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1   /*
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3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
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7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
21   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22   * or visit www.oracle.com if you need additional information or have any
23   * questions.
24   */
25  
26  package com.sun.xml.internal.ws.api.server;
27  
28  import java.util.Collection;
29  import java.util.Collections;
30  import java.util.Set;
31  import java.util.concurrent.CopyOnWriteArraySet;
32  
33  import com.sun.istack.internal.NotNull;
34  import com.sun.xml.internal.ws.api.Component;
35  import com.sun.xml.internal.ws.api.ComponentEx;
36  import com.sun.xml.internal.ws.api.ComponentRegistry;
37  
38  /**
39   * Root of the SPI implemented by the container
40   * (such as application server.)
41   *
42   * <p>
43   * Often technologies that are built on top of JAX-WS
44   * (such as Tango) needs to negotiate private contracts between
45   * them and the container. This interface allows such technologies
46   * to query the negotiated SPI by using the {@link #getSPI(Class)}.
47   *
48   * <p>
49   * For example, if a security pipe needs to get some information
50   * from a container, they can do the following:
51   * <ol>
52   *  <li>Negotiate an interface with the container and define it.
53   *      (let's call it <tt>ContainerSecuritySPI</tt>.)
54   *  <li>The container will implement <tt>ContainerSecuritySPI</tt>.
55   *  <li>At the runtime, a security pipe gets
56   *      {@link WSEndpoint} and then to {@link Container}.
57   *  <li>It calls <tt>container.getSPI(ContainerSecuritySPI.class)</tt>
58   *  <li>The container returns an instance of <tt>ContainerSecuritySPI</tt>.
59   *  <li>The security pipe talks to the container through this SPI.
60   * </ol>
61   *
62   * <p>
63   * This protects JAX-WS from worrying about the details of such contracts,
64   * while still providing the necessary service of hooking up those parties.
65   *
66   * <p>
67   * Technologies that run inside JAX-WS server runtime can access this object through
68   * {@link WSEndpoint#getContainer()}. In the client runtime, it can be accessed from
69   * {@link ContainerResolver#getContainer()}
70   *
71   * @author Kohsuke Kawaguchi
72   * @see WSEndpoint
73   */
74  public abstract class Container implements ComponentRegistry, ComponentEx {
75          private final Set<Component> components = new CopyOnWriteArraySet<Component>();
76  
77      /**
78       * For derived classes.
79       */
80      protected Container() {
81      }
82  
83      /**
84       * Constant that represents a "no {@link Container}",
85       * which always returns null from {@link #getSPI(Class)}.
86       */
87      public static final Container NONE = new NoneContainer();
88  
89      private static final class NoneContainer extends Container {
90      }
91  
92      public <S> S getSPI(Class<S> spiType) {
93          if (components == null) return null;
94          for (Component c : components) {
95                  S s = c.getSPI(spiType);
96                  if (s != null)
97                          return s;
98          }
99          return null;
100     }
101 
102         public Set<Component> getComponents() {
103                 return components;
104         }
105 
106         public @NotNull <E> Iterable<E> getIterableSPI(Class<E> spiType) {
107         E item = getSPI(spiType);
108         if (item != null) {
109                 Collection<E> c = Collections.singletonList(item);
110                 return c;
111         }
112         return Collections.emptySet();
113     }
114 }