org.datayoo.moql.util.ResourceUtils Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.datayoo.moql.util;
import org.apache.commons.lang3.StringUtils;
import java.io.File;
import java.io.FileNotFoundException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
/**
*
* @author Tang Tadin
*
*/
public abstract class ResourceUtils {
public static final String PREFIX_SEPARATOR = ":";
/** Pseudo URL prefix for loading from the class path: "classpath:" */
public static final String CLASSPATH_URL_PREFIX = "classpath:";
/** URL prefix for loading from the file system: "file:" */
public static final String FILE_URL_PREFIX = "file:";
/** URL protocol for a file in the file system: "file" */
public static final String URL_PROTOCOL_FILE = "file";
/** URL protocol for an entry from a jar file: "jar" */
public static final String URL_PROTOCOL_JAR = "jar";
/** URL protocol for an entry from a zip file: "zip" */
public static final String URL_PROTOCOL_ZIP = "zip";
/** Separator between JAR URL and file path within the JAR */
public static final String JAR_URL_SEPARATOR = "!/";
/**
* Resolve the given resource location to a java.net.URL.
*
* Does not check whether the URL actually exists; simply returns the URL
* that the given location would correspond to.
*
* @param resourceLocation the resource location to resolve: either a "classpath:" pseudo
* URL, a "file:" URL, or a plain file path
* @return a corresponding URL object
* @throws FileNotFoundException
* if the resource cannot be resolved to a URL
*/
public static URL getURL(String resourceLocation)
throws FileNotFoundException {
if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {
String path = resourceLocation.substring(CLASSPATH_URL_PREFIX.length());
URL url = ClassLoaderUtils.getDefaultClassLoader().getResource(path);
if (url == null) {
throw new FileNotFoundException(StringFormater.format(
"Resource location '{}'"
+ "cannot be resolved to URL because it does not exist!",
resourceLocation));
}
return url;
}
try {
// try URL
return new URL(resourceLocation);
} catch (MalformedURLException ex) {
// no URL -> treat as file path
try {
return new File(resourceLocation).toURI().toURL();
} catch (MalformedURLException ex2) {
throw new FileNotFoundException(StringFormater.format(
"Resource location '{}'"
+ " is neither a URL not a well-formed file path",
resourceLocation));
}
}
}
/**
* Resolve the given resource location to a java.io.File, i.e.
* to a file in the file system.
*
* Does not check whether the file actually exists; simply returns the File
* that the given location would correspond to.
*
* @param resourceLocation the resource location to resolve: either a "classpath:" pseudo
* URL, a "file:" URL, or a plain file path
* @return a corresponding File object
* @throws FileNotFoundException
* if the resource cannot be resolved to a file in the file
* system
*/
public static File getFile(String resourceLocation)
throws FileNotFoundException {
if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {
String path = resourceLocation.substring(CLASSPATH_URL_PREFIX.length());
URL url = ClassLoaderUtils.getDefaultClassLoader().getResource(path);
if (url == null) {
throw new FileNotFoundException(StringFormater.format(
"'{}' cannot be resolved to absolute file path "
+ "because it does not reside in the file system",
resourceLocation));
}
return getFile(url);
}
try {
// try URL
return getFile(new URL(resourceLocation));
} catch (MalformedURLException ex) {
// no URL -> treat as file path
return new File(resourceLocation);
}
}
/**
* Resolve the given resource URL to a java.io.File, i.e. to a
* file in the file system.
*
* @param resourceUrl the resource URL to resolve
* @return a corresponding File object
* @throws FileNotFoundException
* if the URL cannot be resolved to a file in the file system
*/
public static File getFile(URL resourceUrl) throws FileNotFoundException {
if (!URL_PROTOCOL_FILE.equals(resourceUrl.getProtocol())) {
throw new FileNotFoundException(StringFormater.format(
"'{}' cannot be resolved to absolute file path "
+ "because it does not reside in the file system",
resourceUrl.toString()));
}
try {
return new File(toURI(resourceUrl).getSchemeSpecificPart());
} catch (URISyntaxException ex) {
// Fallback for URLs that are not valid URIs (should hardly ever
// happen).
return new File(resourceUrl.getFile());
}
}
/**
* Resolve the given resource URI to a java.io.File, i.e. to a
* file in the file system.
*
* @param resourceUri the resource URI to resolve
* @return a corresponding File object
* @throws FileNotFoundException
* if the URL cannot be resolved to a file in the file system
*/
public static File getFile(URI resourceUri) throws FileNotFoundException {
if (!URL_PROTOCOL_FILE.equals(resourceUri.getScheme())) {
throw new FileNotFoundException(StringFormater.format(
"'{}' cannot be resolved to absolute file path "
+ "because it does not reside in the file system",
resourceUri.toString()));
}
return new File(resourceUri.getSchemeSpecificPart());
}
/**
* Return whether the given resource location is a URL: either a special
* "classpath" pseudo URL or a standard URL.
*
* @param resourceLocation the location String to check
* @return whether the location qualifies as a URL
*/
public static boolean isUrl(String resourceLocation) {
if (resourceLocation == null) {
return false;
}
if (resourceLocation.startsWith(CLASSPATH_URL_PREFIX)) {
return true;
}
try {
new URL(resourceLocation);
return true;
} catch (MalformedURLException ex) {
return false;
}
}
/**
* Determine whether the given URL points to a resource in a jar file, that
* is, has protocol "jar", "zip".
*
* @param url the URL to check
* @return whether the URL has been identified as a JAR URL
*/
public static boolean isJarURL(URL url) {
String protocol = url.getProtocol();
return (URL_PROTOCOL_JAR.equals(protocol) || URL_PROTOCOL_ZIP
.equals(protocol));
}
/**
* Extract the URL for the actual jar file from the given URL (which may
* point to a resource in a jar file or to a jar file itself).
*
* @param jarUrl the original URL
* @return the URL for the actual jar file
* @throws MalformedURLException
* if no valid jar file URL could be extracted
*/
public static URL extractJarFileURL(URL jarUrl) throws MalformedURLException {
String urlFile = jarUrl.getFile();
int separatorIndex = urlFile.indexOf(JAR_URL_SEPARATOR);
if (separatorIndex != -1) {
return new URL(urlFile.substring(0, separatorIndex));
} else {
return jarUrl;
}
}
/**
* Create a URI instance for the given URL, replacing spaces with "%20"
* quotes first.
*
* Furthermore, this method works on JDK 1.4 as well, in contrast to the
* URL.toURI() method.
*
* @param url the URL to convert into a URI instance
* @return the URI instance
* @throws URISyntaxException
* if the URL wasn't a valid URI
*/
public static URI toURI(URL url) throws URISyntaxException {
return toURI(url.toString());
}
/**
* Create a URI instance for the given location String, replacing spaces
* with "%20" quotes first.
*
* @param location the location String to convert into a URI instance
* @return the URI instance
* @throws URISyntaxException
* if the location wasn't a valid URI
*/
public static URI toURI(String location) throws URISyntaxException {
return new URI(StringUtils.replace(location, " ", "%20"));
}
}