Bug 123040 [Commands] request: display help topic
I'm going to attach a patch to "command-ify" the opening of help topics. The command takes a parameter which is the href of a help topic. The default handler uses IWorkbenchHelpSystem.displayHelpResource(String) with the href parameter. If no parameter was given, the default handler calls IWorkbenchHelpSystem.displayHelp() instead to simply open the help system. Note that this looks like it should be opened against User Assistance, but the plugins that should be patched (I think) are org.eclipse.ui and org.eclipse.ui.workbench, so I opened against UI.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/ParameterizedCommand.java
public final Map getParameterMap() {
		if ((parameterizations == null) || (parameterizations.length == 0)) {
			return Collections.EMPTY_MAP;
		}
		final Map parameterMap = new HashMap();
		for (int i = 0; i < parameterizations.length; i++) {
			final Parameterization parameterization = parameterizations[i];
			parameterMap.put(parameterization.getParameter().getId(),
					parameterization.getValue());
		}
		return parameterMap;
	}
	/* (non-Javadoc)
	 * @see java.lang.Object#hashCode()
	 */
	public final int hashCode() {
		if (hashCode == HASH_CODE_NOT_COMPUTED) {
			hashCode = HASH_INITIAL * HASH_FACTOR + Util.hashCode(command);
			hashCode = hashCode * HASH_FACTOR
					+ Util.hashCode(parameterizations);
			if (hashCode == HASH_CODE_NOT_COMPUTED) {
				hashCode++;
			}
		}
		return hashCode;
	}
	/**
	 * Returns a {@link String} containing the command id, parameter ids and
	 * parameter values for this {@link ParameterizedCommand}. The returned
	 * {@link String} can be stored by a client and later used to recontruct an