I currently face the following issue:
I am trying to refactor a recursive algorithm to an iterative one. What this recursive algorithm does is this:
method1 is passed some initial parameters. Based on a processing that takes place at the beginning of method1, method2 is invoked with these parameters. Now method2 uses some conditions and based on the one that is satisfied method1 is invoked again with the appropriate parameters.
Now, based on the answer on the link I've provided above I did the same thing. But I have to pass parameters around so I did this:
Stack<ArrayList<Object>> stack (the stack for the ArrayList<Object> objects)
ArrayList<Object> parametersForSync = new ArrayList<Object>();
ArrayList<Object> paramForHandle = new ArrayList<Object>();
(Each array list of objects is a list of the parameters to be passed to both the methods. The first array list is for the first method and the second for the second method.)
Assuming I pop and push array lists down the stack correctly I face the following issue which is my main problem and the reason of this question:
Within method2 I have to check whether the object (that was on the array list and is passed to the method) is an instanceof another class of mine. Now I have some conditions there which do not get satisfied when in fact they should.
Is this because of java's type erasure? Is there anyway to overcome this?
If am not clear at a certain point in my explanations please ask me to clarify.
Edit: What follows is the code that replaces the recursion that goes like this:
syncWithServer(parameter set x){
handleResultArray(parameter set y);
};
handleResultArray(parameter set ){
syncWithServer(parameter set w)
}
===========================================================
Stack<ArrayList<Object>> stack = new Stack<ArrayList<Object>>();
ArrayList<Object> paramList = new ArrayList<Object>();
paramList.add(oeHelper);
paramList.add(false);
paramList.add(domain);
paramList.add(null);
paramList.add(true);
paramList.add(10000);
paramList.add(true);
stack.push(paramList);
int counter = 0;
ArrayList<Object> parametersForSync = new ArrayList<Object>();
ArrayList<Object> paramForHandle = new ArrayList<Object>();
while (!stack.isEmpty()) {
Log.d(TAG, "Loop: " + counter);
parametersForSync = stack.pop();
paramForHandle = ((OEHelper) parametersForSync.get(0))
.syncWithServer(
// why error here?
(boolean) parametersForSync.get(1),
(OEDomain) parametersForSync.get(2),
(List<Object>) parametersForSync.get(3),
(boolean) parametersForSync.get(4),
(int) parametersForSync.get(5),
(boolean) parametersForSync.get(6));
parametersForSync = ((OEHelper) paramForHandle.get(3))
.handleResultArray(
(OEFieldsHelper) paramForHandle.get(0),
(JSONArray) paramForHandle.get(1),
(boolean) paramForHandle.get(2));
if (parametersForSync.size() != 0) {
stack.push(parametersForSync);
}
counter++;
Now the first method:
public ArrayList<Object> syncWithServer(boolean twoWay, OEDomain domain,
List<Object> ids, boolean limitedData, int limits,
boolean removeLocalIfNotExists) {
Log.d(TAG, "syncWithServer");
List<OEColumn> dbCols = mDatabase.getDatabaseColumns();
List<OEColumn> dbFinalList = new ArrayList<OEColumn>();
ArrayList<Object> parametersList = new ArrayList<Object>();
Log.d(TAG, "Columns & finalList created");
for (OEColumn col : dbCols) {
if (!mOne2ManyCols.contains(col.getName())) {
dbFinalList.add(col);
}
}
OEFieldsHelper fields = new OEFieldsHelper(dbFinalList);
try {
if (domain == null) {
domain = new OEDomain();
}
if (ids != null) {
domain.add("id", "in", ids);
}
if (limitedData) {
mPref = new PreferenceManager(mContext);
int data_limit = mPref.getInt("sync_data_limit", 60);
domain.add("create_date", ">=",
OEDate.getDateBefore(data_limit));
}
if (limits == -1) {
limits = 50;
}
Log.d(TAG, "*****.search_read() started");
JSONObject result = *****.search_read(mDatabase.getModelName(),
fields.get(), domain.get(), 0, limits, null, null);
Log.d(TAG, "***.search_read() returned");
mAffectedRows = result.getJSONArray("records").length();
parametersList.add(fields);
parametersList.add(result.getJSONArray("records"));
parametersList.add(removeLocalIfNotExists);
parametersList.add(OEHelper.this);
//This parametersList contains the parameters that must be used to invoke the next method
Now the second method:
=================================================
public ArrayList<Object> handleResultArray(
OEFieldsHelper fields, JSONArray results,
boolean removeLocalIfNotExists) {
Log.d(TAG, "handleResultArray");
ArrayList<Object> parametersList = new ArrayList<Object>();
// ArrayList<Object> parameterStack = new ArrayList<Object>();
try {
fields.addAll(results);
List<OERelationData> rel_models = fields.getRelationData();
Log.d(TAG, "rel_models: "+rel_models.size());
for (OERelationData rel : rel_models) {
// Handling many2many records
if (rel.getDb().getClass()==OEManyToMany.class
/*instanceof OEManyToMany*/) {//TODO type erasure?
Log.v(TAG, "Syncing ManyToMany Records");
OEManyToMany m2mObj = (OEManyToMany) rel.getDb();
OEHelper oe = ((OEDatabase) m2mObj.getDBHelper())
.getOEInstance();
parametersList.add(oe);
parametersList.add(false);
parametersList.add(null);
parametersList.add(rel.getIds());
parametersList.add(false);
parametersList.add(0);
parametersList.add(false);
return parametersList;
} else if (rel.getDb().getClass()==OEManyToOne.class
/*instanceof OEManyToOne*/) {
// Handling many2One records
Log.v(TAG, "Syncing ManyToOne Records");
// M2OCounter++;
OEManyToOne m2oObj = (OEManyToOne) rel.getDb();
OEHelper oe = ((OEDatabase) m2oObj.getDBHelper())
.getOEInstance();
parametersList.add(oe);
parametersList.add(false);
parametersList.add(null);
parametersList.add(rel.getIds());
parametersList.add(false);
parametersList.add(0);
parametersList.add(false);
// parametersMap.put(Counter, parametersList);
// parameterStack.add(parametersList);
return parametersList;
} else if (rel.getDb().getClass()==OEOneToMany.class
/*instanceof OEOneToMany*/) {
Log.v(TAG, "Syncing OneToMany Records");
// O2MCounter++;
OEOneToMany o2mObj = (OEOneToMany) rel.getDb();
OEHelper oe = ((OEDatabase) o2mObj.getDBHelper())
.getOEInstance();
oe.setOne2ManyCol(o2mObj.getColumnName());
parametersList.add(oe);
parametersList.add(false);
parametersList.add(null);
parametersList.add(rel.getIds());
parametersList.add(false);
parametersList.add(0);
parametersList.add(false);
// parametersMap.put(Counter, parametersList);
// parameterStack.add(parametersList);
return parametersList;
} else {
Log.v(TAG, "Syncing records with no relations"
+ rel.getDb().getClass().getSimpleName());
OEHelper oe = ((OEDatabase) rel.getDb()).getOEInstance();
parametersList.add(oe);
parametersList.add(false);
parametersList.add(null);
parametersList.add(rel.getIds());
parametersList.add(false);
parametersList.add(0);
parametersList.add(false);
return parametersList;//TODO when nothing matches this returns
}
}
List<Long> result_ids = mDatabase.createORReplace(
fields.getValues(), removeLocalIfNotExists);
mResultIds.addAll(result_ids);
mRemovedRecordss.addAll(mDatabase.getRemovedRecords());
} catch (Exception e) {
e.printStackTrace();
}
return parametersList;
}
The second method is supposed to return from within one of the conditions but none of the conditions is met
