Databases
StackOverflow2013
Postsdbo
POOptimizing space usage in a trie structure in a java program
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POOptimizing space usage in a trie structure in a java program
    primarykey
    data
    text
    <p>I am trying to implement a trie structure in Java with 203675 words for a text editor.</p> <p>Before, I was using ArrayList to store the words and that was taking 90 megabytes of space. So I want to use a trie to minimize space consumption.</p> <p>Here is what I have so far, but now space consumption is 250 megabytes. What is the reason for this increase?</p> <pre><code>package TextEditor; import java.io.*; import java.util.*; import javax.swing.JOptionPane; class Vertex { int words; Map&lt;Character, Vertex&gt; child; public Vertex() { words = 0; child = new HashMap&lt;&gt;(); } } class Trie { private Vertex root; private InputStream openFile; private OutputStream openWriteFile; private BufferedReader readFile; private BufferedWriter writeFile; public Trie() { root = new Vertex(); } public Trie(String path) { try { root = new Vertex(); openFile = getClass().getResourceAsStream(path); readFile = new BufferedReader( new InputStreamReader(openFile)); String in = readFile.readLine(); while(readFile.ready()) { this.insert(in); try { in = readFile.readLine(); } catch (IOException ex) { JOptionPane.showMessageDialog(null, "TRIE CONSTRUCTION ERROR!!!!"); } } } catch (IOException ex) { JOptionPane.showMessageDialog(null, "TRIE CONSTRUCTION ERROR!!!!"); } } private void addWord(Vertex vertex, String s, int i) { try { if(i&gt;=s.length()) { vertex.words += 1; return; } char ind = s.charAt(i); if(!vertex.child.containsKey(ind)) { vertex.child.put(ind, new Vertex()); } addWord(vertex.child.get(ind), s, i+1); } catch(Exception e) { e.printStackTrace(); System.exit(1); } } final void insert(String s) { addWord(root, s.toLowerCase(), 0); } private void DFS(Vertex v, String s, ArrayList list, boolean store, String startsWith, int ind) { if(v != null &amp;&amp; v.words != 0) { if(!store) { System.out.println(s); } else { if(s.length() &gt;= startsWith.length()) { list.add(s); } } } for (Map.Entry&lt;Character, Vertex&gt; entry : v.child.entrySet()) { Character c = entry.getKey(); if((startsWith == null) || (ind&gt;=startsWith.length()) || (startsWith.charAt(ind) == c)) { DFS(v.child.get(c), s + c, list, store, startsWith, ind+1); } } } public void Print() { DFS(root, new String(""), null, false, null, 0); } ArrayList&lt;String&gt; getAsList(String startsWith) { ArrayList ret = new ArrayList(); DFS(root, new String(""), ret, true, startsWith, 0); return ret; } int count(Vertex vertex, String s, int i) { if(i &gt;= s.length()) { return vertex.words; } if(!vertex.child.containsKey(s.charAt(i))) { return 0; } return count(vertex.child.get(s.charAt(i)), s, i+1); } int count(String s) { return count(root, s, 0); } } </code></pre> <p>Is there a working example of a trie structure I can use?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USEric Leschinski
    1. USTamojit Chatterjee
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POOptimizing space usage in a trie structure in a java program
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POOptimizing space usage in a trie structure in a java program
      1. This table or related slice is empty.
      1. VTDownMod
    1. COYou may want to use the Flyweight design pattern to store your characters. If each character is a separate object, you will get an explosion of memory usage. More information here: http://www.oodesign.com/flyweight-pattern.html
      singulars
      1. POOptimizing space usage in a trie structure in a java program
      1. USMartin Wickham
    2. COTHe [tag:netbeans] tag and the reference to NetBeans in your title have been removed as your coding problem has *nothing* to do with NetBeans. You're not "programming with NetBeans", but rather you're programming with Java.
      singulars
      1. POOptimizing space usage in a trie structure in a java program
      1. USHovercraft Full Of Eels
    3. COGenerally, in heap issue situations, you could try two approaches: either runtime profiling, or getting a heap dump and analyzing that. That tells it for sure how much is being actually consumed. Also keep in mind that there is garbage collection happening - or not happening in the background...
      singulars
      1. POOptimizing space usage in a trie structure in a java program
      1. USppeterka
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload