org.springframework.core.io.ResourceLoader Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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 org.springframework.lang.Nullable;
import org.springframework.util.ResourceUtils;
/**
* Strategy interface for loading resources (e.. class path or file system
* resources). An {@link org.springframework.context.ApplicationContext}
* is required to provide this functionality, plus extended
* {@link org.springframework.core.io.support.ResourcePatternResolver} support.
*
* {@link DefaultResourceLoader} is a standalone implementation that is
* usable outside an ApplicationContext, also used by {@link ResourceEditor}.
*
*
Bean properties of type Resource and Resource array can be populated
* from Strings when running in an ApplicationContext, using the particular
* context's resource loading strategy.
*
* @author Juergen Hoeller
* @since 10.03.2004
* @see Resource
* @see org.springframework.core.io.support.ResourcePatternResolver
* @see org.springframework.context.ApplicationContext
* @see org.springframework.context.ResourceLoaderAware
*/
public interface ResourceLoader {
/** Pseudo URL prefix for loading from the class path: "classpath:". */
String CLASSPATH_URL_PREFIX = ResourceUtils.CLASSPATH_URL_PREFIX;
/**
* Return a Resource handle for the specified resource location.
*
The handle should always be a reusable resource descriptor,
* allowing for multiple {@link Resource#getInputStream()} calls.
*
* - Must support fully qualified URLs, e.g. "file:C:/test.dat".
*
- Must support classpath pseudo-URLs, e.g. "classpath:test.dat".
*
- Should support relative file paths, e.g. "WEB-INF/test.dat".
* (This will be implementation-specific, typically provided by an
* ApplicationContext implementation.)
*
* Note that a Resource handle does not imply an existing resource;
* you need to invoke {@link Resource#exists} to check for existence.
* @param location the resource location
* @return a corresponding Resource handle (never {@code null})
* @see #CLASSPATH_URL_PREFIX
* @see Resource#exists()
* @see Resource#getInputStream()
*/
Resource getResource(String location);
/**
* Expose the ClassLoader used by this ResourceLoader.
*
Clients which need to access the ClassLoader directly can do so
* in a uniform manner with the ResourceLoader, rather than relying
* on the thread context ClassLoader.
* @return the ClassLoader
* (only {@code null} if even the system ClassLoader isn't accessible)
* @see org.springframework.util.ClassUtils#getDefaultClassLoader()
* @see org.springframework.util.ClassUtils#forName(String, ClassLoader)
*/
@Nullable
ClassLoader getClassLoader();
}