1 /**
2 * This file Copyright (c) 2013-2018 Magnolia International
3 * Ltd. (http://www.magnolia-cms.com). All rights reserved.
4 *
5 *
6 * This file is dual-licensed under both the Magnolia
7 * Network Agreement and the GNU General Public License.
8 * You may elect to use one or the other of these licenses.
9 *
10 * This file is distributed in the hope that it will be
11 * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
12 * implied warranty of MERCHANTABILITY or FITNESS FOR A
13 * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
14 * Redistribution, except as permitted by whichever of the GPL
15 * or MNA you select, is prohibited.
16 *
17 * 1. For the GPL license (GPL), you can redistribute and/or
18 * modify this file under the terms of the GNU General
19 * Public License, Version 3, as published by the Free Software
20 * Foundation. You should have received a copy of the GNU
21 * General Public License, Version 3 along with this program;
22 * if not, write to the Free Software Foundation, Inc., 51
23 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
24 *
25 * 2. For the Magnolia Network Agreement (MNA), this file
26 * and the accompanying materials are made available under the
27 * terms of the MNA which accompanies this distribution, and
28 * is available at http://www.magnolia-cms.com/mna.html
29 *
30 * Any modifications to this file must keep this entire header
31 * intact.
32 *
33 */
34 package info.magnolia.commands.chain;
35
36 import java.util.Collection;
37 import java.util.Collections;
38 import java.util.LinkedList;
39 import java.util.List;
40
41 import org.slf4j.Logger;
42 import org.slf4j.LoggerFactory;
43
44
45 /**
46 * Replacement for org.apache.commons.chain.impl.ChainBase. Base Chain
47 * implementation.
48 */
49 public class ChainBase implements Chain {
50
51 private final static Logger log = LoggerFactory.getLogger(ChainBase.class);
52
53 protected List<Command> commands = new LinkedList<Command>();
54
55 protected boolean frozen = false;
56
57 public ChainBase() {
58 }
59
60 public ChainBase(Command command) {
61 addCommand(command);
62 }
63
64 public ChainBase(Command... commands) {
65 for (Command command : commands) {
66 addCommand(command);
67 }
68 }
69
70 public ChainBase(Collection<Command> commands) {
71 this(commands.toArray(new Command[0]));
72 }
73
74 @Override
75 public void addCommand(Command command) {
76 if (command == null) {
77 throw new IllegalArgumentException();
78 }
79 if (frozen) {
80 throw new IllegalStateException();
81 }
82 commands.add(command);
83 }
84
85 @Override
86 public boolean execute(Context context) throws Exception {
87 // Verify our parameters
88 if (context == null) {
89 throw new IllegalArgumentException();
90 }
91 // Freeze the configuration of the command list
92 frozen = true;
93 // Execute the commands in this list until one returns true
94 // or throws an exception
95 boolean saveResult = false;
96 Exception saveException = null;
97 int i = 0;
98 int n = commands.size();
99 for (i = 0; i < n; i++) {
100 try {
101 saveResult = commands.get(i).execute(context);
102 if (saveResult) {
103 break;
104 }
105 } catch (Exception e) {
106 saveException = e;
107 break;
108 }
109 }
110 // Call postprocess methods on Filters in reverse order
111 if (i >= n) { // Fell off the end of the chain
112 i--;
113 }
114 boolean handled = false;
115 boolean result = false;
116 for (int j = i; j >= 0; j--) {
117 if (commands.get(j) instanceof Filter) {
118 try {
119 result = ((Filter) commands.get(j)).postprocess(context, saveException);
120 if (result) {
121 handled = true;
122 }
123 } catch (Exception e) {
124 // Silently ignore
125 }
126 }
127 }
128 // Return the exception or result state from the last execute()
129 if ((saveException != null) && !handled) {
130 throw saveException;
131 }
132 return (saveResult);
133 }
134
135 /**
136 * Returns <b>unmodifiable</b> list of commands.
137 */
138 public List<Command> getCommands() {
139 return Collections.unmodifiableList(commands);
140 }
141
142 @Override
143 public Command clone() throws CloneNotSupportedException {
144 ChainBaseChainBase.html#ChainBase">ChainBase copy = new ChainBase();
145 for (Command c : this.commands) {
146 copy.addCommand(c.clone());
147 }
148 return copy;
149 }
150
151 }