1 //
2 // ========================================================================
3 // Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
4 // ------------------------------------------------------------------------
5 // All rights reserved. This program and the accompanying materials
6 // are made available under the terms of the Eclipse Public License v1.0
7 // and Apache License v2.0 which accompanies this distribution.
8 //
9 // The Eclipse Public License is available at
10 // http://www.eclipse.org/legal/epl-v10.html
11 //
12 // The Apache License v2.0 is available at
13 // http://www.opensource.org/licenses/apache2.0.php
14 //
15 // You may elect to redistribute this code under either of these licenses.
16 // ========================================================================
17 //
18
19 package org.eclipse.jetty.servlet;
20
21 import java.io.IOException;
22
23 import javax.servlet.ServletContext;
24 import javax.servlet.UnavailableException;
25
26 import org.eclipse.jetty.server.handler.ContextHandler;
27 import org.eclipse.jetty.util.Loader;
28 import org.eclipse.jetty.util.annotation.ManagedAttribute;
29 import org.eclipse.jetty.util.component.AbstractLifeCycle;
30 import org.eclipse.jetty.util.component.ContainerLifeCycle;
31 import org.eclipse.jetty.util.component.Dumpable;
32 import org.eclipse.jetty.util.log.Log;
33 import org.eclipse.jetty.util.log.Logger;
34
35 /**
36 * AbstractHolder
37 *
38 * Base class for all servlet-related classes that may be lazily instantiated (eg servlet, filter,
39 * listener), and/or require metadata to be held regarding their origin
40 * (web.xml, annotation, programmatic api etc).
41 * @param <T> the type of holder
42 */
43 public abstract class BaseHolder<T> extends AbstractLifeCycle implements Dumpable
44 {
45 private static final Logger LOG = Log.getLogger(BaseHolder.class);
46
47
48 public enum Source { EMBEDDED, JAVAX_API, DESCRIPTOR, ANNOTATION };
49
50 final protected Source _source;
51 protected transient Class<? extends T> _class;
52 protected String _className;
53 protected boolean _extInstance;
54 protected ServletHandler _servletHandler;
55
56 /* ---------------------------------------------------------------- */
57 protected BaseHolder(Source source)
58 {
59 _source=source;
60 }
61
62 /* ------------------------------------------------------------ */
63 public Source getSource()
64 {
65 return _source;
66 }
67
68 /* ------------------------------------------------------------ */
69 /**
70 * Do any setup necessary after starting
71 * @throws Exception if unable to initialize
72 */
73 public void initialize()
74 throws Exception
75 {
76 if (!isStarted())
77 throw new IllegalStateException("Not started: "+this);
78 }
79
80 /* ------------------------------------------------------------ */
81 @SuppressWarnings("unchecked")
82 @Override
83 public void doStart()
84 throws Exception
85 {
86 //if no class already loaded and no classname, make permanently unavailable
87 if (_class==null && (_className==null || _className.equals("")))
88 throw new UnavailableException("No class in holder");
89
90 //try to load class
91 if (_class==null)
92 {
93 try
94 {
95 _class=Loader.loadClass(Holder.class, _className);
96 if(LOG.isDebugEnabled())
97 LOG.debug("Holding {} from {}",_class,_class.getClassLoader());
98 }
99 catch (Exception e)
100 {
101 LOG.warn(e);
102 throw new UnavailableException(e.getMessage());
103 }
104 }
105 }
106
107
108 /* ------------------------------------------------------------ */
109 @Override
110 public void doStop()
111 throws Exception
112 {
113 if (!_extInstance)
114 _class=null;
115 }
116
117
118 /* ------------------------------------------------------------ */
119 @ManagedAttribute(value="Class Name", readonly=true)
120 public String getClassName()
121 {
122 return _className;
123 }
124
125 /* ------------------------------------------------------------ */
126 public Class<? extends T> getHeldClass()
127 {
128 return _class;
129 }
130
131 /* ------------------------------------------------------------ */
132 /**
133 * @return Returns the servletHandler.
134 */
135 public ServletHandler getServletHandler()
136 {
137 return _servletHandler;
138 }
139
140
141 /* ------------------------------------------------------------ */
142 /**
143 * @param servletHandler The {@link ServletHandler} that will handle requests dispatched to this servlet.
144 */
145 public void setServletHandler(ServletHandler servletHandler)
146 {
147 _servletHandler = servletHandler;
148 }
149
150 /* ------------------------------------------------------------ */
151 /**
152 * @param className The className to set.
153 */
154 public void setClassName(String className)
155 {
156 _className = className;
157 _class=null;
158 }
159
160 /* ------------------------------------------------------------ */
161 /**
162 * @param held The class to hold
163 */
164 public void setHeldClass(Class<? extends T> held)
165 {
166 _class=held;
167 if (held!=null)
168 {
169 _className=held.getName();
170 }
171 }
172
173
174 /* ------------------------------------------------------------ */
175 protected void illegalStateIfContextStarted()
176 {
177 if (_servletHandler!=null)
178 {
179 ServletContext context=_servletHandler.getServletContext();
180 if ((context instanceof ContextHandler.Context) && ((ContextHandler.Context)context).getContextHandler().isStarted())
181 throw new IllegalStateException("Started");
182 }
183 }
184
185 /* ------------------------------------------------------------ */
186 /**
187 * @return True if this holder was created for a specific instance.
188 */
189 public boolean isInstance()
190 {
191 return _extInstance;
192 }
193
194
195 /* ------------------------------------------------------------ */
196 @Override
197 public void dump(Appendable out, String indent) throws IOException
198 {
199 out.append(toString())
200 .append(" - ").append(AbstractLifeCycle.getState(this)).append("\n");
201 }
202
203 /* ------------------------------------------------------------ */
204 @Override
205 public String dump()
206 {
207 return ContainerLifeCycle.dump(this);
208 }
209 }