1 /****************************************************************
2 * Licensed to the Apache Software Foundation (ASF) under one *
3 * or more contributor license agreements. See the NOTICE file *
4 * distributed with this work for additional information *
5 * regarding copyright ownership. The ASF licenses this file *
6 * to you under the Apache License, Version 2.0 (the *
7 * "License"); you may not use this file except in compliance *
8 * with the License. You may obtain a copy of the License at *
9 * *
10 * http://www.apache.org/licenses/LICENSE-2.0 *
11 * *
12 * Unless required by applicable law or agreed to in writing, *
13 * software distributed under the License is distributed on an *
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY *
15 * KIND, either express or implied. See the License for the *
16 * specific language governing permissions and limitations *
17 * under the License. *
18 ****************************************************************/
19
20 package org.apache.jsieve.commands;
21
22 import org.apache.jsieve.Arguments;
23 import org.apache.jsieve.Block;
24 import org.apache.jsieve.ExecutableCommand;
25 import org.apache.jsieve.SieveContext;
26 import org.apache.jsieve.exception.CommandException;
27 import org.apache.jsieve.exception.SieveException;
28 import org.apache.jsieve.mail.MailAdapter;
29
30 /**
31 * Abstract class AbstractCommand defines a framework of common behavior for
32 * Sieve Commands.
33 */
34 public abstract class AbstractCommand implements ExecutableCommand {
35
36 /**
37 * Constructor for AbstractCommand.
38 */
39 public AbstractCommand() {
40 super();
41 }
42
43 /**
44 * Framework method validateState is invoked before a Sieve Command is
45 * executed to validate its state. Subclass methods are expected to override
46 * or extend this method to perform their own validation as appropriate.
47 *
48 * @param context
49 * <code>SieveContext</code> giving contextual information, not
50 * null
51 * @throws CommandException
52 */
53 protected void validateState(SieveContext context) throws CommandException {
54 }
55
56 /**
57 * Framework method updateState is invoked after a Sieve Command has
58 * executed to update the Sieve state. Subclass methods are expected to
59 * override or extend this method to update state as appropriate.
60 *
61 * @param context not null
62 */
63 protected void updateState(SieveContext context) {
64 }
65
66 /**
67 * Framework method validateArguments is invoked before a Sieve Command is
68 * executed to validate its arguments. Subclass methods are expected to
69 * override or extend this method to perform their own validation as
70 * appropriate.
71 *
72 * @param arguments
73 * @param context
74 * <code>SieveContext</code> giving contextual information, not
75 * null
76 * @throws SieveException
77 */
78 protected void validateArguments(Arguments arguments, SieveContext context)
79 throws SieveException {
80 if (!arguments.getArgumentList().isEmpty())
81 throw context.getCoordinate().syntaxException(
82 "Found unexpected arguments");
83 }
84
85 /**
86 * Framework method validateBlock is invoked before a Sieve Command is
87 * executed to validate its Block. Subclass methods are expected to override
88 * or extend this method to perform their own validation as appropriate.
89 *
90 * @param block
91 * @param context
92 * <code>ScriptCoordinate</code> giving positional information,
93 * not null
94 * @throws SieveException
95 */
96 protected void validateBlock(Block block, SieveContext context)
97 throws SieveException {
98 if (null != block)
99 throw context.getCoordinate().syntaxException(
100 "Found unexpected Block. Missing ';'?");
101 }
102
103 /**
104 * <p>
105 * Method execute executes a basic Sieve Command after first invoking
106 * framework methods to validate that Sieve is in a legal state to invoke
107 * the Command and that the Command arguments are legal. After invocation, a
108 * framework method is invoked to update the state.
109 * </p>
110 *
111 * <p>
112 * Also,
113 * </p>
114 *
115 * @see org.apache.jsieve.Executable#execute(MailAdapter, SieveContext)
116 */
117 public Object execute(MailAdapter mail, Arguments arguments, Block block,
118 SieveContext context) throws SieveException {
119 validateState(context);
120 validateArguments(arguments, context);
121 validateBlock(block, context);
122 Object result = executeBasic(mail, arguments, block, context);
123 updateState(context);
124 return result;
125 }
126
127 /**
128 * Abstract method executeBasic invokes a Sieve Command.
129 *
130 * @param mail
131 * @param arguments
132 * @param block
133 * @param context
134 * <code>SieveContext</code> giving contextual information, not
135 * null
136 * @return Object
137 * @throws SieveException
138 */
139 abstract protected Object executeBasic(MailAdapter mail,
140 Arguments arguments, Block block, SieveContext context)
141 throws SieveException;
142
143 }