Clover Coverage Report - perfectjpattern(Aggregated)
Coverage timestamp: Sat Feb 28 2009 14:35:07 CET
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1    //----------------------------------------------------------------------
2    //
3    // PerfectJPattern: "Design patterns are good but components are better!"
4    // IHandler.java Copyright (c) 2009 Giovanni Azua Garcia
5    // bravegag@hotmail.com
6    //
7    // This program is free software; you can redistribute it and/or
8    // modify it under the terms of the GNU General Public License
9    // as published by the Free Software Foundation; either version 3
10    // of the License, or (at your option) any later version.
11    //
12    // This program is distributed in the hope that it will be useful,
13    // but WITHOUT ANY WARRANTY; without even the implied warranty of
14    // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15    // GNU General Public License for more details.
16    //
17    // You should have received a copy of the GNU General Public License
18    // along with this program; if not, see <http://www.gnu.org/licenses/>.
19    //
20    //----------------------------------------------------------------------
21    package org.perfectjpattern.core.api.behavioral.chainofresponsibility;
22   
23    /**
24    * <b>Chain of Responsibility Design Pattern</b>: Avoid coupling the sender of
25    * a request to its receiver by giving more than one object a chance to handle
26    * the request. Chain the receiving objects and pass the request along the chain
27    * until an object handles it. (Gamma et al, Design Patterns)<br/>
28    * <br/>
29    *
30    * <b>Responsibility</b>: Abstract definition of the "Handler".
31    *
32    * <ul>
33    * <li>Defines an interface for handling requests.</li>
34    * <li>Implements the Successor link.</li>
35    * </ul>
36    *
37    * <br/>
38    * Example usage:
39    * <pre><code>
40    * //
41    * // Create chain elements
42    * //
43    * IHandler myFirst = new ConcreteHandler();
44    * IHandler mySecond = new ConcreteHandler();
45    * IHandler myThird = new ConcreteHandler();
46    *
47    * //
48    * // Associate Handler elements
49    * //
50    * myFirst.setSuccessor(mySecond);
51    * mySecond.setSuccessor(myThird);
52    *
53    * //
54    * // Execute the first Handler that triggers the execution of the
55    * // complete chain.
56    * //
57    * myFirst.start(NullRequest.getInstance());
58    * </code></pre>
59    *
60    * @param <R> Request parameter type
61    *
62    * @author <a href="mailto:bravegag@hotmail.com">Giovanni Azua</a>
63    * @version $Revision: 1.0 $ $Date: Jun 23, 2007 1:27:25 PM $
64    */
65    public
 
66    interface IHandler<R>
67    {
68    //------------------------------------------------------------------------
69    // public
70    //------------------------------------------------------------------------
71    /**
72    * Returns true if this <code>IHandler</code> can handle the given request,
73    * false otherwise.
74    *
75    * @param aRequest Context-specific request to handle.
76    * @return true if this <code>IHandler</code> can handle the given request,
77    * false otherwise.
78    * @throws IllegalArgumentException 'aRequest' must not be null.
79    */
80    public boolean
81    canHandle(R aRequest)
82    throws IllegalArgumentException;
83   
84    //------------------------------------------------------------------------
85    /**
86    * Triggers execution of the Chain if the target Handler is the first
87    * reference, otherwise implements the decision-making regarding forwarding
88    * the request to its successor <code>IHandler</code> instance.
89    *
90    * @param aRequest Context-specific request to handle.
91    * @throws IllegalArgumentException 'aRequest' must not be null.
92    */
93    public void
94    start(R aRequest)
95    throws IllegalArgumentException;
96   
97    //------------------------------------------------------------------------
98    /**
99    * Handle the given request. Implements the actual handling logic and must
100    * not contain any decision-making regarding e.g. forwarding the request.
101    *
102    * @param aRequest Context-specific request to handle.
103    * @throws IllegalArgumentException 'aRequest' must not be null.
104    * @throws IllegalArgumentException 'aRequest' can not be handled.
105    */
106    public void
107    handle(R aRequest)
108    throws IllegalArgumentException;
109   
110    //------------------------------------------------------------------------
111    /**
112    * Returns the Successor handler.
113    *
114    * @return Successor handler.
115    */
116    public IHandler<R>
117    getSuccessor();
118   
119    //------------------------------------------------------------------------
120    /**
121    * Sets the Successor element.
122    *
123    * @param aSuccessor Successor handler
124    * @throws IllegalArgumentException 'aSuccessor' must not be null.
125    */
126    public void
127    setSuccessor(IHandler<R> aSuccessor)
128    throws IllegalArgumentException;
129   
130    //------------------------------------------------------------------------
131    /**
132    * Set the <code>IChainStrategy</code> to this <code>IHandler</code>.
133    * <code>IChainStrategy</code> allows to easily modify how the
134    * Chain should behave. Possible implementations are e.g.
135    * <ul>
136    * <li>Halt as soon as the first Handler processes the request</li>
137    * <li>Let all handlers process the request</li>
138    * <li>Let the first N handlers process the request</li>
139    * </ul>
140    *
141    * @param aStrategy Continuation strategy defines how the chain should
142    * behave
143    * @throws IllegalArgumentException 'aStrategy' must not be null.
144    */
145    public void
146    setChainStrategy(IChainStrategy aStrategy)
147    throws IllegalArgumentException;
148    }
 
CloverReport generated by Clover Code Coverage v2.4.2
Sat Feb 28 2009 14:35:10 CET.		   Clover: Open Source License registered to perfectjpattern.