001: /*
002: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
003: *
004: * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
005: *
006: * The contents of this file are subject to the terms of either the GNU
007: * General Public License Version 2 only ("GPL") or the Common
008: * Development and Distribution License("CDDL") (collectively, the
009: * "License"). You may not use this file except in compliance with the
010: * License. You can obtain a copy of the License at
011: * http://www.netbeans.org/cddl-gplv2.html
012: * or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
013: * specific language governing permissions and limitations under the
014: * License. When distributing the software, include this License Header
015: * Notice in each file and include the License file at
016: * nbbuild/licenses/CDDL-GPL-2-CP. Sun designates this
017: * particular file as subject to the "Classpath" exception as provided
018: * by Sun in the GPL Version 2 section of the License file that
019: * accompanied this code. If applicable, add the following below the
020: * License Header, with the fields enclosed by brackets [] replaced by
021: * your own identifying information:
022: * "Portions Copyrighted [year] [name of copyright owner]"
023: *
024: * Contributor(s):
025: *
026: * The Original Software is NetBeans. The Initial Developer of the Original
027: * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
028: * Microsystems, Inc. All Rights Reserved.
029: *
030: * If you wish your version of this file to be governed by only the CDDL
031: * or only the GPL Version 2, indicate your decision by adding
032: * "[Contributor] elects to include this software in this distribution
033: * under the [CDDL or GPL Version 2] license." If you do not indicate a
034: * single choice of license, a recipient has the option to distribute
035: * your version of this file under either the CDDL, the GPL Version 2 or
036: * to extend the choice of license to its licensees as provided above.
037: * However, if you add GPL Version 2 code and therefore, elected the GPL
038: * Version 2 license, then the option applies only if the new code is
039: * made subject to such option by the copyright holder.
040: */
041: package org.openide.xml;
042:
043: import org.openide.util.*;
044: import org.xml.sax.*;
045:
046: import java.io.*;
047:
048: import java.util.*;
049:
050: import javax.swing.event.*;
051:
052: /**
053: * Entity resolver resolving all entities registered by modules.
054: * Use {@link #getDefault} to get the master instance in system. Any parser working with
055: * unknown XML documents should use it to avoid unnecessary Internet
056: * connections.
057: *
058: * <p>You can register your own instances via lookup to add to the resolver pool,
059: * for example using an XML file in the format defined by {@link #PUBLIC_ID},
060: * but for reasons of performance and predictability during startup it is best to provide
061: * the entity (e.g. some DTD you define) as the contents of a file in
062: * the system filesystem, in the <samp>/xml/entities/</samp> folder, where the file path
063: * beneath this folder is based on the public ID as follows:
064: * <ol>
065: * <li>US-ASCII alphanumeric characters and '_' are left as is.
066: * <li>Spaces and various punctuation are converted to '_' (one per character).
067: * <li>Initial '-//' is dropped.
068: * <li>Final '//EN' is dropped.
069: * <li>Exactly two forward slashes in a row are converted to one.
070: * </ol>
071: * Thus for example the public ID <samp>-//NetBeans//Entity Mapping Registration 1.0//EN</samp>
072: * would be looked for in the file <samp>/xml/entities/NetBeans/Entity_Mapping_Registration_1_0</samp>.
073: * Naturally this only works if you are defining a fixed number of entities.
074: * <p>It is recommended that the entity file in <samp>/xml/entities/</samp> also be given a file
075: * attribute named <code>hint.originalPublicID</code> with a string value giving the public ID.
076: *
077: * @author Petr Kuzel
078: * @since release 3.2
079: */
080: public abstract class EntityCatalog implements EntityResolver {
081: /**
082: * DOCTYPE public ID defining grammar used for entity registrations.
083: */
084: public static final String PUBLIC_ID = "-//NetBeans//Entity Mapping Registration 1.0//EN"; // NOI18N
085: private static EntityCatalog instance = new Forwarder();
086:
087: /** Get a master entity catalog which can delegate to any others that have
088: * been registered via lookup.
089: */
090: public static EntityCatalog getDefault() {
091: return instance;
092: }
093:
094: /**
095: * This catalog is forwarding implementation.
096: */
097: private static class Forwarder extends EntityCatalog {
098: private Lookup.Result<EntityCatalog> result;
099:
100: Forwarder() {
101: }
102:
103: public InputSource resolveEntity(String publicID,
104: String systemID) throws IOException, SAXException {
105: if (result == null) {
106: Lookup.Template<EntityCatalog> temp = new Lookup.Template<EntityCatalog>(
107: EntityCatalog.class);
108: result = Lookup.getDefault().lookup(temp);
109: }
110:
111: for (EntityCatalog res : result.allInstances()) {
112: // using resolver's method because EntityCatalog extends EntityResolver
113: InputSource is = res.resolveEntity(publicID, systemID);
114:
115: if (is != null) {
116: return is;
117: }
118: }
119:
120: return null;
121: }
122: }
123: }
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