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Java > Open Source Codes > org > archive > crawler > settings > MapType


1 /* MapType
2  *
3  * $Id: MapType.java,v 1.7.4.1 2007/01/13 01:31:27 stack-sf Exp $
4  *
5  * Created on Jan 8, 2004
6  *
7  * Copyright (C) 2004 Internet Archive.
8  *
9  * This file is part of the Heritrix web crawler (crawler.archive.org).
10  *
11  * Heritrix is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU Lesser Public License as published by
13  * the Free Software Foundation; either version 2.1 of the License, or
14  * any later version.
15  *
16  * Heritrix is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19  * GNU Lesser Public License for more details.
20  *
21  * You should have received a copy of the GNU Lesser Public License
22  * along with Heritrix; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24  */
25 package org.archive.crawler.settings;
26
27 import java.util.Iterator JavaDoc;
28 import java.util.List JavaDoc;
29
30 import javax.management.AttributeNotFoundException JavaDoc;
31 import javax.management.InvalidAttributeValueException JavaDoc;
32
33 import org.archive.crawler.settings.Constraint.FailedCheck;
34
35 /** This class represents a container of settings.
36  *
37  * This class is usually used to make it possible to have a dynamic number
38  * of ModuleTypes like for instance a list of filters of different type.
39  *
40  * When this type is overridden on a per domain basis, the following
41  * restrictions apply:
42  * <ul>
43  * <li>Added elements is placed after the elements in the map it overrides.
44  * <li>You can not remove elements from the map it overrides. If it is
45  * necessary to be able to remove an element, this has to be done by
46  * adding some disable feature to the modules referenced by the map. An
47  * example of this is the enabled attribute on the
48  * {@link org.archive.crawler.framework.Filter} class.
49  * <li>All elements defined in maps that this map overrides might have their
50  * settings changed, but the order can not be changed.
51  * </ul>
52  *
53  * @author John Erik Halse
54  */
55 public class MapType extends ComplexType {
56
57     private static final long serialVersionUID = -3694800285930202700L;
58
59     /** The content type allowed for this map. */
60     private final Type definition;
61
62     /** Construct a new MapType object.
63      *
64      * @param name the name of this element.
65      * @param description the description of the attribute.
66      */
67     public MapType(String JavaDoc name, String JavaDoc description) {
68         this(name, description, Object JavaDoc.class);
69     }
70
71     /** Construct a new MapType object.
72      *
73      * @param name the name of this element.
74      * @param description the description of the attribute.
75      * @param type the type allowed for this map
76      */
77     public MapType(String JavaDoc name, String JavaDoc description, Class JavaDoc type) {
78         super(name, description);
79         this.definition = new SimpleType("dummy", "dummy", null);
80         this.definition.setLegalValueType(type);
81     }
82
83     /** Add a new element to this map.
84      *
85      * @param settings the settings object for this method to have effect.
86      * @param element the element to be added.
87      * @return Element added.
88      * @throws InvalidAttributeValueException
89      */
90     public Type addElement(CrawlerSettings settings, Type element)
91         throws InvalidAttributeValueException JavaDoc {
92         settings = settings == null ? globalSettings() : settings;
93
94         if (settings != globalSettings()) {
95             try {
96                 getAttribute(settings, element.getName());
97                 // Element exist, throw an exception
98 throw new IllegalArgumentException JavaDoc(
99                     "Duplicate element: " + element.getName());
100
101             } catch (AttributeNotFoundException JavaDoc e) {
102                 // Element doesn't exist, ok to add
103 }
104         }
105
106         if (!(element instanceof MapType)) {
107             return super.addElement(settings, element);
108         } else {
109             throw new IllegalArgumentException JavaDoc("Nested maps are not allowed.");
110         }
111     }
112
113     /** Remove an attribute from the map.
114      *
115      * @param settings the settings object for which this method has effect.
116      * @param name name of the attribute to remove.
117      * @return the element that was removed.
118      * @throws AttributeNotFoundException is thrown if there is no attribute
119      * with the submitted name.
120      */
121     public Object JavaDoc removeElement(CrawlerSettings settings, String JavaDoc name)
122       throws AttributeNotFoundException JavaDoc {
123         settings = settings == null ? globalSettings() : settings;
124         return settings.getData(this).removeElement(name);
125     }
126
127     /** Move an attribute up one place in the list.
128      *
129      * @param settings the settings object for which this method has effect.
130      * @param name name of attribute to move.
131      * @return true if attribute was moved, false if attribute was already
132      * at the top.
133      * @throws AttributeNotFoundException is thrown if there is no attribute
134      * with the submitted name.
135      */
136     public boolean moveElementUp(CrawlerSettings settings, String JavaDoc name)
137       throws AttributeNotFoundException JavaDoc {
138         settings = settings == null ? globalSettings() : settings;
139         return settings.getData(this).moveElementUp(name);
140     }
141
142     /** Move an attribute down one place in the list.
143      *
144      * @param settings the settings object for which this method has effect.
145      * @param name name of attribute to move.
146      * @return true if attribute was moved, false if attribute was already
147      * at bottom.
148      * @throws AttributeNotFoundException is thrown if there is no attribute
149      * with the submitted name.
150      */
151     public boolean moveElementDown(CrawlerSettings settings, String JavaDoc name)
152       throws AttributeNotFoundException JavaDoc {
153         settings = settings == null ? globalSettings() : settings;
154         return settings.getData(this).moveElementDown(name);
155     }
156
157     /** Returns true if this map is empty.
158      *
159      * @param context the settings object for which this set of elements
160      * are valid.
161      * @return true if this map is empty.
162      */
163     public boolean isEmpty(Object JavaDoc context) {
164         Context ctxt = getSettingsFromObject(context);
165
166         DataContainer data = getDataContainerRecursive(ctxt);
167         while (data != null) {
168             if (data.hasAttributes()) {
169                 return false;
170             }
171             ctxt.settings = data.getSettings().getParent();
172             data = getDataContainerRecursive(ctxt);
173         }
174         return true;
175     }
176
177     /** Get the number of elements in this map.
178      *
179      * @param context the settings object for which this set of elements
180      * are valid.
181      * @return the number of elements in this map.
182      */
183     public int size(Object JavaDoc context) {
184         Context ctxt = getSettingsFromObject(context);
185
186         int size = 0;
187         DataContainer data = getDataContainerRecursive(ctxt);
188         while (data != null) {
189             size += data.size();
190             ctxt.settings = data.getSettings().getParent();
191             data = getDataContainerRecursive(ctxt);
192         }
193         return size;
194     }
195
196     /**
197      * Get the content type definition for attributes of this map.
198      *
199      * @param attributeName since all attributes of a map are of the same type,
200      * this value is not used.
201      * @return the content type definition for attributes of this map.
202      */
203     Type getDefinition(String JavaDoc attributeName) {
204         return definition;
205     }
206
207     /**
208      * Get the content type allowed for this map.
209      *
210      * @return the content type allowed for this map.
211      */
212     public Class JavaDoc getContentType() {
213         return this.definition.getLegalValueType();
214     }
215
216     FailedCheck checkValue(CrawlerSettings settings, String JavaDoc attributeName,
217             Type definition, Object JavaDoc value) {
218         FailedCheck res = super.checkValue(settings, attributeName, definition,
219                 value);
220
221         definition = super.getDefinition(attributeName);
222
223         // Check if value fulfills any constraints
224 List JavaDoc constraints = definition != null ? definition.getConstraints()
225                 : null;
226         if (constraints != null) {
227             FailedCheck ac = null;
228             for (Iterator JavaDoc it = constraints.iterator(); it.hasNext()
229                     && ac == null;) {
230                 ac = ((Constraint) it.next()).check(settings, this, definition,
231                         value);
232                 if (res == null
233                         || ac.getLevel().intValue() >= res.getLevel()
234                                 .intValue()) {
235                     res = ac;
236                 }
237             }
238         }
239
240         return res;
241     }
242
243     /* (non-Javadoc)
244      * @see org.archive.crawler.settings.Type#addConstraint(org.archive.crawler.settings.Constraint)
245      */
246     public void addConstraint(Constraint constraint) {
247         definition.addConstraint(constraint);
248     }
249
250     /* (non-Javadoc)
251      * @see org.archive.crawler.settings.Type#getConstraints()
252      */
253     public List JavaDoc getConstraints() {
254         return definition.getConstraints();
255     }
256 }
257
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