LinkMigrationHelperImpl.java

package org.sakaiproject.util.impl;

import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.Vector;
import java.util.Map.Entry;
import org.sakaiproject.component.cover.ServerConfigurationService;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;



public class LinkMigrationHelperImpl implements org.sakaiproject.util.api.LinkMigrationHelper{
	private final String ESCAPED_SPACE= "%"+"20";
	private final String ASSIGNMENT_LINK_SIG = "assignment";
	private final String FORUM_LINK_SIG = "forum";

	
	private static final Log LOG = LogFactory.getLog(LinkMigrationHelperImpl.class);

	public void init(){
		
	}
	
	public String bracketAndNullifySelectedLinks(String m) throws Exception {
		
		String lbTmp = ServerConfigurationService.getString("LinkMigrationHelper.linksToBracket","assignment,forum");
		String[] linksToBracket = lbTmp.split(",");
		String lnTmp = ServerConfigurationService.getString("LinkMigrationHelper.linksToNullify","sam_pub,/posts/");
		String[] linksToNullify = lnTmp.split(",");
		List existingLinks = findLinks(m);
		Iterator l = existingLinks.iterator();
		while(l.hasNext()){
			
			String nextLink = (String) l.next();
			boolean bracketIt = matchLink(nextLink, linksToBracket);
			boolean nullIt = matchLink(nextLink, linksToNullify);
			if(bracketIt | nullIt){
				String replacementForLink = null;
				if(bracketIt){
					replacementForLink = nextLink;
				}else{
					replacementForLink = findLinkContent(nextLink);
				}
				int li = m.indexOf(nextLink);
				String before = m.substring(0, li);
				String after = m.substring(li+nextLink.length());
				StringBuffer replacementBuffer = new StringBuffer();
				replacementBuffer.append(before);
				replacementBuffer.append(" [");
				replacementBuffer.append(replacementForLink);
				replacementBuffer.append("] ");
				replacementBuffer.append(after);
				m=replacementBuffer.toString();
				
			}			
		}		
		return m;
	}
	
	private boolean matchLink(String link, String[] matches){
		
		for(int s = 0; s< matches.length; s++){
			String nextKey = matches[s];
			if(link.indexOf(nextKey)>0) return true;
		}
		return false;
	}
	
	public String migrateAllLinks(Set entrySet, String msgBody){
		Iterator<Entry<String, String>> entryItr = entrySet.iterator();
		while(entryItr.hasNext()) {
			Entry<String, String> entry = (Entry<String, String>) entryItr.next();
			String fromContextRef = entry.getKey();
			String targetContextRef = entry.getValue();
			msgBody =migrateOneLink(fromContextRef, targetContextRef, msgBody);
		}
		try {
			msgBody = bracketAndNullifySelectedLinks(msgBody);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			LOG.debug ("Forums LinkMigrationHelper.editLinks failed" + e);
		}
		return msgBody;
	}
	
	public String migrateOneLink(String fromContextRef, String targetContextRef, String msgBody){

		
		fromContextRef=fromContextRef.replace(" ",ESCAPED_SPACE);
		targetContextRef = targetContextRef.replace(" ",ESCAPED_SPACE);
//		logger.debug("fromContextRef:"+fromContextRef+"="+entry.getValue());
//		logger.debug("entry.getValue="+entry.getValue());
		if(msgBody.contains(fromContextRef)){
//			logger.debug("found a match");
			msgBody = msgBody.replace(fromContextRef, targetContextRef);
		}								
		return msgBody;
	}
	
	private List findLinks(String msgBody) throws Exception {
		
		Vector links = new Vector();
		int nextLinkAt = 0;
		nextLinkAt = msgBody.indexOf("<a", nextLinkAt);
		boolean done = false;
		if(nextLinkAt<0){
			done=true;
		}
		while(!done){
			
			int closingTagLocation = msgBody.indexOf("</a>", nextLinkAt);
			if(closingTagLocation<0){
				throw new Exception("unbalanced anchor tag");
			}else{
				String thisAnchor = msgBody.substring(nextLinkAt, closingTagLocation+4);
				links.add(thisAnchor);
			}
			nextLinkAt = msgBody.indexOf("<a", closingTagLocation+4);
			if(nextLinkAt<0){
				done=true;
			}
		}
		return links;
	}
	
	private String findLinkContent(String link) throws Exception {
		int contentStart = link.indexOf(">");
		int contentEnd = link.indexOf("</a>", contentStart);
		return link.substring(contentStart+1, contentEnd);
	}
	
	private String findLinkEntire(String link) throws Exception {
		int contentStart = link.indexOf("<");
		int contentEnd = link.indexOf("</a>", contentStart);
		return link.substring(contentStart+1, contentEnd);

	}

}