com.wl4g.infra.common.resource.resolver.DefaultResourceLoader Maven / Gradle / Ivy
/*
* Copyright 2017 ~ 2025 the original author or authors. James Wong
*
* 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 com.wl4g.infra.common.resource.resolver;
/**
* Retention of upstream license agreement statement:
* Thank you very much spring framework, We fully comply with and support the open license
* agreement of spring. The purpose of migration is to solve the problem
* that these elegant API programs can still be easily used without running
* in the spring environment.
*
* Copyright 2002-2017 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.
*/
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Collection;
import java.util.LinkedHashSet;
import java.util.Set;
import com.wl4g.infra.common.lang.Assert2;
import com.wl4g.infra.common.lang.ClassUtils2;
import com.wl4g.infra.common.lang.StringUtils2;
import com.wl4g.infra.common.resource.ClassPathStreamResource;
import com.wl4g.infra.common.resource.StreamResource;
import com.wl4g.infra.common.resource.UrlStreamResource;
/**
* Default implementation of the {@link ResourceLoader} interface. Used by
* {@link ResourceEditor}, and serves as base class for
* {@link org.springframework.context.support.AbstractApplicationContext}. Can
* also be used standalone.
*
*
* Will return a {@link UrlStreamResource} if the location value is a URL, and a
* {@link ClassPathStreamResource} if it is a non-URL path or a "classpath:"
* pseudo-URL.
*
* @author Juergen Hoeller
* @since 10.03.2004
* @see FileSystemResourceLoader
* @see org.springframework.context.support.ClassPathXmlApplicationContext
*/
public class DefaultResourceLoader implements ResourceLoader {
private ClassLoader classLoader;
private final Set protocolResolvers = new LinkedHashSet(4);
/**
* Create a new DefaultResourceLoader.
*
* ClassLoader access will happen using the thread context class loader at
* the time of this ResourceLoader's initialization.
*
* @see java.lang.Thread#getContextClassLoader()
*/
public DefaultResourceLoader() {
this.classLoader = ClassUtils2.getDefaultClassLoader();
}
/**
* Create a new DefaultResourceLoader.
*
* @param classLoader
* the ClassLoader to load class path resources with, or
* {@code null} for using the thread context class loader at the
* time of actual resource access
*/
public DefaultResourceLoader(ClassLoader classLoader) {
this.classLoader = classLoader;
}
/**
* Specify the ClassLoader to load class path resources with, or
* {@code null} for using the thread context class loader at the time of
* actual resource access.
*
* The default is that ClassLoader access will happen using the thread
* context class loader at the time of this ResourceLoader's initialization.
*/
public void setClassLoader(ClassLoader classLoader) {
this.classLoader = classLoader;
}
/**
* Return the ClassLoader to load class path resources with.
*
* Will get passed to ClassPathResource's constructor for all
* ClassPathResource objects created by this resource loader.
*
* @see ClassPathStreamResource
*/
@Override
public ClassLoader getClassLoader() {
return (this.classLoader != null ? this.classLoader : ClassUtils2.getDefaultClassLoader());
}
/**
* Register the given resolver with this resource loader, allowing for
* additional protocols to be handled.
*
* Any such resolver will be invoked ahead of this loader's standard
* resolution rules. It may therefore also override any default rules.
*
* @since 4.3
* @see #getProtocolResolvers()
*/
public void addProtocolResolver(ProtocolResolver resolver) {
Assert2.notNull(resolver, "ProtocolResolver must not be null");
this.protocolResolvers.add(resolver);
}
/**
* Return the collection of currently registered protocol resolvers,
* allowing for introspection as well as modification.
*
* @since 4.3
*/
public Collection getProtocolResolvers() {
return this.protocolResolvers;
}
@Override
public StreamResource getResource(String location) {
Assert2.notNull(location, "Location must not be null");
for (ProtocolResolver protocolResolver : this.protocolResolvers) {
StreamResource resource = protocolResolver.resolve(location, this);
if (resource != null) {
return resource;
}
}
if (location.startsWith("/")) {
return getResourceByPath(location);
} else if (location.startsWith(CLASSPATH_URL_PREFIX)) {
return new ClassPathStreamResource(location.substring(CLASSPATH_URL_PREFIX.length()), getClassLoader());
} else {
try {
// Try to parse the location as a URL...
URL url = new URL(location);
return new UrlStreamResource(url);
} catch (MalformedURLException ex) {
// No URL -> resolve as resource path.
return getResourceByPath(location);
}
}
}
/**
* Return a Resource handle for the resource at the given path.
*
* The default implementation supports class path locations. This should be
* appropriate for standalone implementations but can be overridden, e.g.
* for implementations targeted at a Servlet container.
*
* @param path
* the path to the resource
* @return the corresponding Resource handle
* @see ClassPathStreamResource
* @see org.springframework.context.support.FileSystemXmlApplicationContext#getResourceByPath
* @see org.springframework.web.context.support.XmlWebApplicationContext#getResourceByPath
*/
protected StreamResource getResourceByPath(String path) {
return new ContextClassPathStreamResource(path, getClassLoader());
}
/**
* ClassPathResource that explicitly expresses a context-relative path
* through implementing the ContextResource interface.
*/
protected static class ContextClassPathStreamResource extends ClassPathStreamResource {
public ContextClassPathStreamResource(String path, ClassLoader classLoader) {
super(path, classLoader);
}
public String getPathWithinContext() {
return getPath();
}
@Override
public StreamResource createRelative(String relativePath) {
String pathToUse = StringUtils2.applyRelativePath(getPath(), relativePath);
return new ContextClassPathStreamResource(pathToUse, getClassLoader());
}
}
}