Class: org.springframework.core.io.ClassPathResource   ©

/*
 * Copyright 2002-2004 the original author or authors.
 * 
 * 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.springframework.core.io;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;
import org.springframework.util.ResourceUtils;
import org.springframework.util.StringUtils;

/**
 * Resource implementation for class path resources.
 * Uses either the thread context class loader, a given ClassLoader
 * or a given Class for loading resources.
 *
 * <p>Supports resolution as <code>java.io.File</code> if the class path
 * resource resides in the file system, but not for resources in a JAR.
 * Always supports resolution as URL.
 *
 * @author Juergen Hoeller
 * @since 28.12.2003
 * @see java.lang.Thread#getContextClassLoader
 * @see java.lang.ClassLoader#getResourceAsStream
 * @see java.lang.Class#getResourceAsStream
 */
public class ClassPathResource extends AbstractResource {

    private final String path;

    private ClassLoader classLoader;

    private Class clazz;

    /**
     * Create a new ClassPathResource for ClassLoader usage.
     * A leading slash will be removed, as the ClassLoader
     * resource access methods will not accept it.
     * <p>The thread context class loader will be used for
     * loading the resource.
     * @param path the absolute path within the class path
     * @see java.lang.ClassLoader#getResourceAsStream
     * @see java.lang.Thread#getContextClassLoader
     */
    public ClassPathResource(String path) {
        this(path, (ClassLoader) null);
    }

    /**
     * Create a new ClassPathResource for ClassLoader usage.
     * A leading slash will be removed, as the ClassLoader
     * resource access methods will not accept it.
     * @param path the absolute path within the classpath
     * @param classLoader the class loader to load the resource with,
     * or null for the thread context class loader
     * @see java.lang.ClassLoader#getResourceAsStream
     */
    public ClassPathResource(String path, ClassLoader classLoader) {
        Assert.notNull(path, "path is required");
        if (path.startsWith("/")) {
            path = path.substring(1);
        }
        this.path = path;
        this.classLoader = classLoader;
    }

    /**
     * Create a new ClassPathResource for Class usage.
     * The path can be relative to the given class,
     * or absolute within the classpath via a leading slash.
     * @param path relative or absolute path within the class path
     * @param clazz the class to load resources with
     * @see java.lang.Class#getResourceAsStream
     */
    public ClassPathResource(String path, Class clazz) {
        Assert.notNull(path, "path is required");
        this.path = path;
        this.clazz = clazz;
    }

    /**
     * Create a new ClassPathResource with optional ClassLoader and Class.
     * Only for internal usage.
     * @param path relative or absolute path within the classpath
     * @param classLoader the class loader to load the resource with, if any
     * @param clazz the class to load resources with, if any
     */
    protected ClassPathResource(String path, ClassLoader classLoader, Class clazz) {
        Assert.notNull(path, "path is required");
        this.path = path;
        this.classLoader = classLoader;
        this.clazz = clazz;
    }

    public InputStream getInputStream() throws IOException {
        InputStream is = null;
        if (this.clazz != null) {
            is = this.clazz.getResourceAsStream(this.path);
        }
        else {
            ClassLoader cl = this.classLoader;
            if (cl == null) {
                // no class loader specified -> use thread context class loader
                cl = Thread.currentThread().getContextClassLoader();
            }
            is = cl.getResourceAsStream(this.path);
        }
        if (is == null) {
            throw new FileNotFoundException(
                    getDescription() + " cannot be opened because it does not exist");
        }
        return is;
    }

    public URL getURL() throws IOException {
        URL url = null;
        if (this.clazz != null) {
            url = this.clazz.getResource(this.path);
        }
        else {
            ClassLoader cl = this.classLoader;
            if (cl == null) {
                // no class loader specified -> use thread context class loader
                cl = Thread.currentThread().getContextClassLoader();
            }
            url = cl.getResource(this.path);
        }
        if (url == null) {
            throw new FileNotFoundException(
                    getDescription() + " cannot be resolved to URL because it does not exist");
        }
        return url;
    }

    public File getFile() throws IOException {
        return ResourceUtils.getFile(getURL(), getDescription());
    }

    public Resource createRelative(String relativePath) {
        String pathToUse = StringUtils.applyRelativePath(this.path, relativePath);
        return new ClassPathResource(pathToUse, this.classLoader, this.clazz);
    }

    public String getFilename() {
Rate        return StringUtils.getFilename(this.path);
    }

    public String getDescription() {
        return "class path resource [" + this.path + "]";
    }

    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (obj instanceof ClassPathResource) {
            ClassPathResource otherRes = (ClassPathResource) obj;
            return (this.path.equals(otherRes.path) && ObjectUtils.nullSafeEquals(this.clazz, otherRes.clazz));
        }
        return false;
    }

    public int hashCode() {
        return this.path.hashCode();
    }

}