Tomcat example source code file (ApplicationContext.java)
The Tomcat ApplicationContext.java source code/*
* 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.apache.catalina.core;
import java.io.File;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import javax.naming.Binding;
import javax.naming.NamingException;
import javax.naming.directory.DirContext;
import javax.servlet.RequestDispatcher;
import javax.servlet.Servlet;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextAttributeEvent;
import javax.servlet.ServletContextAttributeListener;
import org.apache.catalina.Context;
import org.apache.catalina.Host;
import org.apache.catalina.Wrapper;
import org.apache.catalina.deploy.ApplicationParameter;
import org.apache.catalina.util.Enumerator;
import org.apache.catalina.util.ResourceSet;
import org.apache.catalina.util.ServerInfo;
import org.apache.catalina.util.StringManager;
import org.apache.naming.resources.DirContextURLStreamHandler;
import org.apache.naming.resources.Resource;
import org.apache.tomcat.util.buf.CharChunk;
import org.apache.tomcat.util.buf.MessageBytes;
import org.apache.tomcat.util.http.mapper.MappingData;
/**
* Standard implementation of <code>ServletContext that represents
* a web application's execution environment. An instance of this class is
* associated with each instance of <code>StandardContext.
*
* @author Craig R. McClanahan
* @author Remy Maucherat
* @version $Revision: 606606 $ $Date: 2007-12-23 21:09:23 +0100 (dim., 23 déc. 2007) $
*/
public class ApplicationContext
implements ServletContext {
// ----------------------------------------------------------- Constructors
/**
* Construct a new instance of this class, associated with the specified
* Context instance.
*
* @param context The associated Context instance
*/
public ApplicationContext(String basePath, StandardContext context) {
super();
this.context = context;
this.basePath = basePath;
}
// ----------------------------------------------------- Instance Variables
/**
* The context attributes for this context.
*/
protected Map attributes = new ConcurrentHashMap();
/**
* List of read only attributes for this context.
*/
private Map readOnlyAttributes = new ConcurrentHashMap();
/**
* The Context instance with which we are associated.
*/
private StandardContext context = null;
/**
* Empty collection to serve as the basis for empty enumerations.
* <strong>DO NOT ADD ANY ELEMENTS TO THIS COLLECTION!
*/
private static final ArrayList empty = new ArrayList();
/**
* The facade around this object.
*/
private ServletContext facade = new ApplicationContextFacade(this);
/**
* The merged context initialization parameters for this Context.
*/
private Map parameters = null;
/**
* The string manager for this package.
*/
private static final StringManager sm =
StringManager.getManager(Constants.Package);
/**
* Base path.
*/
private String basePath = null;
/**
* Thread local data used during request dispatch.
*/
private ThreadLocal<DispatchData> dispatchData =
new ThreadLocal<DispatchData>();
// --------------------------------------------------------- Public Methods
/**
* Return the resources object that is mapped to a specified path.
* The path must begin with a "/" and is interpreted as relative to the
* current context root.
*/
public DirContext getResources() {
return context.getResources();
}
// ------------------------------------------------- ServletContext Methods
/**
* Return the value of the specified context attribute, if any;
* otherwise return <code>null.
*
* @param name Name of the context attribute to return
*/
public Object getAttribute(String name) {
return (attributes.get(name));
}
/**
* Return an enumeration of the names of the context attributes
* associated with this context.
*/
public Enumeration getAttributeNames() {
return new Enumerator(attributes.keySet(), true);
}
/**
* Return a <code>ServletContext object that corresponds to a
* specified URI on the server. This method allows servlets to gain
* access to the context for various parts of the server, and as needed
* obtain <code>RequestDispatcher objects or resources from the
* context. The given path must be absolute (beginning with a "/"),
* and is interpreted based on our virtual host's document root.
*
* @param uri Absolute URI of a resource on the server
*/
public ServletContext getContext(String uri) {
// Validate the format of the specified argument
if ((uri == null) || (!uri.startsWith("/")))
return (null);
Context child = null;
try {
Host host = (Host) context.getParent();
String mapuri = uri;
while (true) {
child = (Context) host.findChild(mapuri);
if (child != null)
break;
int slash = mapuri.lastIndexOf('/');
if (slash < 0)
break;
mapuri = mapuri.substring(0, slash);
}
} catch (Throwable t) {
return (null);
}
if (child == null)
return (null);
if (context.getCrossContext()) {
// If crossContext is enabled, can always return the context
return child.getServletContext();
} else if (child == context) {
// Can still return the current context
return context.getServletContext();
} else {
// Nothing to return
return (null);
}
}
/**
* Return the main path associated with this context.
*/
public String getContextPath() {
return context.getPath();
}
/**
* Return the value of the specified initialization parameter, or
* <code>null if this parameter does not exist.
*
* @param name Name of the initialization parameter to retrieve
*/
public String getInitParameter(final String name) {
mergeParameters();
return ((String) parameters.get(name));
}
/**
* Return the names of the context's initialization parameters, or an
* empty enumeration if the context has no initialization parameters.
*/
public Enumeration getInitParameterNames() {
mergeParameters();
return (new Enumerator(parameters.keySet()));
}
/**
* Return the major version of the Java Servlet API that we implement.
*/
public int getMajorVersion() {
return (Constants.MAJOR_VERSION);
}
/**
* Return the minor version of the Java Servlet API that we implement.
*/
public int getMinorVersion() {
return (Constants.MINOR_VERSION);
}
/**
* Return the MIME type of the specified file, or <code>null if
* the MIME type cannot be determined.
*
* @param file Filename for which to identify a MIME type
*/
public String getMimeType(String file) {
if (file == null)
return (null);
int period = file.lastIndexOf(".");
if (period < 0)
return (null);
String extension = file.substring(period + 1);
if (extension.length() < 1)
return (null);
return (context.findMimeMapping(extension));
}
/**
* Return a <code>RequestDispatcher object that acts as a
* wrapper for the named servlet.
*
* @param name Name of the servlet for which a dispatcher is requested
*/
public RequestDispatcher getNamedDispatcher(String name) {
// Validate the name argument
if (name == null)
return (null);
// Create and return a corresponding request dispatcher
Wrapper wrapper = (Wrapper) context.findChild(name);
if (wrapper == null)
return (null);
return new ApplicationDispatcher(wrapper, null, null, null, null, name);
}
/**
* Return the real path for a given virtual path, if possible; otherwise
* return <code>null.
*
* @param path The path to the desired resource
*/
public String getRealPath(String path) {
if (!context.isFilesystemBased())
return null;
if (path == null) {
return null;
}
File file = new File(basePath, path);
return (file.getAbsolutePath());
}
/**
* Return a <code>RequestDispatcher instance that acts as a
* wrapper for the resource at the given path. The path must begin
* with a "/" and is interpreted as relative to the current context root.
*
* @param path The path to the desired resource.
*/
public RequestDispatcher getRequestDispatcher(String path) {
// Validate the path argument
if (path == null)
return (null);
if (!path.startsWith("/"))
throw new IllegalArgumentException
(sm.getString
("applicationContext.requestDispatcher.iae", path));
path = normalize(path);
if (path == null)
return (null);
// Use the thread local URI and mapping data
DispatchData dd = dispatchData.get();
if (dd == null) {
dd = new DispatchData();
dispatchData.set(dd);
}
MessageBytes uriMB = dd.uriMB;
uriMB.recycle();
// Get query string
String queryString = null;
int pos = path.indexOf('?');
if (pos >= 0) {
queryString = path.substring(pos + 1);
} else {
pos = path.length();
}
// Use the thread local mapping data
MappingData mappingData = dd.mappingData;
// Map the URI
CharChunk uriCC = uriMB.getCharChunk();
try {
uriCC.append(context.getPath(), 0, context.getPath().length());
/*
* Ignore any trailing path params (separated by ';') for mapping
* purposes
*/
int semicolon = path.indexOf(';');
if (pos >= 0 && semicolon > pos) {
semicolon = -1;
}
uriCC.append(path, 0, semicolon > 0 ? semicolon : pos);
context.getMapper().map(uriMB, mappingData);
if (mappingData.wrapper == null) {
return (null);
}
/*
* Append any trailing path params (separated by ';') that were
* ignored for mapping purposes, so that they're reflected in the
* RequestDispatcher's requestURI
*/
if (semicolon > 0) {
uriCC.append(path, semicolon, pos - semicolon);
}
} catch (Exception e) {
// Should never happen
log(sm.getString("applicationContext.mapping.error"), e);
return (null);
}
Wrapper wrapper = (Wrapper) mappingData.wrapper;
String wrapperPath = mappingData.wrapperPath.toString();
String pathInfo = mappingData.pathInfo.toString();
mappingData.recycle();
// Construct a RequestDispatcher to process this request
return new ApplicationDispatcher
(wrapper, uriCC.toString(), wrapperPath, pathInfo,
queryString, null);
}
/**
* Return the URL to the resource that is mapped to a specified path.
* The path must begin with a "/" and is interpreted as relative to the
* current context root.
*
* @param path The path to the desired resource
*
* @exception MalformedURLException if the path is not given
* in the correct form
*/
public URL getResource(String path)
throws MalformedURLException {
if (path == null || !path.startsWith("/")) {
throw new MalformedURLException(sm.getString("applicationContext.requestDispatcher.iae", path));
}
path = normalize(path);
if (path == null)
return (null);
String libPath = "/WEB-INF/lib/";
if ((path.startsWith(libPath)) && (path.endsWith(".jar"))) {
File jarFile = null;
if (context.isFilesystemBased()) {
jarFile = new File(basePath, path);
} else {
jarFile = new File(context.getWorkPath(), path);
}
if (jarFile.exists()) {
return jarFile.toURL();
} else {
return null;
}
} else {
DirContext resources = context.getResources();
if (resources != null) {
String fullPath = context.getName() + path;
String hostName = context.getParent().getName();
try {
resources.lookup(path);
return new URL
("jndi", "", 0, getJNDIUri(hostName, fullPath),
new DirContextURLStreamHandler(resources));
} catch (Exception e) {
// Ignore
}
}
}
return (null);
}
/**
* Return the requested resource as an <code>InputStream. The
* path must be specified according to the rules described under
* <code>getResource. If no such resource can be identified,
* return <code>null.
*
* @param path The path to the desired resource.
*/
public InputStream getResourceAsStream(String path) {
path = normalize(path);
if (path == null || !path.startsWith("/"))
return (null);
DirContext resources = context.getResources();
if (resources != null) {
try {
Object resource = resources.lookup(path);
if (resource instanceof Resource)
return (((Resource) resource).streamContent());
} catch (Exception e) {
}
}
return (null);
}
/**
* Return a Set containing the resource paths of resources member of the
* specified collection. Each path will be a String starting with
* a "/" character. The returned set is immutable.
*
* @param path Collection path
*/
public Set getResourcePaths(String path) {
// Validate the path argument
if (path == null) {
return null;
}
if (!path.startsWith("/")) {
throw new IllegalArgumentException
(sm.getString("applicationContext.resourcePaths.iae", path));
}
path = normalize(path);
if (path == null)
return (null);
DirContext resources = context.getResources();
if (resources != null) {
return (getResourcePathsInternal(resources, path));
}
return (null);
}
/**
* Internal implementation of getResourcesPath() logic.
*
* @param resources Directory context to search
* @param path Collection path
*/
private Set getResourcePathsInternal(DirContext resources, String path) {
ResourceSet set = new ResourceSet();
try {
listCollectionPaths(set, resources, path);
} catch (NamingException e) {
return (null);
}
set.setLocked(true);
return (set);
}
/**
* Return the name and version of the servlet container.
*/
public String getServerInfo() {
return (ServerInfo.getServerInfo());
}
/**
* @deprecated As of Java Servlet API 2.1, with no direct replacement.
*/
public Servlet getServlet(String name) {
return (null);
}
/**
* Return the display name of this web application.
*/
public String getServletContextName() {
return (context.getDisplayName());
}
/**
* @deprecated As of Java Servlet API 2.1, with no direct replacement.
*/
public Enumeration getServletNames() {
return (new Enumerator(empty));
}
/**
* @deprecated As of Java Servlet API 2.1, with no direct replacement.
*/
public Enumeration getServlets() {
return (new Enumerator(empty));
}
/**
* Writes the specified message to a servlet log file.
*
* @param message Message to be written
*/
public void log(String message) {
context.getLogger().info(message);
}
/**
* Writes the specified exception and message to a servlet log file.
*
* @param exception Exception to be reported
* @param message Message to be written
*
* @deprecated As of Java Servlet API 2.1, use
* <code>log(String, Throwable) instead
*/
public void log(Exception exception, String message) {
context.getLogger().error(message, exception);
}
/**
* Writes the specified message and exception to a servlet log file.
*
* @param message Message to be written
* @param throwable Exception to be reported
*/
public void log(String message, Throwable throwable) {
context.getLogger().error(message, throwable);
}
/**
* Remove the context attribute with the specified name, if any.
*
* @param name Name of the context attribute to be removed
*/
public void removeAttribute(String name) {
Object value = null;
boolean found = false;
// Remove the specified attribute
// Check for read only attribute
if (readOnlyAttributes.containsKey(name))
return;
found = attributes.containsKey(name);
if (found) {
value = attributes.get(name);
attributes.remove(name);
} else {
return;
}
// Notify interested application event listeners
Object listeners[] = context.getApplicationEventListeners();
if ((listeners == null) || (listeners.length == 0))
return;
ServletContextAttributeEvent event =
new ServletContextAttributeEvent(context.getServletContext(),
name, value);
for (int i = 0; i < listeners.length; i++) {
if (!(listeners[i] instanceof ServletContextAttributeListener))
continue;
ServletContextAttributeListener listener =
(ServletContextAttributeListener) listeners[i];
try {
context.fireContainerEvent("beforeContextAttributeRemoved",
listener);
listener.attributeRemoved(event);
context.fireContainerEvent("afterContextAttributeRemoved",
listener);
} catch (Throwable t) {
context.fireContainerEvent("afterContextAttributeRemoved",
listener);
// FIXME - should we do anything besides log these?
log(sm.getString("applicationContext.attributeEvent"), t);
}
}
}
/**
* Bind the specified value with the specified context attribute name,
* replacing any existing value for that name.
*
* @param name Attribute name to be bound
* @param value New attribute value to be bound
*/
public void setAttribute(String name, Object value) {
// Name cannot be null
if (name == null)
throw new IllegalArgumentException
(sm.getString("applicationContext.setAttribute.namenull"));
// Null value is the same as removeAttribute()
if (value == null) {
removeAttribute(name);
return;
}
Object oldValue = null;
boolean replaced = false;
// Add or replace the specified attribute
// Check for read only attribute
if (readOnlyAttributes.containsKey(name))
return;
oldValue = attributes.get(name);
if (oldValue != null)
replaced = true;
attributes.put(name, value);
// Notify interested application event listeners
Object listeners[] = context.getApplicationEventListeners();
if ((listeners == null) || (listeners.length == 0))
return;
ServletContextAttributeEvent event = null;
if (replaced)
event =
new ServletContextAttributeEvent(context.getServletContext(),
name, oldValue);
else
event =
new ServletContextAttributeEvent(context.getServletContext(),
name, value);
for (int i = 0; i < listeners.length; i++) {
if (!(listeners[i] instanceof ServletContextAttributeListener))
continue;
ServletContextAttributeListener listener =
(ServletContextAttributeListener) listeners[i];
try {
if (replaced) {
context.fireContainerEvent
("beforeContextAttributeReplaced", listener);
listener.attributeReplaced(event);
context.fireContainerEvent("afterContextAttributeReplaced",
listener);
} else {
context.fireContainerEvent("beforeContextAttributeAdded",
listener);
listener.attributeAdded(event);
context.fireContainerEvent("afterContextAttributeAdded",
listener);
}
} catch (Throwable t) {
if (replaced)
context.fireContainerEvent("afterContextAttributeReplaced",
listener);
else
context.fireContainerEvent("afterContextAttributeAdded",
listener);
// FIXME - should we do anything besides log these?
log(sm.getString("applicationContext.attributeEvent"), t);
}
}
}
// -------------------------------------------------------- Package Methods
protected StandardContext getContext() {
return this.context;
}
protected Map getReadonlyAttributes() {
return this.readOnlyAttributes;
}
/**
* Clear all application-created attributes.
*/
protected void clearAttributes() {
// Create list of attributes to be removed
ArrayList list = new ArrayList();
Iterator iter = attributes.keySet().iterator();
while (iter.hasNext()) {
list.add(iter.next());
}
// Remove application originated attributes
// (read only attributes will be left in place)
Iterator keys = list.iterator();
while (keys.hasNext()) {
String key = (String) keys.next();
removeAttribute(key);
}
}
/**
* Return the facade associated with this ApplicationContext.
*/
protected ServletContext getFacade() {
return (this.facade);
}
/**
* Set an attribute as read only.
*/
void setAttributeReadOnly(String name) {
if (attributes.containsKey(name))
readOnlyAttributes.put(name, name);
}
// -------------------------------------------------------- Private 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 instead.
*
* @param path Path to be normalized
*/
private String normalize(String path) {
if (path == null) {
return null;
}
String normalized = path;
// Normalize the slashes
if (normalized.indexOf('\\') >= 0)
normalized = normalized.replace('\\', '/');
// 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);
}
/**
* Merge the context initialization parameters specified in the application
* deployment descriptor with the application parameters described in the
* server configuration, respecting the <code>override property of
* the application parameters appropriately.
*/
private void mergeParameters() {
if (parameters != null)
return;
Map results = new ConcurrentHashMap();
String names[] = context.findParameters();
for (int i = 0; i < names.length; i++)
results.put(names[i], context.findParameter(names[i]));
ApplicationParameter params[] =
context.findApplicationParameters();
for (int i = 0; i < params.length; i++) {
if (params[i].getOverride()) {
if (results.get(params[i].getName()) == null)
results.put(params[i].getName(), params[i].getValue());
} else {
results.put(params[i].getName(), params[i].getValue());
}
}
parameters = results;
}
/**
* List resource paths (recursively), and store all of them in the given
* Set.
*/
private static void listCollectionPaths
(Set set, DirContext resources, String path)
throws NamingException {
Enumeration childPaths = resources.listBindings(path);
while (childPaths.hasMoreElements()) {
Binding binding = (Binding) childPaths.nextElement();
String name = binding.getName();
StringBuffer childPath = new StringBuffer(path);
if (!"/".equals(path) && !path.endsWith("/"))
childPath.append("/");
childPath.append(name);
Object object = binding.getObject();
if (object instanceof DirContext) {
childPath.append("/");
}
set.add(childPath.toString());
}
}
/**
* Get full path, based on the host name and the context path.
*/
private static String getJNDIUri(String hostName, String path) {
if (!path.startsWith("/"))
return "/" + hostName + "/" + path;
else
return "/" + hostName + path;
}
/**
* Internal class used as thread-local storage when doing path
* mapping during dispatch.
*/
private final class DispatchData {
public MessageBytes uriMB;
public MappingData mappingData;
public DispatchData() {
uriMB = MessageBytes.newInstance();
CharChunk uriCC = uriMB.getCharChunk();
uriCC.setLimit(-1);
mappingData = new MappingData();
}
}
}
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