Package org.apache.catalina.loader

Class StandardClassLoader

  • All Implemented Interfaces:
    Closeable, AutoCloseable, Reloader
    public class StandardClassLoader
extends URLClassLoader
implements Reloader
    Subclass implementation of java.net.URLClassLoader that knows how to load classes from disk directories, as well as local and remote JAR files. It also implements the Reloader interface, to provide automatic reloading support to the associated loader.

    In all cases, URLs must conform to the contract specified by URLClassLoader - any URL that ends with a "/" character is assumed to represent a directory; all other URLs are assumed to be the address of a JAR file.

    IMPLEMENTATION NOTE - Local repositories are searched in the order they are added via the initial constructor and/or any subsequent calls to addRepository().

    IMPLEMENTATION NOTE - At present, there are no dependencies from this class to any other Catalina class, so that it could be used independently.

    Version:
    $Revision: 1.3 $ $Date: 2006/03/12 01:27:02 $
    Author:
    Craig R. McClanahan, Remy Maucherat

    • Field Detail

      • debug

        protected int debug
        The debugging detail level of this component.

      • delegate

        protected boolean delegate
        Should this class loader delegate to the parent class loader before searching its own repositories (i.e. the usual Java2 delegation model)? If set to false, this class loader will search its own repositories first, and delegate to the parent only if the class or resource is not found locally.

      • repositories

        protected ArrayList<String> repositories
        The list of local repositories, in the order they should be searched for locally loaded classes or resources.

    • Constructor Detail

      • StandardClassLoader

        public StandardClassLoader()
        Construct a new ClassLoader with no defined repositories and no parent ClassLoader.

      • StandardClassLoader

        public StandardClassLoader​(URLStreamHandlerFactory factory)
        Construct a new ClassLoader with no defined repositories and no parent ClassLoader, but with a stream handler factory.
        Parameters:
        factory - the URLStreamHandlerFactory to use when creating URLs

      • StandardClassLoader

        public StandardClassLoader​(ClassLoader parent)
        Construct a new ClassLoader with no defined repositories and the specified parent ClassLoader.
        Parameters:
        parent - The parent ClassLoader

      • StandardClassLoader

        public StandardClassLoader​(ClassLoader parent,
                           URLStreamHandlerFactory factory)
        Construct a new ClassLoader with no defined repositories and the specified parent ClassLoader.
        Parameters:
        parent - The parent ClassLoader
        factory - the URLStreamHandlerFactory to use when creating URLs

      • StandardClassLoader

        public StandardClassLoader​(String[] repositories)
        Construct a new ClassLoader with the specified repositories and no parent ClassLoader.
        Parameters:
        repositories - The initial set of repositories

      • StandardClassLoader

        public StandardClassLoader​(String[] repositories,
                           ClassLoader parent)
        Construct a new ClassLoader with the specified repositories and parent ClassLoader.
        Parameters:
        repositories - The initial set of repositories
        parent - The parent ClassLoader

      • StandardClassLoader

        public StandardClassLoader​(URL[] repositories)
        Construct a new ClassLoader with the specified repositories and no parent ClassLoader.
        Parameters:
        repositories - The initial set of repositories

      • StandardClassLoader

        public StandardClassLoader​(URL[] repositories,
                           ClassLoader parent)
        Construct a new ClassLoader with the specified repositories and parent ClassLoader.
        Parameters:
        repositories - The initial set of repositories
        parent - The parent ClassLoader

    • Method Detail

      • getDebug

        public int getDebug()
        Return the debugging detail level for this component.

      • setDebug

        public void setDebug​(int debug)
        Set the debugging detail level for this component.
        Parameters:
        debug - The new debugging detail level

      • getDelegate

        public boolean getDelegate()
        Return the "delegate first" flag for this class loader.

      • setDelegate

        public void setDelegate​(boolean delegate)
        Set the "delegate first" flag for this class loader.
        Parameters:
        delegate - The new "delegate first" flag

      • setPermissions

        protected void setPermissions​(String path)
        If there is a Java SecurityManager create a read FilePermission or JndiPermission for the file directory path.
        Parameters:
        path - file directory path

      • setPermissions

        protected void setPermissions​(URL url)
        If there is a Java SecurityManager add a read FilePermission or JndiPermission for URL.
        Parameters:
        url - URL for a file or directory on local system

      • addRepository

        public void addRepository​(String repository)
        Add a new repository to the set of places this ClassLoader can look for classes to be loaded.
        Specified by:
        addRepository in interface Reloader
        Parameters:
        repository - Name of a source of classes to be loaded, such as a directory pathname, a JAR file pathname, or a ZIP file pathname
        Throws:
        IllegalArgumentException - if the specified repository is invalid or does not exist

      • modified

        public boolean modified()
        This class loader doesn't check for reloading.
        Specified by:
        modified in interface Reloader

      • toString

        public String toString()
        Render a String representation of this object.
        Overrides:
        toString in class Object

      • findResource

        public URL findResource​(String name)
        Find the specified resource in our local repository, and return a URL refering to it, or null if this resource cannot be found.
        Overrides:
        findResource in class URLClassLoader
        Parameters:
        name - Name of the resource to be found

      • findResources

        public Enumeration<URL> findResources​(String name)
                               throws IOException
        Return an enumeration of URLs representing all of the resources with the given name. If no resources with this name are found, return an empty enumeration.
        Overrides:
        findResources in class URLClassLoader
        Parameters:
        name - Name of the resources to be found
        Throws:
        IOException - if an input/output error occurs

      • getResource

        public URL getResource​(String name)
        Find the resource with the given name. A resource is some data (images, audio, text, etc.) that can be accessed by class code in a way that is independent of the location of the code. The name of a resource is a "/"-separated path name that identifies the resource. If the resource cannot be found, return null.

        This method searches according to the following algorithm, returning as soon as it finds the appropriate URL. If the resource cannot be found, returns null.

        • If the delegate property is set to true, call the getResource() method of the parent class loader, if any.
        • Call findResource() to find this resource in our locally defined repositories.
        • Call the getResource() method of the parent class loader, if any.
        Overrides:
        getResource in class ClassLoader
        Parameters:
        name - Name of the resource to return a URL for

      • getResourceAsStream

        public InputStream getResourceAsStream​(String name)
        Find the resource with the given name, and return an input stream that can be used for reading it. The search order is as described for getResource(), after checking to see if the resource data has been previously cached. If the resource cannot be found, return null.
        Overrides:
        getResourceAsStream in class URLClassLoader
        Parameters:
        name - Name of the resource to return an input stream for

      • loadClass

        public Class loadClass​(String name)
                throws ClassNotFoundException
        Load the class with the specified name. This method searches for classes in the same manner as loadClass(String, boolean) with false as the second argument.
        Overrides:
        loadClass in class ClassLoader
        Parameters:
        name - Name of the class to be loaded
        Throws:
        ClassNotFoundException - if the class was not found

      • loadClass

        public Class loadClass​(String name,
                       boolean resolve)
                throws ClassNotFoundException
        Load the class with the specified name, searching using the following algorithm until it finds and returns the class. If the class cannot be found, returns ClassNotFoundException.
        • Call findLoadedClass(String) to check if the class has already been loaded. If it has, the same Class object is returned.
        • If the delegate property is set to true, call the loadClass() method of the parent class loader, if any.
        • Call findClass() to find this class in our locally defined repositories.
        • Call the loadClass() method of our parent class loader, if any.
        If the class was found using the above steps, and the resolve flag is true, this method will then call resolveClass(Class) on the resulting Class object.
        Overrides:
        loadClass in class ClassLoader
        Parameters:
        name - Name of the class to be loaded
        resolve - If true then resolve the class
        Throws:
        ClassNotFoundException - if the class was not found

      • getPermissions

        protected final PermissionCollection getPermissions​(CodeSource codeSource)
        Get the Permissions for a CodeSource. If this instance of StandardClassLoader is for a web application context, add read FilePermissions for the base directory (if unpacked), the context URL, and jar file resources.
        Overrides:
        getPermissions in class URLClassLoader
        Parameters:
        codeSource - where the code was loaded from
        Returns:
        PermissionCollection for CodeSource

      • parseProtocol

        protected static String parseProtocol​(String spec)
        Parse URL protocol.
        Returns:
        String protocol

      • addRepositoryInternal

        protected void addRepositoryInternal​(String repository)
        Add a repository to our internal array only.
        Parameters:
        repository - The new repository
        Throws:
        IllegalArgumentException - if the manifest of a JAR file cannot be processed correctly

      • convert

        protected static URL[] convert​(String[] input)
        Convert an array of String to an array of URL and return it.
        Parameters:
        input - The array of String to be converted

      • convert

        protected static URL[] convert​(String[] input,
                               URLStreamHandlerFactory factory)
        Convert an array of String to an array of URL and return it.
        Parameters:
        input - The array of String to be converted
        factory - Handler factory to use to generate the URLs

      • findLoadedResource

        protected InputStream findLoadedResource​(String name)
        Finds the resource with the given name if it has previously been loaded and cached by this class loader, and return an input stream to the resource data. If this resource has not been cached, return null.
        Parameters:
        name - Name of the resource to return