leap.lang.resource.ClassPathResource Maven / Gradle / Ivy
/*
* Copyright 2002-2010 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 leap.lang.resource;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Objects;
import leap.lang.Args;
import leap.lang.Classes;
import leap.lang.path.Paths;
/**
* {@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
* @see java.lang.ClassLoader#getResourceAsStream(String)
* @see java.lang.Class#getResourceAsStream(String)
*/
public class ClassPathResource extends AbstractFileResolvingResource {
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)
* @see org.springframework.util.ClassUtils#getDefaultClassLoader()
*/
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) {
Args.notNull(path, "path");
String pathToUse = Paths.normalize(path);
if (pathToUse.startsWith("/")) {
pathToUse = pathToUse.substring(1);
}
this.path = pathToUse;
this.classLoader = (classLoader != null ? classLoader : Classes.getClassLoader());
}
/**
* 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) {
Args.notNull(path, "path");
this.path = Paths.normalize(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 = Paths.normalize(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());
}
/**
* This implementation checks for the resolution of a resource URL.
* @see java.lang.ClassLoader#getResource(String)
* @see java.lang.Class#getResource(String)
*/
@Override
public boolean exists() {
URL url;
if (this.clazz != null) {
url = this.clazz.getResource(this.path);
}
else {
url = this.classLoader.getResource(this.path);
}
return (url != null);
}
/**
* 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;
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;
}
/**
* This implementation returns a URL for the underlying class path resource.
* @see java.lang.ClassLoader#getResource(String)
* @see java.lang.Class#getResource(String)
*/
@Override
public URL getURL() throws IOException {
URL url;
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;
}
/**
* This implementation creates a ClassPathResource, applying the given path
* relative to the path of the underlying resource of this descriptor.
* @see org.springframework.util.StringUtils#applyRelative(String, String)
*/
@Override
public Resource createRelative(String relativePath) {
String pathToUse = Paths.applyRelative(this.path, relativePath);
return new ClassPathResource(pathToUse, this.classLoader, this.clazz);
}
/**
* This implementation returns the name of the file that this class path
* resource refers to.
* @see org.springframework.util.StringUtils#getFileName(String)
*/
@Override
public String getFilename() {
return Paths.getFileName(this.path);
}
/**
* This implementation returns a description that includes the class path location.
*/
public String getDescription() {
StringBuilder builder = new StringBuilder("class path resource [");
if (this.clazz != null) {
builder.append(Classes.getPackageResourcePath(this.clazz));
builder.append('/');
}
builder.append(this.path);
builder.append(']');
return builder.toString();
}
/**
* This implementation compares the underlying class path locations.
*/
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (obj instanceof ClassPathResource) {
ClassPathResource otherRes = (ClassPathResource) obj;
return (this.path.equals(otherRes.path) &&
Objects.equals(this.classLoader, otherRes.classLoader) &&
Objects.equals(this.clazz, otherRes.clazz));
}
return false;
}
/**
* This implementation returns the hash code of the underlying
* class path location.
*/
@Override
public int hashCode() {
return this.path.hashCode();
}
@Override
public String getClasspath() {
return path;
}
@Override
public String toString() {
return "classpath:" + path;
}
}