How to create a context sensitive help in a Java application

Create an eclipse RCP application and extend the eclipse editor.

With eclipse is very simple create an editor and add a content assist to it.

Look at this FAQ.

I don't know if I totally understand your question. I'm guessing you're doing this in swing. Are you looking for one of those awt hover-like things (sorry, that's aweful, I just can't quite remember what it's called) like Google has when you're typing a search?

I'm not sure whether I can help you with that, but here's a method I used to match objects against a search term based on any of their attributes' values using reflection. This may be something you don't need at all, but I thought just in case I could give it to you. Hope it helps!

 /** * Returns true if any attribute in the item matches the given constraints * * @param object the object you want to match * @param klass the class to get the fields from (in most cases you'll just call object.getClass()) * @param iterations how many inherited levels you want to check fields for * @param match the String to match fields against * @param ignoreField fieldNames you wish to ignore, you can give as many as you like, you can also give an * array of strings * @return whether the given object contained fields which matched the given string */ public static boolean matches(Object object, Class klass, int iterations, String match, String... ignoreField) { if (iterations < 0) { return false; } boolean checkMatch = false; try { checkMatch = matchFields(klass.getDeclaredFields(), object, match, ignoreField); } catch (IllegalArgumentException ex) { Logger.getLogger(OtherHelper.class.getName()).log(Level.SEVERE, null, ex); } catch (IllegalAccessException ex) { Logger.getLogger(OtherHelper.class.getName()).log(Level.SEVERE, null, ex); } if (checkMatch) { return true; } else { Class<? extends Object> supersSuperclass = (Class<? extends Object>) klass.getSuperclass(); if (supersSuperclass != Object.class) { boolean matches = matches(object, supersSuperclass, (iterations - 1), match, ignoreField); if (matches) { return true; } else { return false; } } else { return false; } } } /** * Calls matchField(field, bo, match) on each field in the given field array. * * @param fields the fields array to get the fields from * @param object the object to get the field values from * @param match the text to match fields to * @param ignoreField any number of fieldNames which are to be ignored. * @return true on first true field match * @throws IllegalArgumentException * @throws IllegalArgumentException * @throws IllegalAccessException */ private static boolean matchFields(Field[] fields, Object object, String match, String... ignoreField) throws IllegalArgumentException, IllegalArgumentException, IllegalAccessException { List<String> ignoreFieldsList = Arrays.asList(ignoreField); for (Field field : fields) { if (!ignoreFieldsList.contains(field.getName())) { if (matchField(field, object, match)) { return true; } } } return false; } /** * Gets the value of the field and matches the string version of it with the given match * * @param field the field to match * @param object the object to get the field value from * @param match the match to match the field value to. * @return * @throws IllegalArgumentException * @throws IllegalArgumentException * @throws IllegalAccessException */ private static boolean matchField(Field field, Object object, String match) throws IllegalArgumentException, IllegalArgumentException, IllegalAccessException { field.setAccessible(true); if (field.get(object) == null) { return false; } Class<?> type = field.getType(); String value = null; if (type == Date.class) { SimpleDateFormat sdf = new SimpleDateFormat("MMM d, yyyy"); Date date = (Date) field.get(object); value = sdf.format(date); } else if (type == String.class || isPrimitive(type)) { value = field.get(object).toString(); } if (value != null && Pattern.compile(Pattern.quote(match), Pattern.CASE_INSENSITIVE).matcher(value).find()) { return true; } else { return false; } } /** * Checks first whether it is primitive and then whether it's wrapper is a primitive wrapper. Returns true * if either is true * * @param c * @return whether it's a primitive type itself or it's a wrapper for a primitive type */ public static boolean isPrimitive(Class c) { if (c.isPrimitive()) { return true; } else if (c == Byte.class || c == Short.class || c == Integer.class || c == Long.class || c == Float.class || c == Double.class || c == Boolean.class || c == Character.class) { return true; } else { return false; } }