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
/**
 * <p>
 * A command that has had one or more of its parameters specified. This class
 * serves as a utility class for developers that need to manipulate commands
 * with parameters. It handles the behaviour of generating a parameter map and a
 * human-readable name.
 * </p>
 * 
 * @since 3.1
 */
public final class ParameterizedCommand implements Comparable {
	/**
	 * The constant integer hash code value meaning the hash code has not yet
	 * been computed.
	 */
	private static final int HASH_CODE_NOT_COMPUTED = -1;
	/**
	 * A factor for computing the hash code for all parameterized commands.
	 */
	private static final int HASH_FACTOR = 89;
	/**
	 * The seed for the hash code for all parameterized commands.
	 */
	private static final int HASH_INITIAL = ParameterizedCommand.class
			.getName().hashCode();
	/**
	 * The index of the parameter id in the parameter values.
	 * 
	 * @deprecated no longer used
	 */