/*
* 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 jakarta.servlet.jsp.el;
import java.util.AbstractMap;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import jakarta.el.ELContext;
import jakarta.el.ELResolver;
import jakarta.el.PropertyNotWritableException;
import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpSession;
import jakarta.servlet.jsp.JspContext;
import jakarta.servlet.jsp.PageContext;
/**
* Provides resolution in EL for the implicit variables of a JSP page.
*
* @since JSP 2.1
*/
public class ImplicitObjectELResolver extends ELResolver {
/**
* Creates an instance of the implicit object resolver for EL.
*/
public ImplicitObjectELResolver() {
super();
}
@Override
public Object getValue(ELContext context, Object base, Object property) {
Objects.requireNonNull(context);
if (base == null && property != null) {
Scope scope = Scope.lookupMap.get(property.toString());
if (scope != null) {
return scope.getScopeValue(context, null, property);
}
}
return null;
}
@Override
public Class<?> getType(ELContext context, Object base, Object property) {
Objects.requireNonNull(context);
if (base == null && property != null) {
if (Scope.lookupMap.containsKey(property.toString())) {
context.setPropertyResolved(null, property);
}
}
return null;
}
@Override
public void setValue(ELContext context, Object base, Object property, Object value) {
Objects.requireNonNull(context);
if (base == null && property != null) {
if (Scope.lookupMap.containsKey(property.toString())) {
context.setPropertyResolved(null, property);
throw new PropertyNotWritableException();
}
}
}
@Override
public boolean isReadOnly(ELContext context, Object base, Object property) {
Objects.requireNonNull(context);
if (base == null && property != null) {
if (Scope.lookupMap.containsKey(property.toString())) {
context.setPropertyResolved(null, property);
return true;
}
}
return false;
}
@Override
public Class<String> getCommonPropertyType(ELContext context, Object base) {
if (base == null) {
return String.class;
}
return null;
}
private static class ScopeManager {
private static final String MNGR_KEY = ScopeManager.class.getName();
private final PageContext page;
private Map<String,Object> applicationScope;
private Map<String,Cookie> cookie;
private Map<String,String> header;
private Map<String,String[]> headerValues;
private Map<String,String> initParam;
private Map<String,Object> pageScope;
private Map<String,String> param;
private Map<String,String[]> paramValues;
private Map<String,Object> requestScope;
private Map<String,Object> sessionScope;
ScopeManager(PageContext page) {
this.page = page;
}
public static ScopeManager get(PageContext page) {
ScopeManager mngr = (ScopeManager) page.getAttribute(MNGR_KEY);
if (mngr == null) {
mngr = new ScopeManager(page);
page.setAttribute(MNGR_KEY, mngr);
}
return mngr;
}
public Map<String,Object> getApplicationScope() {
if (this.applicationScope == null) {
this.applicationScope = new ScopeMap<>() {
@Override
protected void setAttribute(String name, Object value) {
page.getServletContext().setAttribute(name, value);
}
@Override
protected void removeAttribute(String name) {
page.getServletContext().removeAttribute(name);
}
@Override
protected Enumeration<String> getAttributeNames() {
return page.getServletContext().getAttributeNames();
}
@Override
protected Object getAttribute(String name) {
return page.getServletContext().getAttribute(name);
}
};
}
return this.applicationScope;
}
public Map<String,Cookie> getCookie() {
if (this.cookie == null) {
this.cookie = new ScopeMap<>() {
@Override
protected Enumeration<String> getAttributeNames() {
Cookie[] cookies = ((HttpServletRequest) page.getRequest()).getCookies();
if (cookies != null) {
List<String> list = new ArrayList<>(cookies.length);
for (Cookie cookie : cookies) {
list.add(cookie.getName());
}
return Collections.enumeration(list);
}
return null;
}
@Override
protected Cookie getAttribute(String name) {
Cookie[] cookies = ((HttpServletRequest) page.getRequest()).getCookies();
if (cookies != null) {
for (Cookie cookie : cookies) {
if (name.equals(cookie.getName())) {
return cookie;
}
}
}
return null;
}
};
}
return this.cookie;
}
public Map<String,String> getHeader() {
if (this.header == null) {
this.header = new ScopeMap<>() {
@Override
protected Enumeration<String> getAttributeNames() {
return ((HttpServletRequest) page.getRequest()).getHeaderNames();
}
@Override
protected String getAttribute(String name) {
return ((HttpServletRequest) page.getRequest()).getHeader(name);
}
};
}
return this.header;
}
public Map<String,String[]> getHeaderValues() {
if (this.headerValues == null) {
this.headerValues = new ScopeMap<>() {
@Override
protected Enumeration<String> getAttributeNames() {
return ((HttpServletRequest) page.getRequest()).getHeaderNames();
}
@Override
protected String[] getAttribute(String name) {
Enumeration<String> e = ((HttpServletRequest) page.getRequest()).getHeaders(name);
if (e != null) {
List<String> list = new ArrayList<>();
while (e.hasMoreElements()) {
list.add(e.nextElement());
}
return list.toArray(new String[0]);
}
return null;
}
};
}
return this.headerValues;
}
public Map<String,String> getInitParam() {
if (this.initParam == null) {
this.initParam = new ScopeMap<>() {
@Override
protected Enumeration<String> getAttributeNames() {
return page.getServletContext().getInitParameterNames();
}
@Override
protected String getAttribute(String name) {
return page.getServletContext().getInitParameter(name);
}
};
}
return this.initParam;
}
public PageContext getPageContext() {
return this.page;
}
public Map<String,Object> getPageScope() {
if (this.pageScope == null) {
this.pageScope = new ScopeMap<>() {
@Override
protected void setAttribute(String name, Object value) {
page.setAttribute(name, value);
}
@Override
protected void removeAttribute(String name) {
page.removeAttribute(name);
}
@Override
protected Enumeration<String> getAttributeNames() {
return page.getAttributeNamesInScope(PageContext.PAGE_SCOPE);
}
@Override
protected Object getAttribute(String name) {
return page.getAttribute(name);
}
};
}
return this.pageScope;
}
public Map<String,String> getParam() {
if (this.param == null) {
this.param = new ScopeMap<>() {
@Override
protected Enumeration<String> getAttributeNames() {
return page.getRequest().getParameterNames();
}
@Override
protected String getAttribute(String name) {
return page.getRequest().getParameter(name);
}
};
}
return this.param;
}
public Map<String,String[]> getParamValues() {
if (this.paramValues == null) {
this.paramValues = new ScopeMap<>() {
@Override
protected String[] getAttribute(String name) {
return page.getRequest().getParameterValues(name);
}
@Override
protected Enumeration<String> getAttributeNames() {
return page.getRequest().getParameterNames();
}
};
}
return this.paramValues;
}
public Map<String,Object> getRequestScope() {
if (this.requestScope == null) {
this.requestScope = new ScopeMap<>() {
@Override
protected void setAttribute(String name, Object value) {
page.getRequest().setAttribute(name, value);
}
@Override
protected void removeAttribute(String name) {
page.getRequest().removeAttribute(name);
}
@Override
protected Enumeration<String> getAttributeNames() {
return page.getRequest().getAttributeNames();
}
@Override
protected Object getAttribute(String name) {
return page.getRequest().getAttribute(name);
}
};
}
return this.requestScope;
}
public Map<String,Object> getSessionScope() {
if (this.sessionScope == null) {
this.sessionScope = new ScopeMap<>() {
@Override
protected void setAttribute(String name, Object value) {
((HttpServletRequest) page.getRequest()).getSession().setAttribute(name, value);
}
@Override
protected void removeAttribute(String name) {
HttpSession session = page.getSession();
if (session != null) {
session.removeAttribute(name);
}
}
@Override
protected Enumeration<String> getAttributeNames() {
HttpSession session = page.getSession();
if (session != null) {
return session.getAttributeNames();
}
return null;
}
@Override
protected Object getAttribute(String name) {
HttpSession session = page.getSession();
if (session != null) {
return session.getAttribute(name);
}
return null;
}
};
}
return this.sessionScope;
}
}
private abstract static class ScopeMap<V> extends AbstractMap<String,V> {
protected abstract Enumeration<String> getAttributeNames();
protected abstract V getAttribute(String name);
@SuppressWarnings("unused")
protected void removeAttribute(String name) {
throw new UnsupportedOperationException();
}
@SuppressWarnings("unused")
protected void setAttribute(String name, Object value) {
throw new UnsupportedOperationException();
}
@Override
public final Set<Map.Entry<String,V>> entrySet() {
Enumeration<String> e = getAttributeNames();
Set<Map.Entry<String,V>> set = new HashSet<>();
if (e != null) {
while (e.hasMoreElements()) {
set.add(new ScopeEntry(e.nextElement()));
}
}
return set;
}
@Override
public final int size() {
int size = 0;
Enumeration<String> e = getAttributeNames();
if (e != null) {
while (e.hasMoreElements()) {
e.nextElement();
size++;
}
}
return size;
}
@Override
public final boolean containsKey(Object key) {
if (key == null) {
return false;
}
Enumeration<String> e = getAttributeNames();
if (e != null) {
while (e.hasMoreElements()) {
if (key.equals(e.nextElement())) {
return true;
}
}
}
return false;
}
private class ScopeEntry implements Map.Entry<String,V> {
private final String key;
ScopeEntry(String key) {
this.key = key;
}
@Override
public String getKey() {
return this.key;
}
@Override
public V getValue() {
return getAttribute(this.key);
}
@Override
public V setValue(Object value) {
if (value == null) {
removeAttribute(this.key);
} else {
setAttribute(this.key, value);
}
return null;
}
@Override
public boolean equals(Object obj) {
return obj != null && this.hashCode() == obj.hashCode();
}
@Override
public int hashCode() {
return this.key.hashCode();
}
}
@Override
public final V get(Object key) {
if (key != null) {
return getAttribute((String) key);
}
return null;
}
@Override
public final V put(String key, V value) {
Objects.requireNonNull(key);
if (value == null) {
this.removeAttribute(key);
} else {
this.setAttribute(key, value);
}
return null;
}
@Override
public final V remove(Object key) {
Objects.requireNonNull(key);
this.removeAttribute((String) key);
return null;
}
}
private enum Scope {
APPLICATION_SCOPE("applicationScope") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getApplicationScope();
}
},
COOKIE("cookie") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getCookie();
}
},
HEADER("header") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getHeader();
}
},
HEADER_VALUES("headerValues") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getHeaderValues();
}
},
INIT_PARAM("initParam") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getInitParam();
}
},
PAGE_CONTEXT("pageContext") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getPageContext();
}
},
PAGE_SCOPE("pageScope") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getPageScope();
}
},
PARAM("param") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getParam();
}
},
PARAM_VALUES("paramValues") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getParamValues();
}
},
REQUEST_SCOPE("requestScope") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getRequestScope();
}
},
SESSION_SCOPE("sessionScope") {
@Override
Object getScopeValue(ELContext context, Object base, Object property) {
return getScopeManager(context, base, property).getSessionScope();
}
};
private static final Map<String,Scope> lookupMap = new HashMap<>();
static {
for (Scope scope : values()) {
lookupMap.put(scope.implicitName, scope);
}
}
private static ScopeManager getScopeManager(ELContext context, Object base, Object property) {
PageContext page = (PageContext) context.getContext(JspContext.class);
context.setPropertyResolved(base, property);
return ScopeManager.get(page);
}
private final String implicitName;
Scope(String implicitName) {
this.implicitName = implicitName;
}
abstract Object getScopeValue(ELContext context, Object base, Object property);
}
}