--- a/gwt-client/src/main/java/org/dive4elements/river/client/client/ui/DatacageTwinPanel.java	Thu Jan 18 18:26:30 2018 +0100
+++ b/gwt-client/src/main/java/org/dive4elements/river/client/client/ui/DatacageTwinPanel.java	Thu Jan 18 18:32:30 2018 +0100
@@ -8,511 +8,56 @@
 
 package org.dive4elements.river.client.client.ui;
 
+import org.dive4elements.river.client.shared.model.DataList;
+import org.dive4elements.river.client.shared.model.User;
+
 import com.google.gwt.core.client.GWT;
-import com.google.gwt.user.client.rpc.AsyncCallback;
-
-import com.smartgwt.client.data.Record;
-import com.smartgwt.client.types.ListGridFieldType;
 import com.smartgwt.client.widgets.Canvas;
-import com.smartgwt.client.widgets.events.ClickEvent;
 import com.smartgwt.client.widgets.grid.ListGrid;
-import com.smartgwt.client.widgets.grid.ListGridField;
-import com.smartgwt.client.widgets.grid.ListGridRecord;
-import com.smartgwt.client.widgets.grid.events.RecordClickEvent;
-import com.smartgwt.client.widgets.grid.events.RecordClickHandler;
 import com.smartgwt.client.widgets.layout.HLayout;
 import com.smartgwt.client.widgets.layout.VLayout;
 
-import org.dive4elements.river.client.client.Config;
-import org.dive4elements.river.client.client.FLYSConstants;
-import org.dive4elements.river.client.client.event.StepForwardEvent;
-import org.dive4elements.river.client.client.services.LoadArtifactServiceAsync;
-import org.dive4elements.river.client.client.services.RemoveArtifactServiceAsync;
-import org.dive4elements.river.client.shared.model.Artifact;
-import org.dive4elements.river.client.shared.model.Collection;
-import org.dive4elements.river.client.shared.model.Data;
-import org.dive4elements.river.client.shared.model.DataItem;
-import org.dive4elements.river.client.shared.model.DataList;
-import org.dive4elements.river.client.shared.model.DefaultData;
-import org.dive4elements.river.client.shared.model.DefaultDataItem;
-import org.dive4elements.river.client.shared.model.Recommendation;
-import org.dive4elements.river.client.shared.model.Recommendation.Facet;
-import org.dive4elements.river.client.shared.model.Recommendation.Filter;
-import org.dive4elements.river.client.shared.model.User;
-
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-
-// TODO Probably better to branch off AbstractUIProvider.
-// TODO Merge with other datacage-widget impls.
 /**
- * Panel containing a Grid and a "next" button. The Grid is fed by a
+ * A {@link AbstractPairRecommendationPanel} that uses a 'TwinDatacage' in the help-input area.
  * DatacagePairWidget which is put in the input-helper area.
  */
-public class DatacageTwinPanel
-extends      TextProvider {
-
-    private static final long serialVersionUID = 8906629596491827857L;
-
-    protected static FLYSConstants MSG = GWT.create(FLYSConstants.class);
-
-    protected String dataName;
-
-    protected User user;
-
-    /** ListGrid that displays user-selected pairs to build differences with. */
-    protected ListGrid differencesList;
-
-    /**
-     * List to track previously selected but now removed pairs. (Needed to
-     * be able to identify artifacts that can be removed from the collection.
-     */
-    protected List<RecommendationPairRecord> removedPairs =
-        new ArrayList<RecommendationPairRecord>();
-
-    /** Service handle to clone and add artifacts to collection. */
-    LoadArtifactServiceAsync loadArtifactService = GWT.create(
-            org.dive4elements.river.client.client.services.LoadArtifactService.class);
-
-    /** Service to remove artifacts from collection. */
-    RemoveArtifactServiceAsync removeArtifactService = GWT.create(
-            org.dive4elements.river.client.client.services.RemoveArtifactService.class);
-
-
-    public DatacageTwinPanel(User user) {
-        super();
-        this.user = user;
-    }
-
-
-    /**
-     * Remove first occurrence of "[" and "]" (if both do occur).
-     * @param value String to be stripped of [] (might be null).
-     * @return input string but with [ and ] removed, or input string if no
-     *         brackets were found.
-     * @see StringUtil.unbracket
-     */
-    public static final String unbracket(String value) {
-        // null- guard.
-        if (value == null) return value;
-
-        int start = value.indexOf("[");
-        int end   = value.indexOf("]");
-
-        if (start < 0 || end < 0) {
-            return value;
-        }
-
-        value = value.substring(start + 1, end);
+public abstract class DatacageTwinPanel
+extends      AbstractPairRecommendationPanel {
 
-        return value;
-    }
-
-
-    /**
-     * Create a recommendation from a string representation of it.
-     * @param from string in format as shown above.
-     * @return recommendation from input string.
-     */
-    public Recommendation createRecommendationFromString(String from, String factory) {
-        // TODO Construct "real" filter.
-        String[] parts = unbracket(from).split(";");
-        Recommendation.Filter filter = new Recommendation.Filter();
-        Recommendation.Facet  facet  = new Recommendation.Facet(
-                parts[1],
-                parts[2]);
-
-        List<Recommendation.Facet> facets = new ArrayList<Recommendation.Facet>
-            ();
-        facets.add(facet);
-        filter.add("longitudinal_section", facets);
-        Recommendation r = new Recommendation(factory, parts[0],
-            this.artifact.getUuid(), filter);
-        r.setDisplayName(parts[3]);
-        return r;
-    }
-
+	private IDatacageTwinPanelInfo leftInfo;
+	private IDatacageTwinPanelInfo rightInfo;
 
-    /**
-     * Add RecomendationPairRecords from input String to the ListGrid.
-     */
-    public void populateGridFromString(String from, String factory){
-        // Split this string.
-        // Create according recommendations and display strings.
-        String[] recs = from.split("#");
-        if (recs.length % 2 != 0) return;
-        for (int i = 0; i < recs.length; i+=2) {
-            Recommendation minuend =
-                createRecommendationFromString(recs[i+0], factory);
-            Recommendation subtrahend =
-                createRecommendationFromString(recs[i+1], factory);
+	public static interface IDatacageTwinPanelInfo extends IRecommendationInfo
+	{
+		String getOuts();
+	}
+	
+	public DatacageTwinPanel(final User user, IValidator validator, final IDatacageTwinPanelInfo leftInfo, final IDatacageTwinPanelInfo rightInfo ) {
+		super(user, validator, leftInfo, rightInfo);
 
-            RecommendationPairRecord pr = new RecommendationPairRecord(
-                minuend, subtrahend);
-            // This Recommendation Pair comes from the data string and was thus
-            // already cloned.
-            pr.setIsAlreadyLoaded(true);
-            this.differencesList.addData(pr);
-        }
-    }
-
-
-    /**
-     * Creates the graphical representation and interaction widgets for the data.
-     * @param dataList the data.
-     * @return graphical representation and interaction widgets for data.
-     */
+		this.leftInfo = leftInfo;
+		this.rightInfo = rightInfo;
+	}
+	
     @Override
-    public Canvas create(DataList dataList) {
+    protected final Canvas createChooserWidgets(final Canvas widget, final DataList dataList, final User user, final ListGrid differencesList) {
         GWT.log("createData()");
 
-        Canvas widget = createWidget();
         Canvas submit = getNextButton();
 
         VLayout layout       = new VLayout();
         HLayout helperLayout = new HLayout();
-        helperLayout.addMember(new DatacagePairWidget(this.artifact,
-            user, "winfo_diff_twin_panel", differencesList));
+        
+        final String leftOuts = leftInfo.getOuts();
+        final String rightOuts = rightInfo.getOuts();
+        
+        helperLayout.addMember(new DatacagePairWidget(this.artifact, user, leftOuts, rightOuts, differencesList));
 
         layout.addMember(widget);
         layout.addMember(submit);
         layout.setMembersMargin(10);
         this.helperContainer.addMember(helperLayout);
 
-        populateGrid(dataList, "waterlevel");
-        return layout;
-    }
-
-    protected void populateGrid(DataList dataList, String factory) {
-        Data data     = dataList.get(0);
-        this.dataName = data.getLabel();
-        for (int i = 0; i < dataList.size(); i++) {
-            if (dataList.get(i) != null && dataList.get(i).getItems() != null) {
-                if (dataList.get(i).getItems() != null) {
-                    populateGridFromString(
-                        dataList.get(i).getItems()[0].getStringValue(),
-                        factory);
-                }
-            }
-        }
-    }
-
-
-    /**
-     * Validates the selection.
-     * @return List of internationalized errror messages (if any).
-     */
-    @Override
-    public List<String> validate() {
-        List<String> errors = new ArrayList<String>();
-        if (differencesList.getRecords().length == 0) {
-            errors.add(MSG.error_no_waterlevel_pair_selected());
-        }
-        // Check whether minuend and subtrahend are equal.
-        for (ListGridRecord record: differencesList.getRecords()) {
-            RecommendationPairRecord r = (RecommendationPairRecord) record;
-            if (r.getFirst().equals(r.getSecond())) {
-                errors.add(MSG.error_same_waterlevels_in_pair());
-            }
-        }
-
-        return errors;
-    }
-
-
-    /**
-     * Creates layout with grid that displays selection inside.
-     */
-    public Canvas createWidget() {
-        VLayout layout  = new VLayout();
-        differencesList = new ListGrid();
-
-        differencesList.setCanEdit(false);
-        differencesList.setCanSort(false);
-        differencesList.setShowHeaderContextMenu(false);
-        differencesList.setHeight(150);
-        differencesList.setShowAllRecords(true);
-
-        ListGridField nameField    = new ListGridField("first",  "Minuend");
-        ListGridField capitalField = new ListGridField("second", "Subtrahend");
-        // Track removed rows, therefore more or less reimplement
-        // setCanRecomeRecords.
-        final ListGridField removeField  =
-            new ListGridField("_removeRecord", "Remove Record"){{
-                setType(ListGridFieldType.ICON);
-                setIcon(GWT.getHostPageBaseURL() + MSG.removeFeature());
-                setCanEdit(false);
-                setCanFilter(false);
-                setCanSort(false);
-                setCanGroupBy(false);
-                setCanFreeze(false);
-                setWidth(25);
-        }};
-
-        differencesList.setFields(new ListGridField[] {nameField,
-           capitalField, removeField});
-
-        differencesList.addRecordClickHandler(new RecordClickHandler() {
-                @Override
-                public void onRecordClick(final RecordClickEvent event) {
-                    // Just handle remove-clicks
-                    if(!event.getField().getName().equals(removeField.getName())) {
-                        return;
-                    }
-                    trackRemoved(event.getRecord());
-                    event.getViewer().removeData(event.getRecord());
-                }
-            });
-        layout.addMember(differencesList);
-
         return layout;
     }
-
-
-    /**
-     * Add record to list of removed records.
-     */
-    public void trackRemoved(Record r) {
-        RecommendationPairRecord pr = (RecommendationPairRecord) r;
-        this.removedPairs.add(pr);
-    }
-
-    /**
-     * Set factory of recommendation such that the correct artifacts will
-     * be cloned for difference calculations.
-     */
-    public void adjustRecommendation(Recommendation recommendation) {
-        // XXX: THIS IS AN EVIL HACK TO MAKE W-DIFFERENCES WORK AGAIN!
-        // TODO: Throw all this code away and do it with server side recommendations!
-        recommendation.setTargetOut("w_differences");
-
-        if (recommendation.getIDs() != null) {
-            GWT.log("Setting staticwkms factory for rec with ID "
-                + recommendation.getIDs());
-            recommendation.setFactory("staticwkms");
-        }
-        /*
-        // So far, we do not need to rewrite the factory anymore,
-        // except for staticwkms; probably other cases will pop up later.
-        else if (recommendation.getFactory().equals("winfo")) {
-            GWT.log("Setting waterlevel factory for a winfo rec.");
-            recommendation.setFactory("waterlevel");
-        }
-        */
-        else {
-           GWT.log("Leave rec. id " + recommendation.getIDs() + ", factory "
-               + recommendation.getFactory() + " untouched.");
-        }
-    }
-
-    /**
-     * Validates data, does nothing if invalid, otherwise clones new selected
-     * waterlevels and add them to collection, forward the artifact.
-     */
-    @Override
-    public void onClick(ClickEvent e) {
-        GWT.log("DatacageTwinPanel.onClick");
-
-        List<String> errors = validate();
-        if (errors != null && !errors.isEmpty()) {
-            showErrors(errors);
-            return;
-        }
-
-        Config config = Config.getInstance();
-        String locale = config.getLocale();
-
-        ListGridRecord[] records = differencesList.getRecords();
-
-        List<Recommendation> ar  = new ArrayList<Recommendation>();
-        List<Recommendation> all = new ArrayList<Recommendation>();
-
-        for (ListGridRecord record : records) {
-            RecommendationPairRecord r =
-                (RecommendationPairRecord) record;
-            // Do not add "old" recommendations.
-            if (!r.isAlreadyLoaded()) {
-                // Check whether one of those is a dike or similar.
-                // TODO differentiate and merge: new clones, new, old.
-                Recommendation firstR = r.getFirst();
-                adjustRecommendation(firstR);
-
-                Recommendation secondR = r.getSecond();
-                adjustRecommendation(secondR);
-                ar.add(firstR);
-                ar.add(secondR);
-            }
-            else {
-                all.add(r.getFirst());
-                all.add(r.getSecond());
-            }
-        }
-
-        final Recommendation[] toClone = ar.toArray(new Recommendation[ar.size()]);
-        final Recommendation[] toUse   = all.toArray(new Recommendation[all.size()]);
-
-        // Find out whether "old" artifacts have to be removed.
-        List<String> artifactIdsToRemove = new ArrayList<String>();
-        for (RecommendationPairRecord rp: this.removedPairs) {
-            Recommendation first  = rp.getFirst();
-            Recommendation second = rp.getSecond();
-
-            for (Recommendation recommendation: toUse) {
-                if (first != null && first.getIDs().equals(recommendation.getIDs())) {
-                    first = null;
-                }
-                if (second != null && second.getIDs().equals(recommendation.getIDs())) {
-                    second = null;
-                }
-
-                if (first == null && second == null) {
-                    break;
-                }
-            }
-            if (first != null) {
-                artifactIdsToRemove.add(first.getIDs());
-            }
-            if (second != null) {
-                artifactIdsToRemove.add(second.getIDs());
-            }
-        }
-
-        // Remove old artifacts, if any. Do this asychronously without much
-        // feedback.
-        for(final String uuid: artifactIdsToRemove) {
-            removeArtifactService.remove(this.collection,
-                uuid,
-                locale,
-                new AsyncCallback<Collection>() {
-                    @Override
-                    public void onFailure(Throwable caught) {
-                        GWT.log("RemoveArtifact (" + uuid + ") failed.");
-                    }
-                    @Override
-                    public void onSuccess(Collection collection) {
-                        GWT.log("RemoveArtifact succeeded");
-                    }
-                });
-        }
-
-        // Clone new ones (and spawn statics), go forward.
-        parameterList.lockUI();
-        loadArtifactService.loadMany(
-            this.collection,
-            toClone,
-            //"staticwkms" and "waterlevel"
-            null,
-            locale,
-            new AsyncCallback<Artifact[]>() {
-                @Override
-                public void onFailure(Throwable caught) {
-                    GWT.log("Failure of cloning with factories!");
-                    parameterList.unlockUI();
-                }
-                @Override
-                public void onSuccess(Artifact[] artifacts) {
-                    GWT.log("Successfully cloned " + toClone.length +
-                        " with factories.");
-
-                    fireStepForwardEvent(new StepForwardEvent(
-                        getData(toClone, artifacts, toUse)));
-                    parameterList.unlockUI();
-                }
-            });
-    }
-
-
-    /**
-     * Create Data and DataItem from selection (a long string with identifiers
-     * to construct diff-pairs).
-     *
-     * @param newRecommendations "new" recommendations (did not survive a
-     *        backjump).
-     * @param newArtifacts artifacts cloned from newRecommendations.
-     * @param oldRecommendations old recommendations that survived a backjump.
-     *
-     * @return dataitem with a long string with identifiers to construct
-     *         diff-pairs.
-     */
-    protected Data[] getData(
-            Recommendation[] newRecommendations,
-            Artifact[] newArtifacts,
-            Recommendation[] oldRecommendations)
-    {
-        // Construct string with info about selections.
-        String dataItemString = "";
-        for (int i = 0; i < newRecommendations.length; i++) {
-            Recommendation r = newRecommendations[i];
-            Artifact newArtifact = newArtifacts[i];
-            String uuid = newArtifact.getUuid();
-            r.setMasterArtifact(uuid);
-            if (i>0) dataItemString += "#";
-
-            dataItemString += createDataString(uuid, r);
-        }
-
-        for (int i = 0; i < oldRecommendations.length; i++) {
-            Recommendation r = oldRecommendations[i];
-            String uuid = r.getIDs();
-            if (dataItemString.length() > 0) dataItemString += "#";
-
-            dataItemString += createDataString(uuid, r);
-        }
-
-        // TODO some hassle could be resolved by using multiple DataItems
-        // (e.g. one per pair).
-        DataItem item = new DefaultDataItem(dataName, dataName, dataItemString);
-        return new Data[] { new DefaultData(
-            dataName, null, null, new DataItem[] {item}) };
-    }
-
-
-    protected String createDataString(String artifact, Recommendation recommendation) {
-        return createDataString(artifact, recommendation, "staticwkms");
-    }
-
-    /**
-     * Creates part of the String that encodes minuend or subtrahend.
-     * @param artifact Artifacts UUID.
-     * @param recommendation Recommendation to wrap in string.
-     * @param factory The factory to encode.
-     */
-    protected String createDataString(
-        String artifact,
-        Recommendation recommendation,
-        String factory)
-    {
-        Filter filter = recommendation.getFilter();
-        Facet  f      = null;
-
-        if(filter != null) {
-            Map<String, List<Facet>>               outs = filter.getOuts();
-            Set<Map.Entry<String, List<Facet>>> entries = outs.entrySet();
-
-            for (Map.Entry<String, List<Facet>> entry: entries) {
-                List<Facet> fs = entry.getValue();
-
-                f = fs.get(0);
-                if (f != null) {
-                    break;
-                }
-            }
-
-            return "[" + artifact + ";"
-                + f.getName()
-                + ";"
-                + f.getIndex()
-                + ";"
-                + recommendation.getDisplayName() + "]";
-        }
-        else {
-            return "["
-                + artifact
-                + ";" + factory + ";0;"
-                + recommendation.getDisplayName() + "]";
-        }
-    }
-}
-// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :
+}
\ No newline at end of file