ResourceLoader.java

package com.firefly.utils.io;

import com.firefly.utils.ResourceUtils;

/**
 * Strategy interface for loading resources (e.. class path or file system
 * resources).
 *
 *
 * <p>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.
 *
 */
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.
	 * The handle should always be a reusable resource descriptor,
	 * allowing for multiple {@link Resource#getInputStream()} calls.
	 * <p><ul>
	 * <li>Must support fully qualified URLs, e.g. "file:C:/test.dat".
	 * <li>Must support classpath pseudo-URLs, e.g. "classpath:test.dat".
	 * <li>Should support relative file paths, e.g. "WEB-INF/test.dat".
	 * (This will be implementation-specific, typically provided by an
	 * ApplicationContext implementation.)
	 * </ul>
	 * <p>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
	 * @see #CLASSPATH_URL_PREFIX
	 */
	Resource getResource(String location);

	/**
	 * Expose the ClassLoader used by this ResourceLoader.
	 * <p>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)
	 */
	ClassLoader getClassLoader();

}