/*
 * Copyright 1999,2004 The Apache Software Foundation.
 *
 * 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.apache.naming.resources;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.Hashtable;

import javax.naming.NameAlreadyBoundException;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.OperationNotSupportedException;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;
import javax.naming.directory.ModificationItem;
import javax.naming.directory.SearchControls;

import org.apache.naming.NamingContextBindingsEnumeration;
import org.apache.naming.NamingContextEnumeration;
import org.apache.naming.NamingEntry;

/**
 * Filesystem Directory Context implementation helper class.
 *
 * @author Remy Maucherat
 * @version $Revision$ $Date$
 */

public class FileDirContext extends BaseDirContext {

    private static org.apache.commons.logging.Log log=
        org.apache.commons.logging.LogFactory.getLog( FileDirContext.class );

    // -------------------------------------------------------------- Constants


    /**
     * The descriptive information string for this implementation.
     */
    protected static final int BUFFER_SIZE = 2048;


    // ----------------------------------------------------------- Constructors


    /**
     * Builds a file directory context using the given environment.
     */
    public FileDirContext() {
        super();
    }


    /**
     * Builds a file directory context using the given environment.
     */
    public FileDirContext(Hashtable env) {
        super(env);
    }


    // ----------------------------------------------------- Instance Variables


    /**
     * The document base directory.
     */
    protected File base = null;


    /**
     * Absolute normalized filename of the base.
     */
    protected String absoluteBase = null;


    /**
     * Case sensitivity.
     */
    protected boolean caseSensitive = true;


    /**
     * Allow linking.
     */
    protected boolean allowLinking = false;


    // ------------------------------------------------------------- Properties


    /**
     * Set the document root.
     *
     * @param docBase The new document root
     *
     * @exception IllegalArgumentException if the specified value is not
     *  supported by this implementation
     * @exception IllegalArgumentException if this would create a
     *  malformed URL
     */
    public void setDocBase(String docBase) {

    // Validate the format of the proposed document root
    if (docBase == null)
        throw new IllegalArgumentException
        (sm.getString("resources.null"));

    // Calculate a File object referencing this document base directory
    base = new File(docBase);
        try {
            base = base.getCanonicalFile();
        } catch (IOException e) {
            // Ignore
        }

    // Validate that the document base is an existing directory
    if (!base.exists() || !base.isDirectory() || !base.canRead())
        throw new IllegalArgumentException
        (sm.getString("fileResources.base", docBase));
        this.absoluteBase = base.getAbsolutePath();
        super.setDocBase(docBase);

    }


    /**
     * Set case sensitivity.
     */
    public void setCaseSensitive(boolean caseSensitive) {
        this.caseSensitive = caseSensitive;
    }


    /**
     * Is case sensitive ?
     */
    public boolean isCaseSensitive() {
        return caseSensitive;
    }


    /**
     * Set allow linking.
     */
    public void setAllowLinking(boolean allowLinking) {
        this.allowLinking = allowLinking;
    }


    /**
     * Is linking allowed.
     */
    public boolean getAllowLinking() {
        return allowLinking;
    }


    // --------------------------------------------------------- Public Methods


    /**
     * Release any resources allocated for this directory context.
     */
    public void release() {

        caseSensitive = true;
        allowLinking = false;
        absoluteBase = null;
        base = null;
        super.release();

    }


    // -------------------------------------------------------- Context Methods


    /**
     * Retrieves the named object.
     *
     * @param name the name of the object to look up
     * @return the object bound to name
     * @exception NamingException if a naming exception is encountered
     */
    public Object lookup(String name)
        throws NamingException {
        Object result = null;
        File file = file(name);

        if (file == null)
            throw new NamingException
                (sm.getString("resources.notFound", name));

        if (file.isDirectory()) {
            FileDirContext tempContext = new FileDirContext(env);
            tempContext.setDocBase(file.getPath());
            tempContext.setAllowLinking(getAllowLinking());
            tempContext.setCaseSensitive(isCaseSensitive());
            result = tempContext;
        } else {
            result = new FileResource(file);
        }

        return result;

    }


    /**
     * Unbinds the named object. Removes the terminal atomic name in name
     * from the target context--that named by all but the terminal atomic
     * part of name.
     * <p>
     * This method is idempotent. It succeeds even if the terminal atomic
     * name is not bound in the target context, but throws
     * NameNotFoundException if any of the intermediate contexts do not exist.
     *
     * @param name the name to bind; may not be empty
     * @exception NameNotFoundException if an intermediate context does not
     * exist
     * @exception NamingException if a naming exception is encountered
     */
    public void unbind(String name)
        throws NamingException {

        File file = file(name);

        if (file == null)
            throw new NamingException
                (sm.getString("resources.notFound", name));

        if (!file.delete())
            throw new NamingException
                (sm.getString("resources.unbindFailed", name));

    }


    /**
     * Binds a new name to the object bound to an old name, and unbinds the
     * old name. Both names are relative to this context. Any attributes
     * associated with the old name become associated with the new name.
     * Intermediate contexts of the old name are not changed.
     *
     * @param oldName the name of the existing binding; may not be empty
     * @param newName the name of the new binding; may not be empty
     * @exception NameAlreadyBoundException if newName is already bound
     * @exception NamingException if a naming exception is encountered
     */
    public void rename(String oldName, String newName)
        throws NamingException {

        File file = file(oldName);

        if (file == null)
            throw new NamingException
                (sm.getString("resources.notFound", oldName));

        File newFile = new File(base, newName);

        file.renameTo(newFile);

    }


    /**
     * Enumerates the names bound in the named context, along with the class
     * names of objects bound to them. The contents of any subcontexts are
     * not included.
     * <p>
     * If a binding is added to or removed from this context, its effect on
     * an enumeration previously returned is undefined.
     *
     * @param name the name of the context to list
     * @return an enumeration of the names and class names of the bindings in
     * this context. Each element of the enumeration is of type NameClassPair.
     * @exception NamingException if a naming exception is encountered
     */
    public NamingEnumeration list(String name)
        throws NamingException {

        File file = file(name);

        if (file == null)
            throw new NamingException
                (sm.getString("resources.notFound", name));

        return new NamingContextEnumeration(list(file).iterator());

    }


    /**
     * Enumerates the names bound in the named context, along with the
     * objects bound to them. The contents of any subcontexts are not
     * included.
     * <p>
     * If a binding is added to or removed from this context, its effect on
     * an enumeration previously returned is undefined.
     *
     * @param name the name of the context to list
     * @return an enumeration of the bindings in this context.
     * Each element of the enumeration is of type Binding.
     * @exception NamingException if a naming exception is encountered
     */
    public NamingEnumeration listBindings(String name)
        throws NamingException {

        File file = file(name);

        if (file == null)
            throw new NamingException
                (sm.getString("resources.notFound", name));

        return new NamingContextBindingsEnumeration(list(file).iterator(),
                this);

    }


    /**
     * Destroys the named context and removes it from the namespace. Any
     * attributes associated with the name are also removed. Intermediate
     * contexts are not destroyed.
     * <p>
     * This method is idempotent. It succeeds even if the terminal atomic
     * name is not bound in the target context, but throws
     * NameNotFoundException if any of the intermediate contexts do not exist.
     *
     * In a federated naming system, a context from one naming system may be
     * bound to a name in another. One can subsequently look up and perform
     * operations on the foreign context using a composite name. However, an
     * attempt destroy the context using this composite name will fail with
     * NotContextException, because the foreign context is not a "subcontext"
     * of the context in which it is bound. Instead, use unbind() to remove
     * the binding of the foreign context. Destroying the foreign context
     * requires that the destroySubcontext() be performed on a context from
     * the foreign context's "native" naming system.
     *
     * @param name the name of the context to be destroyed; may not be empty
     * @exception NameNotFoundException if an intermediate context does not
     * exist
     * @exception NotContextException if the name is bound but does not name
     * a context, or does not name a context of the appropriate type
     */
    public void destroySubcontext(String name)
        throws NamingException {
        unbind(name);
    }


    /**
     * Retrieves the named object, following links except for the terminal
     * atomic component of the name. If the object bound to name is not a
     * link, returns the object itself.
     *
     * @param name the name of the object to look up
     * @return the object bound to name, not following the terminal link
     * (if any).
     * @exception NamingException if a naming exception is encountered
     */
    public Object lookupLink(String name)
        throws NamingException {
        // Note : Links are not supported
        return lookup(name);
    }


    /**
     * Retrieves the full name of this context within its own namespace.
     * <p>
     * Many naming services have a notion of a "full name" for objects in
     * their respective namespaces. For example, an LDAP entry has a
     * distinguished name, and a DNS record has a fully qualified name. This
     * method allows the client application to retrieve this name. The string
     * returned by this method is not a JNDI composite name and should not be
     * passed directly to context methods. In naming systems for which the
     * notion of full name does not make sense,
     * OperationNotSupportedException is thrown.
     *
     * @return this context's name in its own namespace; never null
     * @exception OperationNotSupportedException if the naming system does
     * not have the notion of a full name
     * @exception NamingException if a naming exception is encountered
     */
    public String getNameInNamespace()
        throws NamingException {
        return docBase;
    }


    // ----------------------------------------------------- DirContext Methods


    /**
     * Retrieves selected attributes associated with a named object.
     * See the class description regarding attribute models, attribute type
     * names, and operational attributes.
     *
     * @return the requested attributes; never null
     * @param name the name of the object from which to retrieve attributes
     * @param attrIds the identifiers of the attributes to retrieve. null
     * indicates that all attributes should be retrieved; an empty array
     * indicates that none should be retrieved
     * @exception NamingException if a naming exception is encountered
     */
    public Attributes getAttributes(String name, String[] attrIds)
        throws NamingException {

        // Building attribute list
        File file = file(name);

        if (file == null)
            throw new NamingException
                (sm.getString("resources.notFound", name));

        return new FileResourceAttributes(file);

    }


    /**
     * Modifies the attributes associated with a named object. The order of
     * the modifications is not specified. Where possible, the modifications
     * are performed atomically.
     *
     * @param name the name of the object whose attributes will be updated
     * @param mod_op the modification operation, one of: ADD_ATTRIBUTE,
     * REPLACE_ATTRIBUTE, REMOVE_ATTRIBUTE
     * @param attrs the attributes to be used for the modification; may not
     * be null
     * @exception AttributeModificationException if the modification cannot be
     * completed successfully
     * @exception NamingException if a naming exception is encountered
     */
    public void modifyAttributes(String name, int mod_op, Attributes attrs)
        throws NamingException {

    }


    /**
     * Modifies the attributes associated with a named object using an an
     * ordered list of modifications. The modifications are performed in the
     * order specified. Each modification specifies a modification operation
     * code and an attribute on which to operate. Where possible, the
     * modifications are performed atomically.
     *
     * @param name the name of the object whose attributes will be updated
     * @param mods an ordered sequence of modifications to be performed; may
     * not be null
     * @exception AttributeModificationException if the modification cannot be
     * completed successfully
     * @exception NamingException if a naming exception is encountered
     */
    public void modifyAttributes(String name, ModificationItem[] mods)
        throws NamingException {

    }


    /**
     * Binds a name to an object, along with associated attributes. If attrs
     * is null, the resulting binding will have the attributes associated
     * with obj if obj is a DirContext, and no attributes otherwise. If attrs
     * is non-null, the resulting binding will have attrs as its attributes;
     * any attributes associated with obj are ignored.
     *
     * @param name the name to bind; may not be empty
     * @param obj the object to bind; possibly null
     * @param attrs the attributes to associate with the binding
     * @exception NameAlreadyBoundException if name is already bound
     * @exception InvalidAttributesException if some "mandatory" attributes
     * of the binding are not supplied
     * @exception NamingException if a naming exception is encountered
     */
    public void bind(String name, Object obj, Attributes attrs)
        throws NamingException {

        // Note: No custom attributes allowed

        File file = new File(base, name);
        if (file.exists())
            throw new NameAlreadyBoundException
                (sm.getString("resources.alreadyBound", name));

        rebind(name, obj, attrs);

    }


    /**
     * Binds a name to an object, along with associated attributes,
     * overwriting any existing binding. If attrs is null and obj is a
     * DirContext, the attributes from obj are used. If attrs is null and obj
     * is not a DirContext, any existing attributes associated with the object
     * already bound in the directory remain unchanged. If attrs is non-null,
     * any existing attributes associated with the object already bound in
     * the directory are removed and attrs is associated with the named
     * object. If obj is a DirContext and attrs is non-null, the attributes
     * of obj are ignored.
     *
     * @param name the name to bind; may not be empty
     * @param obj the object to bind; possibly null
     * @param attrs the attributes to associate with the binding
     * @exception InvalidAttributesException if some "mandatory" attributes
     * of the binding are not supplied
     * @exception NamingException if a naming exception is encountered
     */
    public void rebind(String name, Object obj, Attributes attrs)
        throws NamingException {

        // Note: No custom attributes allowed
        // Check obj type

        File file = new File(base, name);

        InputStream is = null;
        if (obj instanceof Resource) {
            try {
                is = ((Resource) obj).streamContent();
            } catch (IOException e) {
            }
        } else if (obj instanceof InputStream) {
            is = (InputStream) obj;
        } else if (obj instanceof DirContext) {
            if (file.exists()) {
                if (!file.delete())
                    throw new NamingException
                        (sm.getString("resources.bindFailed", name));
            }
            if (!file.mkdir())
                throw new NamingException
                    (sm.getString("resources.bindFailed", name));
        }
        if (is == null)
            throw new NamingException
                (sm.getString("resources.bindFailed", name));

        // Open os

        try {
            FileOutputStream os = null;
            byte buffer[] = new byte[BUFFER_SIZE];
            int len = -1;
            try {
                os = new FileOutputStream(file);
                while (true) {
                    len = is.read(buffer);
                    if (len == -1)
                        break;
                    os.write(buffer, 0, len);
                }
            } finally {
                if (os != null)
                    os.close();
                is.close();
            }
        } catch (IOException e) {
            throw new NamingException
                (sm.getString("resources.bindFailed", e));
        }

    }


    /**
     * Creates and binds a new context, along with associated attributes.
     * This method creates a new subcontext with the given name, binds it in
     * the target context (that named by all but terminal atomic component of
     * the name), and associates the supplied attributes with the newly
     * created object. All intermediate and target contexts must already
     * exist. If attrs is null, this method is equivalent to
     * Context.createSubcontext().
     *
     * @param name the name of the context to create; may not be empty
     * @param attrs the attributes to associate with the newly created context
     * @return the newly created context
     * @exception NameAlreadyBoundException if the name is already bound
     * @exception InvalidAttributesException if attrs does not contain all
     * the mandatory attributes required for creation
     * @exception NamingException if a naming exception is encountered
     */
    public DirContext createSubcontext(String name, Attributes attrs)
        throws NamingException {

        File file = new File(base, name);
        if (file.exists())
            throw new NameAlreadyBoundException
                (sm.getString("resources.alreadyBound", name));
        if (!file.mkdir())
            throw new NamingException
                (sm.getString("resources.bindFailed", name));
        return (DirContext) lookup(name);

    }


    /**
     * Retrieves the schema associated with the named object. The schema
     * describes rules regarding the structure of the namespace and the
     * attributes stored within it. The schema specifies what types of
     * objects can be added to the directory and where they can be added;
     * what mandatory and optional attributes an object can have. The range
     * of support for schemas is directory-specific.
     *
     * @param name the name of the object whose schema is to be retrieved
     * @return the schema associated with the context; never null
     * @exception OperationNotSupportedException if schema not supported
     * @exception NamingException if a naming exception is encountered
     */
    public DirContext getSchema(String name)
        throws NamingException {
        throw new OperationNotSupportedException();
    }


    /**
     * Retrieves a context containing the schema objects of the named
     * object's class definitions.
     *
     * @param name the name of the object whose object class definition is to
     * be retrieved
     * @return the DirContext containing the named object's class
     * definitions; never null
     * @exception OperationNotSupportedException if schema not supported
     * @exception NamingException if a naming exception is encountered
     */
    public DirContext getSchemaClassDefinition(String name)
        throws NamingException {
        throw new OperationNotSupportedException();
    }


    /**
     * Searches in a single context for objects that contain a specified set
     * of attributes, and retrieves selected attributes. The search is
     * performed using the default SearchControls settings.
     *
     * @param name the name of the context to search
     * @param matchingAttributes the attributes to search for. If empty or
     * null, all objects in the target context are returned.
     * @param attributesToReturn the attributes to return. null indicates
     * that all attributes are to be returned; an empty array indicates that
     * none are to be returned.
     * @return a non-null enumeration of SearchResult objects. Each
     * SearchResult contains the attributes identified by attributesToReturn
     * and the name of the corresponding object, named relative to the
     * context named by name.
     * @exception NamingException if a naming exception is encountered
     */
    public NamingEnumeration search(String name, Attributes matchingAttributes,
                                    String[] attributesToReturn)
        throws NamingException {
        return null;
    }


    /**
     * Searches in a single context for objects that contain a specified set
     * of attributes. This method returns all the attributes of such objects.
     * It is equivalent to supplying null as the atributesToReturn parameter
     * to the method search(Name, Attributes, String[]).
     *
     * @param name the name of the context to search
     * @param matchingAttributes the attributes to search for. If empty or
     * null, all objects in the target context are returned.
     * @return a non-null enumeration of SearchResult objects. Each
     * SearchResult contains the attributes identified by attributesToReturn
     * and the name of the corresponding object, named relative to the
     * context named by name.
     * @exception NamingException if a naming exception is encountered
     */
    public NamingEnumeration search(String name, Attributes matchingAttributes)
        throws NamingException {
        return null;
    }


    /**
     * Searches in the named context or object for entries that satisfy the
     * given search filter. Performs the search as specified by the search
     * controls.
     *
     * @param name the name of the context or object to search
     * @param filter the filter expression to use for the search; may not be
     * null
     * @param cons the search controls that control the search. If null,
     * the default search controls are used (equivalent to
     * (new SearchControls())).
     * @return an enumeration of SearchResults of the objects that satisfy
     * the filter; never null
     * @exception InvalidSearchFilterException if the search filter specified
     * is not supported or understood by the underlying directory
     * @exception InvalidSearchControlsException if the search controls
     * contain invalid settings
     * @exception NamingException if a naming exception is encountered
     */
    public NamingEnumeration search(String name, String filter,
                                    SearchControls cons)
        throws NamingException {
        return null;
    }


    /**
     * Searches in the named context or object for entries that satisfy the
     * given search filter. Performs the search as specified by the search
     * controls.
     *
     * @param name the name of the context or object to search
     * @param filterExpr the filter expression to use for the search.
     * The expression may contain variables of the form "{i}" where i is a
     * nonnegative integer. May not be null.
     * @param filterArgs the array of arguments to substitute for the
     * variables in filterExpr. The value of filterArgs[i] will replace each
     * occurrence of "{i}". If null, equivalent to an empty array.
     * @param cons the search controls that control the search. If null, the
     * default search controls are used (equivalent to (new SearchControls())).
     * @return an enumeration of SearchResults of the objects that satisy the
     * filter; never null
     * @exception ArrayIndexOutOfBoundsException if filterExpr contains {i}
     * expressions where i is outside the bounds of the array filterArgs
     * @exception InvalidSearchControlsException if cons contains invalid
     * settings
     * @exception InvalidSearchFilterException if filterExpr with filterArgs
     * represents an invalid search filter
     * @exception NamingException if a naming exception is encountered
     */
    public NamingEnumeration search(String name, String filterExpr,
                                    Object[] filterArgs, SearchControls cons)
        throws NamingException {
        return null;
    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Return a context-relative path, beginning with a "/", that represents
     * the canonical version of the specified path after ".." and "." elements
     * are resolved out.  If the specified path attempts to go outside the
     * boundaries of the current context (i.e. too many ".." path elements
     * are present), return <code>null</code> instead.
     *
     * @param path Path to be normalized
     */
    protected String normalize(String path) {

    String normalized = path;

    // Normalize the slashes and add leading slash if necessary
    if (File.separatorChar == '\\' && normalized.indexOf('\\') >= 0)
        normalized = normalized.replace('\\', '/');
    if (!normalized.startsWith("/"))
        normalized = "/" + normalized;

    // Resolve occurrences of "//" in the normalized path
    while (true) {
        int index = normalized.indexOf("//");
        if (index < 0)
        break;
        normalized = normalized.substring(0, index) +
        normalized.substring(index + 1);
    }

    // Resolve occurrences of "/./" in the normalized path
    while (true) {
        int index = normalized.indexOf("/./");
        if (index < 0)
        break;
        normalized = normalized.substring(0, index) +
        normalized.substring(index + 2);
    }

    // Resolve occurrences of "/../" in the normalized path
    while (true) {
        int index = normalized.indexOf("/../");
        if (index < 0)
        break;
        if (index == 0)
        return (null);  // Trying to go outside our context
        int index2 = normalized.lastIndexOf('/', index - 1);
        normalized = normalized.substring(0, index2) +
        normalized.substring(index + 3);
    }

    // Return the normalized path that we have completed
    return (normalized);

    }


    /**
     * Return a File object representing the specified normalized
     * context-relative path if it exists and is readable.  Otherwise,
     * return <code>null</code>.
     *
     * @param name Normalized context-relative path (with leading '/')
     */
    protected File file(String name) {

        File file = new File(base, name);
        if (file.exists() && file.canRead()) {

        	if (allowLinking)
        		return file;
        	
            // Check that this file belongs to our root path
            String canPath = null;
            try {
                canPath = file.getCanonicalPath();
            } catch (IOException e) {
            }
            if (canPath == null)
                return null;

            // Bugzilla 38154: after release() the absoluteBase is null, leading to an NPE
            if (absoluteBase == null) {
                return null;
            }

            // Check to see if going outside of the web application root
            if (!canPath.startsWith(absoluteBase)) {
                return null;
            }

            // Case sensitivity check
            if (caseSensitive) {
                String fileAbsPath = file.getAbsolutePath();
                if (fileAbsPath.endsWith("."))
                    fileAbsPath = fileAbsPath + "/";
                String absPath = normalize(fileAbsPath);
                if (canPath != null)
                    canPath = normalize(canPath);
                if ((absoluteBase.length() < absPath.length())
                    && (absoluteBase.length() < canPath.length())) {
                    absPath = absPath.substring(absoluteBase.length() + 1);
                    if ((canPath == null) || (absPath == null))
                        return null;
                    if (absPath.equals(""))
                        absPath = "/";
                    canPath = canPath.substring(absoluteBase.length() + 1);
                    if (canPath.equals(""))
                        canPath = "/";
                    if (!canPath.equals(absPath))
                        return null;
                }
            }

        } else {
            return null;
        }
        return file;

    }


    /**
     * List the resources which are members of a collection.
     *
     * @param file Collection
     * @return Vector containg NamingEntry objects
     */
    protected ArrayList list(File file) {

        ArrayList entries = new ArrayList();
        if (!file.isDirectory())
            return entries;
        String[] names = file.list();
        if (names==null) {
            /* Some IO error occurred such as bad file permissions.
               Prevent a NPE with Arrays.sort(names) */
            log.warn(sm.getString("fileResources.listingNull",
                                  file.getAbsolutePath()));
            return entries;
        }

        Arrays.sort(names);             // Sort alphabetically
        if (names == null)
            return entries;
        NamingEntry entry = null;

        for (int i = 0; i < names.length; i++) {

            File currentFile = new File(file, names[i]);
            Object object = null;
            if (currentFile.isDirectory()) {
                FileDirContext tempContext = new FileDirContext(env);
                tempContext.setDocBase(file.getPath());
                tempContext.setAllowLinking(getAllowLinking());
                tempContext.setCaseSensitive(isCaseSensitive());
                object = tempContext;
            } else {
                object = new FileResource(currentFile);
            }
            entry = new NamingEntry(names[i], object, NamingEntry.ENTRY);
            entries.add(entry);

        }

        return entries;

    }


    // ----------------------------------------------- FileResource Inner Class


    /**
     * This specialized resource implementation avoids opening the IputStream
     * to the file right away (which would put a lock on the file).
     */
    protected class FileResource extends Resource {


        // -------------------------------------------------------- Constructor


        public FileResource(File file) {
            this.file = file;
        }


        // --------------------------------------------------- Member Variables


        /**
         * Associated file object.
         */
        protected File file;


        /**
         * File length.
         */
        protected long length = -1L;


        // --------------------------------------------------- Resource Methods


        /**
         * Content accessor.
         *
         * @return InputStream
         */
        public InputStream streamContent()
            throws IOException {
            if (binaryContent == null) {
                inputStream = new FileInputStream(file);
            }
            return super.streamContent();
        }


    }


    // ------------------------------------- FileResourceAttributes Inner Class


    /**
     * This specialized resource attribute implementation does some lazy
     * reading (to speed up simple checks, like checking the last modified
     * date).
     */
    protected class FileResourceAttributes extends ResourceAttributes {


        // -------------------------------------------------------- Constructor


        public FileResourceAttributes(File file) {
            this.file = file;
        }

        // --------------------------------------------------- Member Variables


        protected File file;


        protected boolean accessed = false;


        protected String canonicalPath = null;


        // ----------------------------------------- ResourceAttributes Methods


        /**
         * Is collection.
         */
        public boolean isCollection() {
            if (!accessed) {
                collection = file.isDirectory();
                accessed = true;
            }
            return super.isCollection();
        }


        /**
         * Get content length.
         *
         * @return content length value
         */
        public long getContentLength() {
            if (contentLength != -1L)
                return contentLength;
            contentLength = file.length();
            return contentLength;
        }


        /**
         * Get creation time.
         *
         * @return creation time value
         */
        public long getCreation() {
            if (creation != -1L)
                return creation;
            creation = file.lastModified();
            return creation;
        }


        /**
         * Get creation date.
         *
         * @return Creation date value
         */
        public Date getCreationDate() {
            if (creation == -1L) {
                creation = file.lastModified();
            }
            return super.getCreationDate();
        }


        /**
         * Get last modified time.
         *
         * @return lastModified time value
         */
        public long getLastModified() {
            if (lastModified != -1L)
                return lastModified;
            lastModified = file.lastModified();
            return lastModified;
        }


        /**
         * Get lastModified date.
         *
         * @return LastModified date value
         */
        public Date getLastModifiedDate() {
            if (lastModified == -1L) {
                lastModified = file.lastModified();
            }
            return super.getLastModifiedDate();
        }


        /**
         * Get name.
         *
         * @return Name value
         */
        public String getName() {
            if (name == null)
                name = file.getName();
            return name;
        }


        /**
         * Get resource type.
         *
         * @return String resource type
         */
        public String getResourceType() {
            if (!accessed) {
                collection = file.isDirectory();
                accessed = true;
            }
            return super.getResourceType();
        }

        
        /**
         * Get canonical path.
         * 
         * @return String the file's canonical path
         */
        public String getCanonicalPath() {
            if (canonicalPath == null) {
                try {
                    canonicalPath = file.getCanonicalPath();
                } catch (IOException e) {
                    // Ignore
                }
            }
            return canonicalPath;
        }
        

    }


}