/*
* 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 org.springframework.core.io.support;
import org.springframework.core.io.ResourceLoader;
import org.springframework.util.Assert;
import org.springframework.util.ResourceUtils;
/**
* Utility class for determining whether a given URL is a resource
* location that can be loaded via a ResourcePatternResolver.
*
* <p>Callers will usually assume that a location is a relative path
* if the {@link #isUrl(String)} method returns <code>false</code>.
*
* @author Juergen Hoeller
* @since 1.2.3
*/
public abstract class ResourcePatternUtils {
/**
* Return whether the given resource location is a URL: either a
* special "classpath" or "classpath*" pseudo URL or a standard URL.
* @param resourceLocation the location String to check
* @return whether the location qualifies as a URL
* @see ResourcePatternResolver#CLASSPATH_ALL_URL_PREFIX
* @see org.springframework.util.ResourceUtils#CLASSPATH_URL_PREFIX
* @see org.springframework.util.ResourceUtils#isUrl(String)
* @see java.net.URL
*/
public static boolean isUrl(String resourceLocation) {
return (resourceLocation != null &&
(resourceLocation.startsWith(ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX) ||
ResourceUtils.isUrl(resourceLocation)));
}
/**
* Return a default ResourcePatternResolver for the given ResourceLoader.
* <p>This might be the ResourceLoader itself, if it implements the
* ResourcePatternResolver extension, or a PathMatchingResourcePatternResolver
* built on the given ResourceLoader.
* @param resourceLoader the ResourceLoader to build a pattern resolver for
* (may be <code>null</code> to indicate a default ResourceLoader)
* @return the ResourcePatternResolver
* @see PathMatchingResourcePatternResolver
*/
public static ResourcePatternResolver getResourcePatternResolver(ResourceLoader resourceLoader) {
Assert.notNull(resourceLoader, "ResourceLoader must not be null");
if (resourceLoader instanceof ResourcePatternResolver) {
return (ResourcePatternResolver) resourceLoader;
}
else if (resourceLoader != null) {
return new PathMatchingResourcePatternResolver(resourceLoader);
}
else {
return new PathMatchingResourcePatternResolver();
}
}
}
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