001: /**
002: * Copyright (c) 2003-2007, David A. Czarnecki
003: * All rights reserved.
004: *
005: * Redistribution and use in source and binary forms, with or without
006: * modification, are permitted provided that the following conditions are met:
007: *
008: * Redistributions of source code must retain the above copyright notice, this list of conditions and the
009: * following disclaimer.
010: * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
011: * following disclaimer in the documentation and/or other materials provided with the distribution.
012: * Neither the name of "David A. Czarnecki" and "blojsom" nor the names of its contributors may be used to
013: * endorse or promote products derived from this software without specific prior written permission.
014: * Products derived from this software may not be called "blojsom", nor may "blojsom" appear in their name,
015: * without prior written permission of David A. Czarnecki.
016: *
017: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
018: * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
019: * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
020: * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
021: * EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
022: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
023: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
024: * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
025: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
026: * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
027: * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
028: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
029: * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
030: */package org.blojsom.plugin.xpath;
031:
032: import org.apache.commons.jxpath.JXPathContext;
033: import org.apache.commons.logging.Log;
034: import org.apache.commons.logging.LogFactory;
035: import org.blojsom.blog.Blog;
036: import org.blojsom.blog.Entry;
037: import org.blojsom.plugin.Plugin;
038: import org.blojsom.plugin.PluginException;
039:
040: import javax.servlet.http.HttpServletRequest;
041: import javax.servlet.http.HttpServletResponse;
042: import java.util.ArrayList;
043: import java.util.Iterator;
044: import java.util.List;
045: import java.util.Map;
046:
047: /**
048: * XPathPlugin
049: *
050: * @author David Czarnecki
051: * @author Mark Lussier
052: * @version $Id: XPathPlugin.java,v 1.2 2007/01/17 02:35:07 czarneckid Exp $
053: * @since blojsom 3.0
054: */
055: public class XPathPlugin implements Plugin {
056:
057: private static final String XPATH_PARAM = "xpath";
058:
059: private Log _logger = LogFactory.getLog(XPathPlugin.class);
060:
061: /**
062: * Initialize this plugin. This method only called when the plugin is instantiated.
063: *
064: * @throws org.blojsom.plugin.PluginException
065: * If there is an error initializing the plugin
066: */
067: public void init() throws PluginException {
068: JXPathContext.newContext(Entry.class);
069: }
070:
071: /**
072: * Process the blog entries
073: *
074: * @param httpServletRequest Request
075: * @param httpServletResponse Response
076: * @param blog {@link Blog} instance
077: * @param context Context
078: * @param entries Blog entries retrieved for the particular request
079: * @return Modified set of blog entries
080: * @throws PluginException If there is an error processing the blog entries
081: */
082: public Entry[] process(HttpServletRequest httpServletRequest,
083: HttpServletResponse httpServletResponse, Blog blog,
084: Map context, Entry[] entries) throws PluginException {
085: Entry[] results;
086: String xpath = httpServletRequest.getParameter(XPATH_PARAM);
087:
088: if (xpath != null && !"".equals(xpath)) {
089: xpath = xpath.trim();
090:
091: if (_logger.isDebugEnabled()) {
092: _logger.debug("Attempting xpath query with: " + xpath);
093: }
094:
095: EntryWrapper entryWrapper = new EntryWrapper(entries);
096: List foundEntries = new ArrayList();
097: JXPathContext xpathcontext = JXPathContext
098: .newContext(entryWrapper);
099:
100: try {
101: Iterator entryIterator = xpathcontext.iterate(xpath);
102:
103: while (entryIterator.hasNext()) {
104: Object object = entryIterator.next();
105: Entry entry = (Entry) object;
106: foundEntries.add(entry);
107: }
108: } catch (Exception e) {
109: if (_logger.isErrorEnabled()) {
110: _logger.error(e);
111: }
112: }
113:
114: if (foundEntries.size() == 0) {
115: results = new Entry[0];
116: } else {
117: results = new Entry[foundEntries.size()];
118: for (int x = 0; x < foundEntries.size(); x++) {
119: results[x] = (Entry) foundEntries.get(x);
120: }
121: }
122: } else {
123: results = entries;
124: }
125:
126: return results;
127: }
128:
129: /**
130: * Perform any cleanup for the plugin. Called after {@link #process}.
131: *
132: * @throws PluginException If there is an error performing cleanup for this plugin
133: */
134: public void cleanup() throws PluginException {
135: }
136:
137: /**
138: * Called when BlojsomServlet is taken out of service
139: *
140: * @throws PluginException If there is an error in finalizing this plugin
141: */
142: public void destroy() throws PluginException {
143: }
144: }
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