##### Coverage Report - org.apache.turbine.pipeline.Valve

Classes in this File | Line Coverage | Branch Coverage | Complexity
Valve |
N/A | N/A
N/A | N/A
| 1.0;1

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     package org.apache.turbine.pipeline;
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     /*
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      * Licensed to the Apache Software Foundation (ASF) under one
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      * or more contributor license agreements.  See the NOTICE file
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      * distributed with this work for additional information
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      * regarding copyright ownership.  The ASF licenses this file
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      * to you under the Apache License, Version 2.0 (the
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      * "License"); you may not use this file except in compliance
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      * with the License.  You may obtain a copy of the License at
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      *
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      *   http://www.apache.org/licenses/LICENSE-2.0
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      *
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      * Unless required by applicable law or agreed to in writing,
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      * software distributed under the License is distributed on an
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      * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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      * KIND, either express or implied.  See the License for the
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      * specific language governing permissions and limitations
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      * under the License.
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      */
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     import java.io.IOException;
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     import org.apache.turbine.util.TurbineException;
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     /**
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      * <p>A <b>Valve</b> is a request processing component.  A series of
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      * Valves are generally associated with each other into a Pipeline.
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      * The detailed contract for a Valve is included in the description of
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      * the <code>invoke()</code> method below.</p>
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      *
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      * <b>HISTORICAL NOTE</b>:  The "Valve" name was assigned to this concept
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      * because a valve is what you use in a real world pipeline to control and/or
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      * modify flows through it.
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      *
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      * @author Craig R. McClanahan
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      * @author Gunnar Rjnning
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      * @author Peter Donald
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      * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
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      *
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      * @see #invoke(PipelineData, ValveContext)
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      */
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     public interface Valve
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     {
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         /**
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          * <p>Perform request processing as required by this Valve.</p>
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          *
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          * <p>An individual Valve <b>MAY</b> perform the following actions, in
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          * the specified order:</p>
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          * <ul>
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          * <li>Examine and/or modify the properties of the specified Request and
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          *     Response.
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          * <li>Examine the properties of the specified Request, completely generate
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          *     the corresponding Response, and return control to the caller.
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          * <li>Examine the properties of the specified Request and Response, wrap
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          *     either or both of these objects to supplement their functionality,
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          *     and pass them on.
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          * <li>If the corresponding Response was not generated (and control was not
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          *     returned, call the next Valve in the pipeline (if there is one) by
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          *     executing <code>context.invokeNext()</code>.
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          * <li>Examine, but not modify, the properties of the resulting Response
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          *     (which was created by a subsequently invoked Valve via a
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          *     call to <code>context.invokeNext()</code>).
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          * </ul>
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          *
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          * <p>A Valve <b>MUST NOT</b> do any of the following things:</p>
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          * <ul>
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          * <li>Change request properties that have already been used to direct
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          *     the flow of processing control for this request.
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          * <li>Create a completed Response <strong>AND</strong> pass this
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          *     Request and Response on to the next Valve in the pipeline.
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          * <li>Consume bytes from the input stream associated with the Request,
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          *     unless it is completely generating the response, or wrapping the
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          *     request before passing it on.
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          * <li>Modify the HTTP headers included with the Response after the
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          *     <code>invokeNext()</code> method has returned.
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          * <li>Perform any actions on the output stream associated with the
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          *     specified Response after the <code>invokeNext()</code> method has
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          *     returned.
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          * </ul>
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          *
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          * @param pipelineData The run-time information, including the servlet
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          * request and response we are processing.
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          * @param context The valve context used to invoke the next valve
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          *  in the current processing pipeline
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          *
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          * @exception IOException Thrown by a subsequent Valve.
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          * @exception TurbineException Thrown by a subsequent Valve.
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          */
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         public void invoke(PipelineData pipelineData, ValveContext context)
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             throws IOException, TurbineException;
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         /**
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          * Initialize the valve before using in a pipeline.
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          * @throws Exception if initialization fails
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          */
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         public void initialize()
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             throws Exception;
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     }