001: /*
002: * hgcommons 7
003: * Hammurapi Group Common Library
004: * Copyright (C) 2003 Hammurapi Group
005: *
006: * This program is free software; you can redistribute it and/or
007: * modify it under the terms of the GNU Lesser General Public
008: * License as published by the Free Software Foundation; either
009: * version 2 of the License, or (at your option) any later version.
010: *
011: * This program is distributed in the hope that it will be useful,
012: * but WITHOUT ANY WARRANTY; without even the implied warranty of
013: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014: * Lesser General Public License for more details.
015: *
016: * You should have received a copy of the GNU Lesser General Public
017: * License along with this library; if not, write to the Free Software
018: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
019: *
020: * URL: http://www.hammurapi.biz/hammurapi-biz/ef/xmenu/hammurapi-group/products/products/hgcommons/index.html
021: * e-Mail: support@hammurapi.biz
022: */
023: package biz.hammurapi.config;
024:
025: import biz.hammurapi.util.Attributable;
026:
027: /**
028: * Helper class to navigate context trees. Follows unix filesystem naming convention: / is a path separator,
029: * . is current element, .. is parent element, absolute path starts with /
030: * @author Pavel Vlasov
031: * @revision $Revision$
032: */
033: public abstract class PathNavigator implements Context {
034:
035: protected Object master;
036:
037: public PathNavigator(Object master) {
038: this .master = master;
039: }
040:
041: protected abstract Object getParent();
042:
043: protected abstract Object getChild(String name);
044:
045: public Object get(String name) {
046: try {
047: Object ret = lookup(name);
048: if (ret instanceof Service) {
049: ((Service) ret).start();
050: }
051:
052: if (ret instanceof Wrapper) {
053: ret = ((Wrapper) ret).getMaster();
054: }
055:
056: if (ret instanceof Service) {
057: ((Service) ret).start();
058: }
059:
060: return ret;
061: } catch (ConfigurationException e) {
062: throw new RuntimeConfigurationException(e);
063: }
064: }
065:
066: private Object lookup(String name) {
067: if (name.startsWith("/")) {
068: if (getParent() instanceof Context) {
069: return ((Context) getParent()).get(name);
070: }
071: return name.equals("/") ? master : get(name.substring(1));
072: } else if ("..".equals(name)) {
073: return getParent();
074: } else if (name.startsWith("../")) {
075: return (getParent() instanceof Context) ? ((Context) getParent())
076: .get(name.substring(3))
077: : null;
078: }
079:
080: int idx = name.indexOf('/');
081: if (idx == -1) {
082: if (name.startsWith("@") && master instanceof Attributable) {
083: return ((Attributable) master).getAttribute(name
084: .substring(1));
085: }
086:
087: return ".".equals(name) ? master : getChild(name);
088: }
089:
090: String nameElement = name.substring(0, idx);
091: Object child = ".".equals(nameElement) ? master
092: : getChild(nameElement);
093: if (child instanceof Context) {
094: return ((Context) child).get(name.substring(idx + 1));
095: }
096:
097: return null;
098: }
099:
100: /**
101: * @param master Master context.
102: * @param parent Parent object.
103: * @return Instance of PathNavigator.
104: */
105: public static Context newInstance(Context master,
106: final Object parent) {
107: return new PathNavigator(master) {
108:
109: protected Object getParent() {
110: return parent;
111: }
112:
113: protected Object getChild(String name) {
114: return ((Context) master).get(name);
115: }
116:
117: };
118: }
119:
120: }
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