Convert Linkedlist to ArrayList

Question

I had to write a program to do LZWDecode and I decided to use LinkedList to write the LZWDecode program below but I want to convert it to an ArrayList. Anyone have idea on how I can convert the LinkedList to an ArrayList to make it simpler. Thanks.

import java.util.*;

public class LZWDecoder {

private final int CLEAR_TABLE=256;
private final int END_OF_DATA=257;
private final int TABLE_SIZE=4096;

private static LinkedList<Integer> input = new LinkedList<Integer>();
@SuppressWarnings("unchecked")
private LinkedList<Integer>[] table
        = new LinkedList[TABLE_SIZE];
private LinkedList<Integer> temp = new LinkedList<Integer>();
private int index = 258;
private LinkedList<String> trace = new LinkedList<String>();
private boolean view = true;

private void enterData() {
Scanner scan = new Scanner(System.in);
System.out.println("Please enter the Input Code (EOD = 257):");
int n=0;
while(n!=END_OF_DATA && scan.hasNextInt()){
n = scan.nextInt();
//System.out.println("Adding "+n);
input.add(n);
}

System.out.println("Decoding...\nOutput:");
String code="";
for(int i=0; i<input.size(); i++) {
code+=input.get(i)+" ";
}
trace.add("\nInput: "+code);
//test
/*
while(!input.isEmpty()) {
System.out.println(input.remove());
}
*/
}

private void reset() {
trace.add("Clearing...");
//table.clear();
for(int i=0; i<TABLE_SIZE;i++) {
table[i] = new LinkedList<Integer>();
}
}

private void decode(int c) {
switch(c) {
case CLEAR_TABLE:
trace.add("decode\t"+CLEAR_TABLE+"->[256]");
reset();
break;
case END_OF_DATA:
trace.add("decode\t"+END_OF_DATA+"->[257]");
trace.add("Decoding finished.");
break;
default:
if(c<256) {
trace.add("decode\t"+c+"->["+c+"]");
if(!temp.isEmpty()) append(c);
emit(c);
add(temp);
} else {
trace.add("decode\t"+c+"->["+printTableNode(table[c])+"]");
if(!temp.isEmpty()) append(table[c].get(0));
emit(c, table[c]);
add(temp);
}
}
}

private void emit(int n, LinkedList<Integer> c) {
//int [] a=new int[c.size()];
temp=new LinkedList<Integer>();
for(int i=0; i<c.size(); i++) {
//a[i]=c.get(i);
System.out.print(c.get(i)+" ");
temp.add(c.get(i));
}
trace.add("emit\t"+n+"->"+"["+printTableNode(c)+"]");

}

private void emit(int c) {
//print out output
temp=new LinkedList<Integer>();
temp.add(c);
trace.add("emit\t"+c+"->"+"["+c+"]");
System.out.print(c+" ");
}

/*
private void add(int c) {
//added to table is copied to temp
table[index].add(c);
temp = (LinkedList)table[index].clone();
trace.add("add\t"+index+"->["+printTableNode(table[index])+"]");
}
*/

private void add(LinkedList<Integer> c) {
for(int i=0; i<c.size();i++) {
//temp.add(c.get(i));
table[index].add(c.get(i));
}
trace.add("add\t"+index+"->["+printTableNode(table[index])+"]");
}


private void append(int c) {
//table[c].add(12);//add what?
//temp.add(c);
table[index].add(c);
trace.add("append\t"+index+"->["+printTableNode(table[index])+"]");
index++;
}

private String printTableNode(LinkedList l) {
String list="";
for(int i=0; i<l.size();i++) {
list+=l.get(i);
if(i<l.size()-1) {
list+=", ";
}
}
    return list;
}

private void printTrace() {
System.out.print("Printing Trace...");
for(int i=0; i<trace.size(); i++) {
System.out.println(trace.get(i));
}
}

public static void main(String[] args) {
// TODO code application logic here
LZWDecoder d = new LZWDecoder();
d.enterData();
while(!input.isEmpty()) {
d.decode(input.remove());
}
System.out.print("\n\n");
d.printTrace();
}

}

Answer 1

Question is not clear enough. Do you want to use ArrayList instead of Linked List? Or do you want to convert a Linked List to an ArrayList?

First of all please declare variables on their interface not on implementation,

i.e

    LinkedList<Integer>[] table = new LinkedList[TABLE_SIZE]; 

Instead use

    List<Integer>[] table = new LinkedList[TABLE_SIZE];

Please provide a little more details on what you really looking for ....

If you want an array List from another collection, do this,

   List<T> t = new ArrayList<>();
   t.addAll(linkedList);

Regards Lyju