source: trunk/greenstone3-extensions/gs3build/src/org/greenstone/gsdl3/gs3build/util/FileTrie.java@ 12188

package org.greenstone.gsdl3.gs3build.util;

import java.util.ArrayList;
import java.util.List;

import org.greenstone.gsdl3.gs3build.doctypes.DocumentID;

public class FileTrie
{   String   stem;
    List     childTries;
    List     childDocs;
    FileTrie parent;

    public FileTrie(String stem)
    {   this.childTries = new ArrayList();
        this.childDocs  = new ArrayList();
        this.stem = stem;
        this.parent = null;
    }

    public void setParent(FileTrie trie)
    {   this.parent = trie;
    }

    public FileTrie getParent()
    {   return this.parent;
    }

    public void addChild(FileTrie trie)
    {   trie.setParent(this);
        this.childTries.add(trie);
    }

    public void replaceChild(FileTrie oldChild, FileTrie newChild)
    {   for (int i = 0; i < this.childTries.size(); i ++)
        {   FileTrie thisChild = (FileTrie) this.childTries.get(i);
            if (thisChild == oldChild)
            {   this.childTries.set(i, newChild);
                return;
            }
        }
    }

    public void addDocument(DocumentID documentID)
    {   this.childDocs.add(documentID);
    }

    public boolean postDocument(String filename, DocumentID documentID)
    {   int common = 0;
        int i;
        
        while (common < filename.length() &&
               common < this.stem.length() &&
                      filename.charAt(common) == stem.charAt(common))
        {   common ++;
        }

        if (common == 0)
        { return false;
        }

        if (common == this.stem.length())
        {   // post it in this node
            filename = filename.substring(this.stem.length());

            // select which sub-trie to attempt...
            for (i = 0; i < this.childTries.size(); i ++)
            {   FileTrie child = (FileTrie) this.childTries.get(i);
                
                if (child.postDocument(filename, documentID))
                {   break;
                }
            }

            if (i == this.childTries.size())
            { FileTrie newChild = new FileTrie(filename);
                this.addChild(newChild);

                newChild.addDocument(documentID);
            }
        }
        else
        {   // divide this node at the 'common' point...
            FileTrie parentTrie = new FileTrie(this.stem.substring(0, common));
            this.parent.replaceChild(this, parentTrie);

            // truncate our root
            this.stem = this.stem.substring(common);

            // add ourselves to our new parent
            parentTrie.addChild(this);

            // trim back the file name
            filename = filename.substring(common);

            // recurse into posting the document
            this.postDocument(filename, documentID);
        }
        return true;
    }

    public boolean postFile(String filename)
    {   return this.postDocument(filename, null);
    }

    public List getDocuments(String filename)
    {   FileTrie leaf = this.getNode(filename);
        return leaf.childDocs;
    }

    public FileTrie getNode(String filename)
    {   int common = 0;
        int i;
        
        while (common < filename.length() &&
               common < this.stem.length() &&
                     filename.charAt(common) == stem.charAt(common))
        {   common ++;
        }

        if (common == 0)
        { return null;
        }

        if (common == this.stem.length())
        {   if (common == filename.length())
            {   return this;
            }

            filename = filename.substring(this.stem.length());

            // select which sub-trie to attempt...
            for (i = 0; i < this.childTries.size(); i ++)
            {   FileTrie child = (FileTrie) this.childTries.get(i);
                
                child = child.getNode(filename);

                if (child != null)
                {   return child;
                }
            }
        }
        return null;
    }
}