, in addition to {@code classLoader}
054     * @return a {@link java.io.InputStream} if the resource was found, or {@code null} otherwise
055     * @see org.modeshape.common.util.ResourceLookup#read(String, ClassLoader, boolean)
056     */
057    public static InputStream read( String path, Class<?> clazz, boolean useTLCL ) {
058        return read(path, clazz.getClassLoader(), useTLCL);
059    }
060}