Package nl.basjes.parse.useragent.utils.springframework.core.io.support

Class PathMatchingResourcePatternResolver

java.lang.Object
nl.basjes.parse.useragent.utils.springframework.core.io.support.PathMatchingResourcePatternResolver
All Implemented Interfaces:
ResourceLoader, ResourcePatternResolver
public class PathMatchingResourcePatternResolver extends Object implements ResourcePatternResolver
A {link ResourcePatternResolver} implementation that is able to resolve a specified resource location path into one or more matching Resources. The source path may be a simple path which has a one-to-one mapping to a target {link org.springframework.core.io.Resource}, or alternatively may contain the special "classpath*:" prefix and/or internal Ant-style regular expressions (matched using Spring's {link org.springframework.util.AntPathMatcher} utility). Both of the latter are effectively wildcards.

No Wildcards:

In the simple case, if the specified location path does not start with the "classpath*:" prefix, and does not contain a PathMatcher pattern, this resolver will simply return a single resource via a getResource() call on the underlying ResourceLoader. Examples are real URLs such as "file:C:/context.xml", pseudo-URLs such as "classpath:/context.xml", and simple unprefixed paths such as "/WEB-INF/context.xml". The latter will resolve in a fashion specific to the underlying ResourceLoader (e.g. ServletContextResource for a WebApplicationContext).

Ant-style Patterns:

When the path location contains an Ant-style pattern, e.g.: 

 /WEB-INF/*-context.xml
 com/mycompany/**/applicationContext.xml
 file:C:/some/path/*-context.xml
 classpath:com/mycompany/**/applicationContext.xml
the resolver follows a more complex but defined procedure to try to resolve the wildcard. It produces a Resource for the path up to the last non-wildcard segment and obtains a URL from it. If this URL is not a "jar:" URL or container-specific variant (e.g. "zip:" in WebLogic, "wsjar" in WebSphere", etc.), then a java.io.File is obtained from it, and used to resolve the wildcard by walking the filesystem. In the case of a jar URL, the resolver either gets a java.net.JarURLConnection from it, or manually parses the jar URL, and then traverses the contents of the jar file, to resolve the wildcards.

Implications on portability:

If the specified path is already a file URL (either explicitly, or implicitly because the base ResourceLoader is a filesystem one), then wildcarding is guaranteed to work in a completely portable fashion.

If the specified path is a classpath location, then the resolver must obtain the last non-wildcard path segment URL via a Classloader.getResource() call. Since this is just a node of the path (not the file at the end) it is actually undefined (in the ClassLoader Javadocs) exactly what sort of URL is returned in this case. In practice, it is usually a java.io.File representing the directory, where the classpath resource resolves to a filesystem location, or a jar URL of some sort, where the classpath resource resolves to a jar location. Still, there is a portability concern on this operation.

If a jar URL is obtained for the last non-wildcard segment, the resolver must be able to get a java.net.JarURLConnection from it, or manually parse the jar URL, to be able to walk the contents of the jar, and resolve the wildcard. This will work in most environments, but will fail in others, and it is strongly recommended that the wildcard resolution of resources coming from jars be thoroughly tested in your specific environment before you rely on it.

classpath*: Prefix:

There is special support for retrieving multiple class path resources with the same name, via the "classpath*:" prefix. For example, "classpath*:META-INF/beans.xml" will find all "beans.xml" files in the class path, be it in "classes" directories or in JAR files. This is particularly useful for autodetecting config files of the same name at the same location within each jar file. Internally, this happens via a ClassLoader.getResources() call, and is completely portable.

The "classpath*:" prefix can also be combined with a PathMatcher pattern in the rest of the location path, for example "classpath*:META-INF/*-beans.xml". In this case, the resolution strategy is fairly simple: a ClassLoader.getResources() call is used on the last non-wildcard path segment to get all the matching resources in the class loader hierarchy, and then off each resource the same PathMatcher resolution strategy described above is used for the wildcard subpath.

Other notes:

WARNING: Note that "classpath*:" when combined with Ant-style patterns will only work reliably with at least one root directory before the pattern starts, unless the actual target files reside in the file system. This means that a pattern like "classpath*:*.xml" will not retrieve files from the root of jar files but rather only from the root of expanded directories. This originates from a limitation in the JDK's ClassLoader.getResources() method which only returns file system locations for a passed-in empty String (indicating potential roots to search). This ResourcePatternResolver implementation is trying to mitigate the jar root lookup limitation through {link URLClassLoader} introspection and "java.class.path" manifest evaluation; however, without portability guarantees.

WARNING: Ant-style patterns with "classpath:" resources are not guaranteed to find matching resources if the root package to search is available in multiple class path locations. This is because a resource such as 

     com/mycompany/package1/service-context.xml
may be in only one location, but when a path such as 
     classpath:com/mycompany/**/service-context.xml
is used to try to resolve it, the resolver will work off the (first) URL returned by getResource("com/mycompany");. If this base package node exists in multiple classloader locations, the actual end resource may not be underneath. Therefore, preferably, use "classpath*:" with the same Ant-style pattern in such a case, which will search all class path locations that contain the root package.
Since:
1.0.2
Author:
Juergen Hoeller, Colin Sampaleanu, Marius Bogoevici, Costin Leau, Phillip Webb see #CLASSPATH_ALL_URL_PREFIX see org.springframework.util.AntPathMatcher see org.springframework.core.io.ResourceLoader#getResource(String) see ClassLoader#getResources(String)

  • Constructor Details

    • PathMatchingResourcePatternResolver

      public PathMatchingResourcePatternResolver()
      Create a new PathMatchingResourcePatternResolver with a DefaultResourceLoader.

      ClassLoader access will happen via the thread context class loader. see org.springframework.core.io.DefaultResourceLoader

    • PathMatchingResourcePatternResolver

      public PathMatchingResourcePatternResolver(@Nullable ClassLoader classLoader)
      Create a new PathMatchingResourcePatternResolver with a DefaultResourceLoader.
      Parameters:
      classLoader - the ClassLoader to load classpath resources with, or null for using the thread context class loader at the time of actual resource access see org.springframework.core.io.DefaultResourceLoader

  • Method Details

    • getResourceLoader

      public ResourceLoader getResourceLoader()
      Return the ResourceLoader that this pattern resolver works with.

    • getClassLoader

      @Nullable public ClassLoader getClassLoader()
      Description copied from interface: ResourceLoader
      Expose the {link 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.

      Specified by:
      getClassLoader in interface ResourceLoader
      Returns:
      the ClassLoader (only null if even the system ClassLoader isn't accessible) see org.springframework.util.ClassUtils#getDefaultClassLoader() see org.springframework.util.ClassUtils#forName(String, ClassLoader)

    • getPathMatcher

      public PathMatcher getPathMatcher()
      Return the PathMatcher that this resource pattern resolver uses.

    • getResource

      public Resource getResource(String location)
      Description copied from interface: ResourceLoader
      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.

      Specified by:
      getResource in interface ResourceLoader
      Parameters:
      location - the resource location
      Returns:
      a corresponding Resource handle (never null) see #CLASSPATH_URL_PREFIX see Resource#exists() see Resource#getInputStream()

    • getResources

      public Resource[] getResources(String locationPattern) throws IOException
      Description copied from interface: ResourcePatternResolver
      Resolve the given location pattern into Resource objects.

      Overlapping resource entries that point to the same physical resource should be avoided, as far as possible. The result should have set semantics.

      Specified by:
      getResources in interface ResourcePatternResolver
      Parameters:
      locationPattern - the location pattern to resolve
      Returns:
      the corresponding Resource objects
      Throws:
      IOException - in case of I/O errors

    • findAllClassPathResources

      protected Resource[] findAllClassPathResources(String location) throws IOException
      Find all class location resources with the given location via the ClassLoader. Delegates to {link #doFindAllClassPathResources(String)}.
      Parameters:
      location - the absolute path within the classpath
      Returns:
      the result as Resource array
      Throws:
      IOException - in case of I/O errors see java.lang.ClassLoader#getResources see #convertClassLoaderURL

    • doFindAllClassPathResources

      protected Set<Resource> doFindAllClassPathResources(String path) throws IOException
      Find all class location resources with the given path via the ClassLoader. Called by {link #findAllClassPathResources(String)}.
      Parameters:
      path - the absolute path within the classpath (never a leading slash)
      Returns:
      a mutable Set of matching Resource instances
      Throws:
      IOException
      Since:
      4.1.1

    • convertClassLoaderURL

      protected Resource convertClassLoaderURL(URL url)
      Convert the given URL as returned from the ClassLoader into a {link Resource}.

      The default implementation simply creates a {link UrlResource} instance.

      Parameters:
      url - a URL as returned from the ClassLoader
      Returns:
      the corresponding Resource object see java.lang.ClassLoader#getResources see org.springframework.core.io.Resource

    • addAllClassLoaderJarRoots

      protected void addAllClassLoaderJarRoots(@Nullable ClassLoader classLoader, Set<Resource> result)
      Search all {link URLClassLoader} URLs for jar file references and add them to the given set of resources in the form of pointers to the root of the jar file content.
      Parameters:
      classLoader - the ClassLoader to search (including its ancestors)
      result - the set of resources to add jar roots to
      Since:
      4.1.1

    • addClassPathManifestEntries

      protected void addClassPathManifestEntries(Set<Resource> result)
      Determine jar file references from the "java.class.path." manifest property and add them to the given set of resources in the form of pointers to the root of the jar file content.
      Parameters:
      result - the set of resources to add jar roots to
      Since:
      4.3

    • findPathMatchingResources

      protected Resource[] findPathMatchingResources(String locationPattern) throws IOException
      Find all resources that match the given location pattern via the Ant-style PathMatcher. Supports resources in jar files and zip files and in the file system.
      Parameters:
      locationPattern - the location pattern to match
      Returns:
      the result as Resource array
      Throws:
      IOException - in case of I/O errors see #doFindPathMatchingJarResources see #doFindPathMatchingFileResources see org.springframework.util.PathMatcher

    • determineRootDir

      protected String determineRootDir(String location)
      Determine the root directory for the given location.

      Used for determining the starting point for file matching, resolving the root directory location to a java.io.File and passing it into retrieveMatchingFiles, with the remainder of the location as pattern.

      Will return "/WEB-INF/" for the pattern "/WEB-INF/*.xml", for example.

      Parameters:
      location - the location to check
      Returns:
      the part of the location that denotes the root directory see #retrieveMatchingFiles

    • resolveRootDirResource

      protected Resource resolveRootDirResource(Resource original) throws IOException
      Resolve the specified resource for path matching.

      By default, Equinox OSGi "bundleresource:" / "bundleentry:" URL will be resolved into a standard jar file URL that be traversed using Spring's standard jar file traversal algorithm. For any preceding custom resolution, override this method and replace the resource handle accordingly.

      Parameters:
      original - the resource to resolve
      Returns:
      the resolved resource (may be identical to the passed-in resource)
      Throws:
      IOException - in case of resolution failure

    • doFindPathMatchingJarResources

      protected Set<Resource> doFindPathMatchingJarResources(Resource rootDirResource, URL rootDirURL, String subPattern) throws IOException
      Find all resources in jar files that match the given location pattern via the Ant-style PathMatcher.
      Parameters:
      rootDirResource - the root directory as Resource
      rootDirURL - the pre-resolved root directory URL
      subPattern - the sub pattern to match (below the root directory)
      Returns:
      a mutable Set of matching Resource instances
      Throws:
      IOException - in case of I/O errors see java.net.JarURLConnection see org.springframework.util.PathMatcher
      Since:
      4.3

    • getJarFile

      protected JarFile getJarFile(String jarFileUrl) throws IOException
      Resolve the given jar file URL into a JarFile object.
      Throws:
      IOException

    • doFindPathMatchingFileResources

      protected Set<Resource> doFindPathMatchingFileResources(Resource rootDirResource, String subPattern) throws IOException
      Find all resources in the file system that match the given location pattern via the Ant-style PathMatcher.
      Parameters:
      rootDirResource - the root directory as Resource
      subPattern - the sub pattern to match (below the root directory)
      Returns:
      a mutable Set of matching Resource instances
      Throws:
      IOException - in case of I/O errors see #retrieveMatchingFiles see org.springframework.util.PathMatcher

    • doFindMatchingFileSystemResources

      protected Set<Resource> doFindMatchingFileSystemResources(File rootDir, String subPattern) throws IOException
      Find all resources in the file system that match the given location pattern via the Ant-style PathMatcher.
      Parameters:
      rootDir - the root directory in the file system
      subPattern - the sub pattern to match (below the root directory)
      Returns:
      a mutable Set of matching Resource instances
      Throws:
      IOException - in case of I/O errors see #retrieveMatchingFiles see org.springframework.util.PathMatcher

    • retrieveMatchingFiles

      protected Set<File> retrieveMatchingFiles(File rootDir, String pattern) throws IOException
      Retrieve files that match the given path pattern, checking the given directory and its subdirectories.
      Parameters:
      rootDir - the directory to start from
      pattern - the pattern to match against, relative to the root directory
      Returns:
      a mutable Set of matching Resource instances
      Throws:
      IOException - if directory contents could not be retrieved

    • doRetrieveMatchingFiles

      protected void doRetrieveMatchingFiles(String fullPattern, File dir, Set<File> result) throws IOException
      Recursively retrieve files that match the given pattern, adding them to the given result list.
      Parameters:
      fullPattern - the pattern to match against, with prepended root directory path
      dir - the current directory
      result - the Set of matching File instances to add to
      Throws:
      IOException - if directory contents could not be retrieved

    • listDirectory

      protected File[] listDirectory(File dir)
      Determine a sorted list of files in the given directory.
      Parameters:
      dir - the directory to introspect
      Returns:
      the sorted list of files (by default in alphabetical order) see File#listFiles()
      Since:
      5.1