Updating a java map entry

Question

Hi,

I'm facing a problem that seems to have no straighforward solution.

I'm using java.util.Map, and I want to update the value in a Key-Value pair.

Right now, I'm doing it lik this:

private Map<String,int> table = new HashMap<String,int>();
public void update(String key, int val) {
    if( !table.containsKey(key) ) return;
    Entry<String,int> entry;
    for( entry : table.entrySet() ) {
        if( entry.getKey().equals(key) ) {
            entry.setValue(val);
            break;
        }
    }
}

So is there any method so that I can get the required Entry object without having to iterate through the entire Map? Or is there some way to update the entry's value in place? Some method in Map like setValue(String key, int val)?

jrh

Answer 1

What's wrong with just

table.put(key, val);

?

Answer 2

You just use the method

public Object put(Object key, Object value)

if the key was already present in the Map then the previous value is returned.

Answer 3

If key is present table.put(key, val) will just overwrite the value else it'll create a new entry. Poof! and you are done. :)

you can get the value from a map by using key is table.get(key); Thats about it