vos/corelibs/vos/messagecontext.hh

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/*
    This file is part of the Virtual Object System of
    the Interreality project (http://interreality.org).

    Copyright (C) 2001-2003 Peter Amstutz

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA

    Peter Amstutz <tetron@interreality.org>
*/

#ifndef _MESSAGECONTEXT_HH_
#define _MESSAGECONTEXT_HH_

#include <vos/corelibs/vos/vosdefs.hh>
#include <vos/corelibs/vos/refcount.hh>

#include <stdexcept>
#include <map>

namespace VOS
{
    class Message;

/** A message substitution context. */
class VOS_API MessageContext : public virtual RefCounted
{
private:
    MessageContext* parentcontext;
    map<string, string> parameters;
    map<string, Message*> reply_record;
public:
    class NoSuchParameterError : public runtime_error {
    public:
        NoSuchParameterError(const string& s) : runtime_error(s) { };
    };

    MessageContext();
    ~MessageContext();

    void setParentContext(MessageContext* mc);

/** Get the parent (enclosing) context.
    @return the parent context, if any, or 0.  NOTE YOU MUST CALL release() WHEN DONE OR USE A pREF() BLOCK  */
    MessageContext* getParentContext();

    /** Do substitutions on a string based on this (and enclosing) contexts.
        @param s the string to substitute into (will be changed!)
        @param p offset to start processing (used internally)
    */
    void doSubstitution(string& s, unsigned int p=0);

    /** Set a substitution parameter.
        @param p the parameter name or key
        @param v the value to be substituted
     */
    void setParameter(const string& p, const string& v);

    /** Get a substitution parameter.
        @param p the parameter name or key
        @return the value to be substituted
        @throw NoSuchParameterError if there is no such parameter
     */
    string getParameter(const string& p) throw (NoSuchParameterError);

    /** The reply record is a record of our outgoing replies to method
        calls that we have received from others.  We collect these
        replies in the reply record for the purpose of doing
        substitutions using on the contents of these messages.
        @param m the message to add
     */
    void addToReplyRecord(Message* m);

    /** Tests to see if the reply record contains a message with a certain nonce.
        @param s the nonce
        @return whether a messages matches that nonce or not
    */
    bool replyRecordContains(const string& s);

    /** Retrieve a message from the reply record, given a nonce.
        @param s the nonce string
        @return the message nonce requested, or 0 if not found.
        NOTE YOU MUST CALL release() WHEN DONE OR USE A pREF() BLOCK
     */
    Message* getFromReplyRecord(const string& s);

    /** Remove a message from the reply record.
        @param m the message to be removed
     */
    void removeFromReplyRecord(Message* m);
};
}

#endif

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