Source code: org/apache/axis/Handler.java
1 /*
2 * Copyright 2001-2004 The Apache Software Foundation.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.apache.axis ;
18
19 import org.w3c.dom.Document;
20 import org.w3c.dom.Element;
21
22 import javax.xml.namespace.QName;
23 import java.io.Serializable;
24 import java.util.Hashtable;
25 import java.util.List;
26
27 /**
28 * An AXIS handler.
29 *
30 * @author Doug Davis (dug@us.ibm.com)
31 */
32 public interface Handler extends Serializable {
33 /**
34 * Init is called when the chain containing this Handler object
35 * is instantiated.
36 */
37 public void init();
38
39 /**
40 * Cleanup is called when the chain containing this Handler object
41 * is done processing the chain.
42 */
43 public void cleanup();
44
45 /**
46 * Invoke is called to do the actual work of the Handler object.
47 * If there is a fault during the processing of this method it is
48 * invoke's job to catch the exception and undo any partial work
49 * that has been completed. Once we leave 'invoke' if a fault
50 * is thrown, this classes 'onFault' method will be called.
51 * Invoke should rethrow any exceptions it catches, wrapped in
52 * an AxisFault.
53 *
54 * @param msgContext the <code>MessageContext</code> to process with this
55 * <code>Handler</code>.
56 * @throws AxisFault if the handler encounters an error
57 */
58 public void invoke(MessageContext msgContext) throws AxisFault ;
59
60 /**
61 * Called when a subsequent handler throws a fault.
62 *
63 * @param msgContext the <code>MessageContext</code> to process the fault
64 * to
65 */
66 public void onFault(MessageContext msgContext);
67
68 /**
69 * Indicate if this handler can process <code>qname</code>.
70 *
71 * @param qname the <code>QName</code> to check
72 * @return true if this <code>Handler</code> can handle <code>qname<code>,
73 * false otherwise
74 */
75 public boolean canHandleBlock(QName qname);
76
77 // fixme: will modifications to this List be reflected in the state of this
78 // handler?
79 /**
80 * Return a list of QNames which this Handler understands. By returning
81 * a particular QName here, we are committing to fulfilling any contracts
82 * defined in the specification of the SOAP header with that QName.
83 *
84 * @return a List of <code>QName</code> instances
85 */
86 public List getUnderstoodHeaders();
87
88 // fixme: doesn't specify what happens when an option is re-defined
89 /**
90 * Add the given option (name/value) to this handler's bag of options.
91 *
92 * @param name the name of the option
93 * @param value the new value of the option
94 */
95 public void setOption(String name, Object value);
96
97 /**
98 * Returns the option corresponding to the 'name' given.
99 *
100 * @param name the name of the option
101 * @return the value of the option
102 */
103 public Object getOption(String name);
104
105 /**
106 * Set the name (i.e. registry key) of this Handler.
107 *
108 * @param name the new name
109 */
110 public void setName(String name);
111
112 /**
113 * Return the name (i.e. registry key) for this <code>Handler</code>.
114 *
115 * @return the name for this <code>Handler</code>
116 */
117 public String getName();
118
119 // fixme: doesn't tell us if modifying this Hashset will modify this Handler
120 // fixme: do we mean to use a Hahset, or will Map do?
121 /**
122 * Return the entire list of options.
123 *
124 * @return a <code>Hashset</code> containing all name/value pairs
125 */
126 public Hashtable getOptions();
127
128 // fixme: this doesn't indicate if opts becomes the new value of
129 // getOptions(), or if it is merged into it. Also doesn't specify if
130 // modifications to opts after calling this method will affect this handler
131 /**
132 * Sets a whole list of options.
133 *
134 * @param opts a <code>Hashtable</code> of name-value pairs to use
135 */
136 public void setOptions(Hashtable opts);
137
138 // fixme: presumably doc is used as the factory & host for Element, and
139 // Element should not be grafted into doc by getDeploymentData, but will
140 // potentially be grafted in by code calling this - could we clarify this?
141 /**
142 * This will return the root element of an XML doc that describes the
143 * deployment information about this handler. This is NOT the WSDL,
144 * this is all of the static internal data use by Axis - WSDL takes into
145 * account run-time information (like which service we're talking about)
146 * this is just the data that's stored in the registry. Used by the
147 * 'list' Admin function.
148 *
149 * @param doc a <code>Document</code> within which to build the deployment
150 * data
151 * @return an Element representing the deployment data
152 */
153 public Element getDeploymentData(Document doc);
154
155 /**
156 * Obtain WSDL information. Some Handlers will implement this by
157 * merely setting properties in the MessageContext, others (providers)
158 * will take responsibility for doing the "real work" of generating
159 * WSDL for a given service.
160 *
161 * @param msgContext the <code>MessageContext</code> to generate the WSDL
162 * to
163 * @throws AxisFault if there was a problem generating the WSDL
164 */
165 public void generateWSDL(MessageContext msgContext) throws AxisFault;
166 };