/*
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package com.sun.faces.el.impl;

import javax.servlet.ServletContext;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.jsp.PageContext;

import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * <p>This class is used to generate the implicit Map and List objects
 * that wrap various elements of the PageContext.  It also returns the
 * correct implicit object for a given implicit object name.
 *
 * @author Nathan Abramson - Art Technology Group
 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: rlubke $
 */

public class ImplicitObjects {

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

    static final String sAttributeName =
        "org.apache.taglibs.standard.ImplicitObjects";

    //-------------------------------------
    // Member variables
    //-------------------------------------

    PageContext mContext;
    Map mPage;
    Map mRequest;
    Map mSession;
    Map mApplication;
    Map mParam;
    Map mParams;
    Map mHeader;
    Map mHeaders;
    Map mInitParam;
    Map mCookie;

    //-------------------------------------
    /**
     * Constructor
     */
    public ImplicitObjects(PageContext pContext) {
        mContext = pContext;
    }

    //-------------------------------------
    /**
     * Finds the ImplicitObjects associated with the PageContext,
     * creating it if it doesn't yet exist.
     */
    public static ImplicitObjects getImplicitObjects(PageContext pContext) {
        ImplicitObjects objs =
            (ImplicitObjects)
            pContext.getAttribute(sAttributeName,
                                  PageContext.PAGE_SCOPE);
        if (objs == null) {
            objs = new ImplicitObjects(pContext);
            pContext.setAttribute(sAttributeName,
                                  objs,
                                  PageContext.PAGE_SCOPE);
        }
        return objs;
    }

    //-------------------------------------
    /**
     * Returns the Map that "wraps" page-scoped attributes
     */
    public Map getPageScopeMap() {
        if (mPage == null) {
            mPage = createPageScopeMap(mContext);
        }
        return mPage;
    }

    //-------------------------------------
    /**
     * Returns the Map that "wraps" request-scoped attributes
     */
    public Map getRequestScopeMap() {
        if (mRequest == null) {
            mRequest = createRequestScopeMap(mContext);
        }
        return mRequest;
    }

    //-------------------------------------
    /**
     * Returns the Map that "wraps" session-scoped attributes
     */
    public Map getSessionScopeMap() {
        if (mSession == null) {
            mSession = createSessionScopeMap(mContext);
        }
        return mSession;
    }

    //-------------------------------------
    /**
     * Returns the Map that "wraps" application-scoped attributes
     */
    public Map getApplicationScopeMap() {
        if (mApplication == null) {
            mApplication = createApplicationScopeMap(mContext);
        }
        return mApplication;
    }

    //-------------------------------------
    /**
     * Returns the Map that maps parameter name to a single parameter
     * values.
     */
    public Map getParamMap() {
        if (mParam == null) {
            mParam = createParamMap(mContext);
        }
        return mParam;
    }

    //-------------------------------------
    /**
     * Returns the Map that maps parameter name to an array of parameter
     * values.
     */
    public Map getParamsMap() {
        if (mParams == null) {
            mParams = createParamsMap(mContext);
        }
        return mParams;
    }

    //-------------------------------------
    /**
     * Returns the Map that maps header name to a single header
     * values.
     */
    public Map getHeaderMap() {
        if (mHeader == null) {
            mHeader = createHeaderMap(mContext);
        }
        return mHeader;
    }

    //-------------------------------------
    /**
     * Returns the Map that maps header name to an array of header
     * values.
     */
    public Map getHeadersMap() {
        if (mHeaders == null) {
            mHeaders = createHeadersMap(mContext);
        }
        return mHeaders;
    }

    //-------------------------------------
    /**
     * Returns the Map that maps init parameter name to a single init
     * parameter values.
     */
    public Map getInitParamMap() {
        if (mInitParam == null) {
            mInitParam = createInitParamMap(mContext);
        }
        return mInitParam;
    }

    //-------------------------------------
    /**
     * Returns the Map that maps cookie name to the first matching
     * Cookie in request.getCookies().
     */
    public Map getCookieMap() {
        if (mCookie == null) {
            mCookie = createCookieMap(mContext);
        }
        return mCookie;
    }

    //-------------------------------------
    // Methods for generating wrapper maps
    //-------------------------------------
    /**
     * Creates the Map that "wraps" page-scoped attributes
     */
    public static Map createPageScopeMap(PageContext pContext) {
        final PageContext context = pContext;
        return new EnumeratedMap() {
            public Enumeration enumerateKeys() {
                return context.getAttributeNamesInScope
                    (PageContext.PAGE_SCOPE);
            }


            public Object getValue(Object pKey) {
                if (pKey instanceof String) {
                    return context.getAttribute
                        ((String) pKey,
                         PageContext.PAGE_SCOPE);
                } else {
                    return null;
                }
            }


            public boolean isMutable() {
                return true;
            }
        };
    }

    //-------------------------------------
    /**
     * Creates the Map that "wraps" request-scoped attributes
     */
    public static Map createRequestScopeMap(PageContext pContext) {
        final PageContext context = pContext;
        return new EnumeratedMap() {
            public Enumeration enumerateKeys() {
                return context.getAttributeNamesInScope
                    (PageContext.REQUEST_SCOPE);
            }


            public Object getValue(Object pKey) {
                if (pKey instanceof String) {
                    return context.getAttribute
                        ((String) pKey,
                         PageContext.REQUEST_SCOPE);
                } else {
                    return null;
                }
            }


            public boolean isMutable() {
                return true;
            }
        };
    }

    //-------------------------------------
    /**
     * Creates the Map that "wraps" session-scoped attributes
     */
    public static Map createSessionScopeMap(PageContext pContext) {
        final PageContext context = pContext;
        return new EnumeratedMap() {
            public Enumeration enumerateKeys() {
                return context.getAttributeNamesInScope
                    (PageContext.SESSION_SCOPE);
            }


            public Object getValue(Object pKey) {
                if (pKey instanceof String) {
                    return context.getAttribute
                        ((String) pKey,
                         PageContext.SESSION_SCOPE);
                } else {
                    return null;
                }
            }


            public boolean isMutable() {
                return true;
            }
        };
    }

    //-------------------------------------
    /**
     * Creates the Map that "wraps" application-scoped attributes
     */
    public static Map createApplicationScopeMap(PageContext pContext) {
        final PageContext context = pContext;
        return new EnumeratedMap() {
            public Enumeration enumerateKeys() {
                return context.getAttributeNamesInScope
                    (PageContext.APPLICATION_SCOPE);
            }


            public Object getValue(Object pKey) {
                if (pKey instanceof String) {
                    return context.getAttribute
                        ((String) pKey,
                         PageContext.APPLICATION_SCOPE);
                } else {
                    return null;
                }
            }


            public boolean isMutable() {
                return true;
            }
        };
    }

    //-------------------------------------
    /**
     * Creates the Map that maps parameter name to single parameter
     * value.
     */
    public static Map createParamMap(PageContext pContext) {
        final HttpServletRequest request =
            (HttpServletRequest) pContext.getRequest();
        return new EnumeratedMap() {
            public Enumeration enumerateKeys() {
                return request.getParameterNames();
            }


            public Object getValue(Object pKey) {
                if (pKey instanceof String) {
                    return request.getParameter((String) pKey);
                } else {
                    return null;
                }
            }


            public boolean isMutable() {
                return false;
            }
        };
    }

    //-------------------------------------
    /**
     * Creates the Map that maps parameter name to an array of parameter
     * values.
     */
    public static Map createParamsMap(PageContext pContext) {
        final HttpServletRequest request =
            (HttpServletRequest) pContext.getRequest();
        return new EnumeratedMap() {
            public Enumeration enumerateKeys() {
                return request.getParameterNames();
            }


            public Object getValue(Object pKey) {
                if (pKey instanceof String) {
                    return request.getParameterValues((String) pKey);
                } else {
                    return null;
                }
            }


            public boolean isMutable() {
                return false;
            }
        };
    }

    //-------------------------------------
    /**
     * Creates the Map that maps header name to single header
     * value.
     */
    public static Map createHeaderMap(PageContext pContext) {
        final HttpServletRequest request =
            (HttpServletRequest) pContext.getRequest();
        return new EnumeratedMap() {
            public Enumeration enumerateKeys() {
                return request.getHeaderNames();
            }


            public Object getValue(Object pKey) {
                if (pKey instanceof String) {
                    return request.getHeader((String) pKey);
                } else {
                    return null;
                }
            }


            public boolean isMutable() {
                return false;
            }
        };
    }

    //-------------------------------------
    /**
     * Creates the Map that maps header name to an array of header
     * values.
     */
    public static Map createHeadersMap(PageContext pContext) {
        final HttpServletRequest request =
            (HttpServletRequest) pContext.getRequest();
        return new EnumeratedMap() {
            public Enumeration enumerateKeys() {
                return request.getHeaderNames();
            }


            public Object getValue(Object pKey) {
                if (pKey instanceof String) {
                    // Drain the header enumeration
                    List l = new ArrayList();
                    Enumeration e = request.getHeaders((String) pKey);
                    if (e != null) {
                        while (e.hasMoreElements()) {
                            l.add(e.nextElement());
                        }
                    }
                    String[] ret = (String[]) l.toArray(new String[l.size()]);
                    return ret;
                } else {
                    return null;
                }
            }


            public boolean isMutable() {
                return false;
            }
        };
    }

    //-------------------------------------
    /**
     * Creates the Map that maps init parameter name to single init
     * parameter value.
     */
    public static Map createInitParamMap(PageContext pContext) {
        final ServletContext context = pContext.getServletContext();
        return new EnumeratedMap() {
            public Enumeration enumerateKeys() {
                return context.getInitParameterNames();
            }


            public Object getValue(Object pKey) {
                if (pKey instanceof String) {
                    return context.getInitParameter((String) pKey);
                } else {
                    return null;
                }
            }


            public boolean isMutable() {
                return false;
            }
        };
    }

    //-------------------------------------
    /**
     * Creates the Map that maps cookie name to the first matching
     * Cookie in request.getCookies().
     */
    public static Map createCookieMap(PageContext pContext) {
        // Read all the cookies and construct the entire map
        HttpServletRequest request = (HttpServletRequest) pContext.getRequest();
        Cookie[] cookies = request.getCookies();
        Map ret = new HashMap();
        for (int i = 0; cookies != null && i < cookies.length; i++) {
            Cookie cookie = cookies[i];
            if (cookie != null) {
                String name = cookie.getName();
                if (!ret.containsKey(name)) {
                    ret.put(name, cookie);
                }
            }
        }
        return ret;
    }

    //-------------------------------------
}
