DbUtil.java

package org.commcare.android.database;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

import org.commcare.util.externalizable.ImprovedPrototypeFactory;
import org.javarosa.core.util.PrefixTree;
import org.javarosa.core.util.externalizable.Externalizable;
import org.javarosa.core.util.externalizable.PrototypeFactory;

import android.content.Context;
import dalvik.system.DexFile;

public class DbUtil {
    
    public static String ID_COL = "commcare_sql_id";
    public static String DATA_COL = "commcare_sql_record";
    
    private static PrototypeFactory factory;


    public static PrototypeFactory getPrototypeFactory(Context c) {
        if(factory != null) {
            return factory;
        }
        
        PrefixTree tree = new PrefixTree();
        
        try {
        List<String> classes = getClasses(new String[] { "org.javarosa", "org.commcare"}, c);
        for(String cl : classes) {
            tree.addString(cl);
        }
        } catch(Exception e) {
            throw new RuntimeException(e);
        }
        
        
        factory = new ImprovedPrototypeFactory(tree);
        return factory;
        
    }
    
    /* Scans all classes accessible from the context class loader which belong to the given package and subpackages.
    *
    * @param packageName The base package
    * @return The classes
    * @throws ClassNotFoundException
    * @throws IOException
    */
   @SuppressWarnings("unchecked")
    private static List<String> getClasses(String[] packageNames, Context c)
           throws IOException 
   {
       ArrayList<String> classNames = new ArrayList<String>();
       
       String zpath = c.getApplicationInfo().sourceDir;
       
       
       if(zpath == null) {
           zpath = "/data/app/org.commcare.android.apk";
       }
       
       DexFile df = new DexFile(new File(zpath));
       for(Enumeration<String> en = df.entries() ; en.hasMoreElements() ;) {
           String cn = en.nextElement();
           try{
               for(String packageName : packageNames) {

                   if(cn.startsWith(packageName) && !cn.startsWith("org.commcare.dalvik") && !cn.contains(".test.") && !cn.contains("readystatesoftware") ) {
                       
                       //TODO: These optimize by preventing us from statically loading classes we don't need, but they take a _long_ time to run. 
                       //Maybe we should skip this and/or roll it into initializing the factory itself.
                       Class prototype = Class.forName(cn);
                       if(prototype.isInterface()) {
                           continue;
                       }
                       boolean emptyc = false;
                       for(Constructor<?> cons : prototype.getConstructors()) {
                           if(cons.getParameterTypes().length == 0){
                               emptyc = true;
                           }
                       }
                       if(!emptyc) {
                           continue;
                       }
                       if(Externalizable.class.isAssignableFrom(prototype)) {
                           classNames.add(cn);
                       }
                       classNames.add(cn);
                   }
               }
           } catch(IllegalAccessError e) {
               //nothing
           } catch (SecurityException e) {
               
           } catch(Exception e) {
               
           } catch(Error e) {
               
           }
       }
       
       return classNames;
   }
}