// -- Creates a K-V pair. Key must be a string, Value is an object. Returns false if HashMap
// already full.
boolean set(String key, Object value) {
int index = Math.abs(key.hashCode() % this.MY_SIZE);
/*
First, check if key exists in the appropriate bucket.
If it does, overwrite value.
If not, then create new K-V pair in array.
*/
if (this.table[index] == null) {
if (this.NUM_ELEMENTS
== this.MY_SIZE) { // Check if HashMap full. If full, print to console, and return false.
System.out.println("ERROR: Trying to insert element in full CustomHashMap");
return false;
}
KVPairNode temp = new KVPairNode(key, value);
this.table[index] = temp;
this.NUM_ELEMENTS++;
return true;
} else {
KVPairNode start;
start = this.table[index];
while (start != null) {
if (start.theKey.equals(key)) { // Overwrite value. Don't increment NUM_ELEMENTS
start.theValue = value;
return true;
}
start = start.next;
}
if (this.NUM_ELEMENTS
== this.MY_SIZE) { // Check if HashMap full. If full, print to console, and return false.
System.out.println("ERROR: Trying to insert element in full CustomHashMap");
return false;
}
KVPairNode temp = new KVPairNode(key, value);
temp.next = this.table[index];
this.table[index] = temp;
this.NUM_ELEMENTS++;
return true;
}
}
// -- Deletes a K-V Pair from HashMap, returns the value deleted. Returns null and deletes nothing
// if key does not exist.
public Object delete(String key) {
KVPairNode theNode = this.getNode(key);
Object output;
/*
We want to "delete" this node.
If the next node is null, just make this current node null.
Else, copy the next Node's information into the current node.
*/
if (theNode != null) {
output = theNode.theValue;
if (theNode.next == null) {
theNode = null;
} else {
theNode.theKey = theNode.next.theKey;
theNode.theValue = theNode.next.theValue;
theNode.next = theNode.next.next;
}
this.NUM_ELEMENTS--;
return output;
} else {
System.out.println("ERROR: Key does not exist.");
return null;
}
}
