org.nanoframework.commons.io.ClassPathResource Maven / Gradle / Ivy
/*
* Copyright 2015-2016 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.nanoframework.commons.io;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import org.nanoframework.commons.util.Assert;
import org.nanoframework.commons.util.ClassUtils;
import org.nanoframework.commons.util.ObjectUtils;
import org.nanoframework.commons.util.ResourceUtils;
import org.nanoframework.commons.util.StringUtils;
/**
* {@link Resource} implementation for class path resources.
* Uses either a given ClassLoader or a given Class for loading resources.
*
* Supports resolution as java.io.File 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.ClassLoader#getResourceAsStream(String)
* @see java.lang.Class#getResourceAsStream(String)
*/
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.
*
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(String)
*/
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(String)
*/
public ClassPathResource(String path, ClassLoader classLoader) {
Assert.notNull(path, "Path must not be null");
String pathToUse = StringUtils.cleanPath(path);
if (pathToUse.startsWith("/")) {
pathToUse = pathToUse.substring(1);
}
this.path = pathToUse;
this.classLoader = (classLoader != null ? classLoader : ClassUtils.getDefaultClassLoader());
}
/**
* 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 must not be null");
this.path = StringUtils.cleanPath(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) {
this.path = StringUtils.cleanPath(path);
this.classLoader = classLoader;
this.clazz = clazz;
}
/**
* @return the path for this resource (as resource path within the class path).
*/
public final String getPath() {
return this.path;
}
/**
* @return the ClassLoader that this resource will be obtained from.
*/
public final ClassLoader getClassLoader() {
return (this.classLoader != null ? this.classLoader : this.clazz.getClassLoader());
}
/**
* @return This implementation opens an InputStream for the given class path resource.
* @see java.lang.ClassLoader#getResourceAsStream(String)
* @see java.lang.Class#getResourceAsStream(String)
*/
public InputStream getInputStream() throws IOException {
InputStream is = null;
if (this.clazz != null) {
is = this.clazz.getResourceAsStream(this.path);
} else {
is = this.classLoader.getResourceAsStream(this.path);
}
if (is == null) {
throw new FileNotFoundException(getDescription() + " cannot be opened because it does not exist");
}
return is;
}
/**
* @return This implementation returns a URL for the underlying class path resource.
* @see java.lang.ClassLoader#getResource(String)
* @see java.lang.Class#getResource(String)
*/
public URL getURL() throws IOException {
URL url = null;
if (this.clazz != null) {
url = this.clazz.getResource(this.path);
} else {
url = this.classLoader.getResource(this.path);
}
if (url == null) {
throw new FileNotFoundException(getDescription() + " cannot be resolved to URL because it does not exist");
}
return url;
}
/**
* @return This implementation returns a File reference for the underlying class path
* resource, provided that it refers to a file in the file system.
*/
public File getFile() throws IOException {
return ResourceUtils.getFile(getURL(), getDescription());
}
/**
* @reutnr This implementation determines the underlying File
* (or jar file, in case of a resource in a jar/zip).
*/
protected File getFileForLastModifiedCheck() throws IOException {
URL url = getURL();
if (ResourceUtils.isJarURL(url)) {
URL actualUrl = ResourceUtils.extractJarFileURL(url);
return ResourceUtils.getFile(actualUrl);
} else {
return ResourceUtils.getFile(url, getDescription());
}
}
/**
* @return This implementation creates a ClassPathResource, applying the given path
* relative to the path of the underlying resource of this descriptor.
*/
public Resource createRelative(String relativePath) {
String pathToUse = StringUtils.applyRelativePath(this.path, relativePath);
return new ClassPathResource(pathToUse, this.classLoader, this.clazz);
}
/**
* @return This implementation returns the name of the file that this class path
* resource refers to.
*/
public String getFilename() {
return StringUtils.getFilename(this.path);
}
/**
* @return This implementation returns a description that includes the class path location.
*/
public String getDescription() {
return "class path resource [" + this.path + ']';
}
/**
* @return This implementation compares the underlying class path locations.
*/
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.classLoader, otherRes.classLoader)
&& ObjectUtils.nullSafeEquals(this.clazz, otherRes.clazz));
}
return false;
}
/**
* @return This implementation returns the hash code of the underlying
* class path location.
*/
public int hashCode() {
return this.path.hashCode();
}
}