Name: krT82822 Date: 10/29/99


java version "1.2.2"
HotSpot VM (1.0.1, mixed mode, build g)
The java.util.ResourceBundle class needs to provide a way to determine if
it contains a resource for a given key, without necesarily fetching the
resource. Currently, if getObject(String) is called and there is no resource
associated with the given key, then ResourceBundle throws a
MissingResourceException. The cost of throwing and catching the exception is too
high if all you want to know is whether or not the key is valid.

I suggest adding two new methods to the ResourceBundle API. The first is a
public, final method which correctly handles inherited resources from the
bundle's parent. The other is a protected method which the user may override for
the specific type of resource bundle in question.


// Added to java.util.ResourceBundle

public final boolean hasKey(String key) {
    return handleHasKey(key) || parent.hasKey(key);
}


protected boolean handleHasKey(String key) {
    // The default implementation relies on getKeys()
    // Sub-classes are strongly encouraged to provide a better implementation
    Enumeration enum = getKeys();
    while (enum.hasMoreElements()) {
        if (key.equals(enum.nextElement())) {
            return true;
        }
    }
    return false;
}


NOTE: The above implementation of handleHasKey(String) has a flaw in it. It uses
the getKeys() method which will cause it to search ALL the keys, not just those
in this resource bundle. However, if bug #4095319 is fixed according to my
suggestion (see my comment attached to the bug) then you can call
handleGetKeys() instead and get the correct semantics.
(Review ID: 97177)
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