org.jasig.maven.legal.util.ResourceFinder.java Source code

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Here is the source code for org.jasig.maven.legal.util.ResourceFinder.java

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/**
 * Licensed to Jasig under one or more contributor license
 * agreements. See the NOTICE file distributed with this work
 * for additional information regarding copyright ownership.
 * Jasig licenses this file to you 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.jasig.maven.legal.util;

import org.apache.maven.plugin.MojoFailureException;
import org.apache.maven.project.MavenProject;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.List;

/**
 * <b>Date:</b> 26-Feb-2008<br>
 * <b>Author:</b> Mathieu Carbou (mathieu.carbou@gmail.com)
 */
public final class ResourceFinder {
    private final MavenProject project;
    private CustomClassLoader compileClassPath;
    private CustomClassLoader pluginClassPath;

    public ResourceFinder(MavenProject project) {
        this.project = project;
    }

    public void setCompileClassPath(List<String> classpath) {
        compileClassPath = new CustomClassLoader();
        if (classpath != null) {
            for (String absolutePath : classpath) {
                compileClassPath.addFolder(absolutePath);
            }
        }
    }

    public void setPluginClassPath(ClassLoader classLoader) {
        pluginClassPath = new CustomClassLoader(classLoader);
    }

    /**
     * Find a resource by searching:<br/>
     * 1. In the filesystem, relative to basedir<br/>
     * 2. In the filesystem, as an absolute path (or relative to current execution directory)<br/>
     * 3. In project classpath<br/>
     * 4. In plugin classpath<br/>
     * 5. As a URL
     *
     * @param resource The resource to get
     * @return A valid URL
     * @throws MojoFailureException If the resource is not found
     */
    public URL findResource(String resource) throws MojoFailureException {
        // first search relatively to the base directory
        URL res = this.searchProjectTree(project, resource);
        if (res != null) {
            return res;
        }

        // if not found, search for absolute location on file system, or relative to execution dir
        res = toURL(new File(resource));
        if (res != null) {
            return res;
        }

        // if not found, try the classpaths
        String cpResource = resource.startsWith("/") ? resource.substring(1) : resource;

        // tries compile claspath of projet
        res = compileClassPath.getResource(cpResource);
        if (res != null) {
            return res;
        }

        // tries this plugin classpath
        res = pluginClassPath.getResource(cpResource);
        if (res != null) {
            return res;
        }

        // otherwise, tries to return a valid URL
        try {
            res = new URL(resource);
            res.openStream().close();
            return res;
        } catch (Exception e) {
        }

        throw new MojoFailureException("Resource not found in file system, classpath or URL: " + resource);
    }

    private URL searchProjectTree(MavenProject project, String resource) {
        // first search relatively to the base directory
        URL res = toURL(new File(project.getBasedir(), resource));
        if (res != null) {
            return res;
        }

        //Look up the project tree to try and find a match as well.
        final MavenProject parent = project.getParent();
        if (!project.isExecutionRoot() && parent != null && parent.getBasedir() != null) {
            return this.searchProjectTree(parent, resource);
        }

        return null;
    }

    private URL toURL(File file) {
        if (file.exists() && file.canRead()) {
            try {
                return file.toURI().toURL();
            } catch (MalformedURLException e) {
            }
        }
        return null;
    }

}