Roland Thomas Lichti

Manchmal muss man einfach in einen vorhanden JNDI reinschauen, um herauszufinden, was dort eigentlich auf Entdeckung schlummert. Die folgende Klasse liefert einen formatierten Baum aus den JNDI-Eintragungen.

[java autolinks="false" collapse="false" firstline="1" gutter="true" htmlscript="false" light="false" padlinenumbers="false" smarttabs="true" tabsize="2" toolbar="true"]
package de.kaiserpfalzedv.office.common.jndi;

import javax.naming.InitialContext;
import javax.naming.NameClassPair;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
* A small utlitiy class to print the JNDI tree.
*
* @author klenkes {@literal <rlichti@kaiserpfalz-edv.de>}
* @version 1.0.0
* @since 2016-09-29
*/
public class JndiWalker {
private static final Logger LOG = LoggerFactory.getLogger(JndiWalker.class);

/**
* Walks the {@link InitialContext} with the entry point given and returns a string containing all sub entries.
*
* @param context The initial context to be printed.
* @param entryPoint The node to start with.
* @return A string containing the tree of the initial context (nodes including the leaves).
* @throws NamingException If the lookup failes for some unknown reason.
*/
public String walk(final InitialContext context, final String entryPoint) throws NamingException {
StringBuffer sb = new StringBuffer(" JNDI tree for '").append(entryPoint).append("': ");

LOG.trace("JNDI-Walker activated for entry point '{}' on: {}", entryPoint, context);
walk(sb, context, entryPoint, 0);

return sb.toString();
}

private void walk(
StringBuffer sb,
final InitialContext context,
final String name,
final int level
) throws NamingException {
NamingEnumeration ne;
try {
ne = context.list(name);
} catch (NamingException e) {
LOG.trace("Reached leaf of JNDI: {}", name);
return;
}

while (ne.hasMoreElements()) {
NameClassPair ncp = (NameClassPair) ne.nextElement();

printLevel(sb, level);

sb
.append(ncp.getName())
.append(" (").append(ncp.getClassName())
.append(", ").append(getNameInNamespace(ncp))
.append(", ").append(getRelativeFlag(ncp))
.append(")");

walk(sb, context, name + "/" + ncp.getName(), level + 4);
}
}

private void printLevel(StringBuffer sb, int level) {
sb.append("\n");
for (int i=0; i < level; i++) {
sb.append(" ");
}
}

private String getNameInNamespace(NameClassPair ncp) {
String nameInNamespace;
try {
nameInNamespace = ncp.getNameInNamespace();
} catch (UnsupportedOperationException e) {
nameInNamespace = "not-supported";
}
return nameInNamespace;
}

private String getRelativeFlag(NameClassPair ncp) {
String isRelative;
try {
isRelative = ncp.isRelative() ? "relative" : "fixed";
} catch (UnsupportedOperationException e) {
isRelative = "not-supported";
}
return isRelative;
}
}
[/java]

Die Basis für diese kleine Hilfsklasse war ein Blogeintrag von Anders Rudklaer Norgaard. Ich habe sie nur Servlet-unabhängig gemacht.