/*
* GeoSolutions map - Digital field mapping on Android based devices
* Copyright (C) 2013 GeoSolutions (www.geo-solutions.it)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package it.geosolutions.android.map.loaders;
import it.geosolutions.android.map.model.Layer;
import it.geosolutions.android.map.model.Source;
import it.geosolutions.android.map.model.query.FeatureInfoQueryResult;
import it.geosolutions.android.map.model.query.FeatureInfoTaskQuery;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.support.v4.content.AsyncTaskLoader;
import android.util.Log;
/**
* Async query task to query layers. Updates an adapter with the results from a
* query A query to the task is a "List of Lists of Maps", implemented with a
* bundle of bundles The main bundle contains is name->list of features feature
* contains name->value bundles
*
* @author Lorenzo Natali (www.geo-solutions.it)
*/
public class FeatureInfoLoader extends
AsyncTaskLoader<List<FeatureInfoQueryResult>> {
int features_loaded = 0;
private List<FeatureInfoQueryResult> mData;
private FeatureInfoTaskQuery[] queryQueue;
// private FeatureInfoObserver mObserver;
private static int MAX_FEATURES = 10;
/**
* Constructor for class FeatureInfoLoader with FeatureInfoTaskQuery
* @param ctx
* @param queryQueue
*/
public FeatureInfoLoader(Context ctx, FeatureInfoTaskQuery[] queryQueue) {
// Loaders may be used across multiple Activities (assuming they aren't
// bound to the LoaderManager), so NEVER hold a reference to the context
// directly. Doing so will cause you to leak an entire Activity's context.
// The superclass constructor will store a reference to the Application
// Context instead, and can be retrieved with a call to getContext().
super(ctx);
this.queryQueue = queryQueue;
}
protected void doInBackground(FeatureInfoTaskQuery[] queryQueue,
List<FeatureInfoQueryResult> data) {
Log.d("FEATURE_INFO_TASK", "Info Task Launched");
//process all queries
for (FeatureInfoTaskQuery query : queryQueue) {
if (!processQuery(query, data)) {
return;
}
}
return;
}
/**
* Process a single <FeatureInfoQuery>
* @param query
* @param data the result will be added to this array
*/
private boolean processQuery(FeatureInfoTaskQuery query,
List<FeatureInfoQueryResult> data) {
Layer<?> l = query.getLayer();
Source s = l.getSource();
features_loaded += s.performQuery(query, data);
return true;
}
/*
* (non-Javadoc)
* @see android.support.v4.content.AsyncTaskLoader#loadInBackground()
*/
@Override
public List<FeatureInfoQueryResult> loadInBackground() {
List<FeatureInfoQueryResult> data = new ArrayList<FeatureInfoQueryResult>();
// TODO: Perform the query here and add the results to 'data'.
doInBackground(queryQueue, data);
return data;
}
// ********************************************************/
// ** Deliver the results to the registered listener **/
// ********************************************************/
@Override
public void deliverResult(List<FeatureInfoQueryResult> data) {
if (isReset()) {
// The Loader has been reset; ignore the result and invalidate the data.
releaseResources(data);
return;
}
// Hold a reference to the old data so it doesn't get garbage collected.
// We must protect it until the new data has been delivered.
List<FeatureInfoQueryResult> oldData = mData;
mData = data;
if (isStarted()) {
// If the Loader is in a started state, deliver the results to the
// client. The superclass method does this for us.
super.deliverResult(data);
}
// Invalidate the old data as we don't need it any more.
if (oldData != null && oldData != data) {
releaseResources(oldData);
}
}
// ********************************************************/
// ** Implement the Loader's state-dependent behavior **/
// ********************************************************/
@Override
protected void onStartLoading() {
if (mData != null) {
// Deliver any previously loaded data immediately.
deliverResult(mData);
}
// Begin monitoring the underlying data source.
// if (mObserver == null) {
// mObserver = new SampleObserver();
// // TODO: register the observer
// }
if (takeContentChanged() || mData == null) {
// When the observer detects a change, it should call onContentChanged()
// on the Loader, which will cause the next call to takeContentChanged()
// to return true. If this is ever the case (or if the current data is
// null), we force a new load.
forceLoad();
}
}
/*
* (non-Javadoc)
* @see android.support.v4.content.Loader#onStopLoading()
*/
@Override
protected void onStopLoading() {
cancelLoad();
}
/*
* (non-Javadoc)
* @see android.support.v4.content.Loader#onReset()
*/
@Override
protected void onReset() {
onStopLoading();
if (mData != null) {
releaseResources(mData);
mData = null;
}
// if(mObserver !=null){
// //TODO unregister the observer
// moObserver=null;
//
// }
}
/*
* (non-Javadoc)
* @see android.support.v4.content.AsyncTaskLoader#onCanceled(java.lang.Object)
*/
@Override
public void onCanceled(List<FeatureInfoQueryResult> data) {
// TODO Auto-generated method stub
super.onCanceled(data);
releaseResources(data);
}
/**
* @param data
*/
private void releaseResources(List<FeatureInfoQueryResult> data) {
// release resource if needed
}
}