001: /*
002: * $Header: /home/cvs/jakarta-tomcat-4.0/catalina/src/share/org/apache/catalina/ValveContext.java,v 1.3 2001/07/22 20:13:30 pier Exp $
003: * $Revision: 1.3 $
004: * $Date: 2001/07/22 20:13:30 $
005: *
006: * ====================================================================
007: *
008: * The Apache Software License, Version 1.1
009: *
010: * Copyright (c) 1999-2001 The Apache Software Foundation. All rights
011: * reserved.
012: *
013: * Redistribution and use in source and binary forms, with or without
014: * modification, are permitted provided that the following conditions
015: * are met:
016: *
017: * 1. Redistributions of source code must retain the above copyright
018: * notice, this list of conditions and the following disclaimer.
019: *
020: * 2. Redistributions in binary form must reproduce the above copyright
021: * notice, this list of conditions and the following disclaimer in
022: * the documentation and/or other materials provided with the
023: * distribution.
024: *
025: * 3. The end-user documentation included with the redistribution, if
026: * any, must include the following acknowlegement:
027: * "This product includes software developed by the
028: * Apache Software Foundation (http://www.apache.org/)."
029: * Alternately, this acknowlegement may appear in the software itself,
030: * if and wherever such third-party acknowlegements normally appear.
031: *
032: * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
033: * Foundation" must not be used to endorse or promote products derived
034: * from this software without prior written permission. For written
035: * permission, please contact apache@apache.org.
036: *
037: * 5. Products derived from this software may not be called "Apache"
038: * nor may "Apache" appear in their names without prior written
039: * permission of the Apache Group.
040: *
041: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
042: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
043: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
044: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
045: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
046: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
047: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
048: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
049: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
050: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
051: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
052: * SUCH DAMAGE.
053: * ====================================================================
054: *
055: * This software consists of voluntary contributions made by many
056: * individuals on behalf of the Apache Software Foundation. For more
057: * information on the Apache Software Foundation, please see
058: * <http://www.apache.org/>.
059: *
060: * [Additional notices, if required by prior licensing conditions]
061: *
062: */
063:
064: package org.apache.catalina;
065:
066: import java.io.IOException;
067: import javax.servlet.ServletException;
068:
069: /**
070: * <p>A <b>ValveContext</b> is the mechanism by which a Valve can trigger the
071: * execution of the next Valve in a Pipeline, without having to know anything
072: * about the internal implementation mechanisms. An instance of a class
073: * implementing this interface is passed as a parameter to the
074: * <code>Valve.invoke()</code> method of each executed Valve.</p>
075: *
076: * <p><strong>IMPLEMENTATION NOTE</strong>: It is up to the implementation of
077: * ValveContext to ensure that simultaneous requests being processed (by
078: * separate threads) through the same Pipeline do not interfere with each
079: * other's flow of control.</p>
080: *
081: * @author Craig R. McClanahan
082: * @author Gunnar Rjnning
083: * @author Peter Donald
084: * @version $Revision: 1.3 $ $Date: 2001/07/22 20:13:30 $
085: */
086:
087: public interface ValveContext {
088:
089: //-------------------------------------------------------------- Properties
090:
091: /**
092: * Return descriptive information about this ValveContext implementation.
093: */
094: public String getInfo();
095:
096: //---------------------------------------------------------- Public Methods
097:
098: /**
099: * Cause the <code>invoke()</code> method of the next Valve that is part of
100: * the Pipeline currently being processed (if any) to be executed, passing
101: * on the specified request and response objects plus this
102: * <code>ValveContext</code> instance. Exceptions thrown by a subsequently
103: * executed Valve (or a Filter or Servlet at the application level) will be
104: * passed on to our caller.
105: *
106: * If there are no more Valves to be executed, an appropriate
107: * ServletException will be thrown by this ValveContext.
108: *
109: * @param request The request currently being processed
110: * @param response The response currently being created
111: *
112: * @exception IOException if thrown by a subsequent Valve, Filter, or
113: * Servlet
114: * @exception ServletException if thrown by a subsequent Valve, Filter,
115: * or Servlet
116: * @exception ServletException if there are no further Valves configured
117: * in the Pipeline currently being processed
118: */
119: public void invokeNext(Request request, Response response)
120: throws IOException, ServletException;
121:
122: }
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