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package org.gvsig.app.join.dal.feature;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.HashMap;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import java.util.Map.Entry;

import org.gvsig.fmap.dal.exception.DataException;

import org.gvsig.fmap.dal.feature.AbstractFeatureStoreTransform;

import org.gvsig.fmap.dal.feature.EditableFeature;

import org.gvsig.fmap.dal.feature.EditableFeatureAttributeDescriptor;

import org.gvsig.fmap.dal.feature.EditableFeatureType;

import org.gvsig.fmap.dal.feature.Feature;

import org.gvsig.fmap.dal.feature.FeatureAttributeDescriptor;

import org.gvsig.fmap.dal.feature.FeatureQuery;

import org.gvsig.fmap.dal.feature.FeatureSet;

import org.gvsig.fmap.dal.feature.FeatureStore;

import org.gvsig.fmap.dal.feature.FeatureType;

import org.gvsig.tools.ToolsLocator;

import org.gvsig.tools.dispose.DisposableIterator;

import org.gvsig.tools.dynobject.DynStruct;

import org.gvsig.tools.evaluator.Evaluator;

import org.gvsig.tools.evaluator.EvaluatorData;

import org.gvsig.tools.evaluator.EvaluatorException;

import org.gvsig.tools.evaluator.EvaluatorFieldsInfo;

import org.gvsig.tools.persistence.PersistenceManager;

import org.gvsig.tools.persistence.PersistentState;

import org.gvsig.tools.persistence.exception.PersistenceException;

public class JoinTransform extends AbstractFeatureStoreTransform {

    public static final String PERSISTENCE_DEFINITION_NAME = "JoinTransform";

    /**

     * Store from which the join transform will get the additional attributes

     */

    private FeatureStore store2;

    /**

     * name of the key attr in store1 that will be used to match features in

     * store2

     */

    private String keyAttr1;

    /**

     * name of the key attr in store2 that will be used to match features in

     * store1

     */

    private String keyAttr2;

    /**

     * names of the attributes to join from store2 to store1

     */

    private String[] attrs;

    /**

     * Attribute names may change after transformation a prefix is applied.

     * This map keeps correspondence between store1 original names

     * and their transformed counterparts.

     */

    private Map<String,String> store1NamesMap;

    /**

     * Attribute names may change after transformation if they are repeated in

     * both stores or if a prefix is applied. This map keeps correspondence

     * between store2 original names and their transformed counterparts.

     */

    private Map<String,String> store2NamesMap;

    private JoinTransformEvaluator evaluator = null;

    private FeatureType originalFeatureType;

    private String[] attrsForQuery;

    private String prefix1;

    private String prefix2;

    /**

     * A default constructor

     */

    public JoinTransform() {

        store1NamesMap = new HashMap<String,String>();

        store2NamesMap = new HashMap<String,String>();

    }

    /**

     * Initializes all the necessary data for this transform

     *

     * @param store1

     *            store whose default feature type is the target of this

     *            transform

     *

     * @param store2

     *            store whose default feature type will provide the new

     *            attributes to join

     *

     * @param keyAttr1

     *            key attribute in store1 that matches keyAttr2 in store2

     *            (foreign key), used for joining both stores.

     *

     * @param keyAttr2

     *            key attribute in store2 that matches keyAttr1 in store2

     *            (foreign key), used for joining both stores.

     *

     * @param attrs

     *            names of the attributes in store2 that will be joined to

     *            store1.

     */

    public void initialize(FeatureStore store1, FeatureStore store2,

        String keyAttr1, String keyAttr2, String prefix1, String prefix2,

        String[] attrs)

    throws DataException {

        if (store1 == store2) {

            throw new IllegalArgumentException("store1 == store2");

        }

        // Initialize needed data

        this.setFeatureStore(store1);

        this.store2 = store2;

        this.keyAttr1 = keyAttr1;

        this.keyAttr2 = keyAttr2;

        this.prefix1 = prefix1; // TODO

        this.prefix2 = prefix2; // TODO

        this.attrs = attrs;

        // calculate this transform resulting feature type

        // by adding all specified attrs from store2 to store1's default

        // feature type

        // FIXME for more than one FTypes ??

        this.originalFeatureType = this.getFeatureStore()

        .getDefaultFeatureType();

        // keep index of geometry and att desc ==============

        int orig_geom_field_index =

            this.originalFeatureType.getDefaultGeometryAttributeIndex();

        FeatureAttributeDescriptor orig_geom_field_att = 

            this.originalFeatureType.getDefaultGeometryAttribute();

        // Create the feature type and copy the store 1 type        

        EditableFeatureType editableFeatureType = this.getFeatureStore().getDefaultFeatureType().getEditable();

        FeatureAttributeDescriptor[] featureAttributeDescriptors = editableFeatureType.getAttributeDescriptors();

        for (int i=0 ; i<featureAttributeDescriptors.length ; i++){ 

            editableFeatureType.remove(featureAttributeDescriptors[i].getName());           

        }    

        addFeatureType(editableFeatureType, featureAttributeDescriptors, prefix1, store1NamesMap);

        // =========== set the new geom field name and restore geometry values

        if (orig_geom_field_index >= 0) {

            EditableFeatureAttributeDescriptor ed_att = null;

            ed_att = (EditableFeatureAttributeDescriptor)

                editableFeatureType.getAttributeDescriptor(orig_geom_field_index);

            ed_att.setSRS(orig_geom_field_att.getSRS());

            ed_att.setObjectClass(orig_geom_field_att.getObjectClass());

            ed_att.setGeometryType(orig_geom_field_att.getGeomType());

            ed_att.setDefaultValue(orig_geom_field_att.getDefaultValue());

            String new_geom_field_name = ed_att.getName();

            editableFeatureType.setDefaultGeometryAttributeName(new_geom_field_name);

        }

        // =====================================================================

        // Add the store 2 fields    

        FeatureType featureType2 = store2.getDefaultFeatureType();

        // Add the fields       

        for (int i = 0; i < attrs.length; i++) {

            addFeatureType(editableFeatureType, featureType2.getAttributeDescriptor(attrs[i]), prefix2, store2NamesMap);        

        }

        if (this.store2NamesMap.containsKey(keyAttr2)) {

            this.attrsForQuery = this.attrs;

        } else {

            List<String> list = new ArrayList<String>(this.attrs.length + 1);

            list.addAll(Arrays.asList(this.attrs));

            list.add(keyAttr2);

            this.attrsForQuery = (String[]) list.toArray(new String[] {});

        }

        // assign calculated feature type as this transform's feature type

        FeatureType[] types = new FeatureType[] { editableFeatureType.getNotEditableCopy() };

        setFeatureTypes(Arrays.asList(types), types[0]);

    }

    private void addFeatureType(EditableFeatureType targetFeatureType, FeatureAttributeDescriptor[] featureAttributeDescriptors,

        String prefix, Map<String, String> storeMap) throws DataException{

        for (int i=0 ; i<featureAttributeDescriptors.length ; i++){         

            addFeatureType(targetFeatureType, featureAttributeDescriptors[i], prefix, storeMap);

        }

    }

    private void addFeatureType(EditableFeatureType targetFeatureType, FeatureAttributeDescriptor featureAttributeDescriptor,

        String prefix, Map<String, String> storeMap) throws DataException{

        String attName = featureAttributeDescriptor.getName();

        if ((prefix != null) && (!prefix.equals(""))){

            attName = prefix + "_" + attName;

        }

        // If an attribute already exists, calculate an alternate name and add it to our type

        int j = 0;

        while (targetFeatureType.getIndex(attName) >= 0) {

            attName = targetFeatureType.getAttributeDescriptor(attName).getName() + "_" + ++j;

        }

        EditableFeatureAttributeDescriptor editableFeatureAttributeDescriptor = 

            targetFeatureType.add(attName, featureAttributeDescriptor.getType(),

                featureAttributeDescriptor.getSize());

        editableFeatureAttributeDescriptor.setPrecision(featureAttributeDescriptor.getPrecision());

        // keep correspondence between original name and transformed name

        storeMap.put(featureAttributeDescriptor.getName(), attName);

    } 

    /**

     *

     *

     * @param source

     *

     * @param target

     *

     * @throws DataException

     */

    public void applyTransform(Feature source, EditableFeature target)

    throws DataException {

        // copy the data from store1 into the resulting feature

        this.copySourceToTarget(source, target);

        // ask store2 for the specified attributes, filtering by the key

        // attribute value

        // from the source feature

        JoinTransformEvaluator eval = this.getEvaluator();

        eval.updateValue(source.get(this.keyAttr1));

        FeatureQuery query = store2.createFeatureQuery();

        query.setAttributeNames(attrsForQuery);

        query.setFilter(eval);

        FeatureSet set = null;

        DisposableIterator itFeat = null;

        try {

            set = store2.getFeatureSet(query);

            // In this join implementation, we will take only the first matching

            // feature found in store2

            Feature feat;

            itFeat = set.iterator();

            if (itFeat.hasNext()) {

                feat = (Feature) itFeat.next();

                // copy all attributes from joined feature to target

                this.copyJoinToTarget(feat, target);

            }

        } finally {

            if (itFeat != null) {

                itFeat.dispose();

            }

            if (set != null) {

                set.dispose();

            }

        }

    }

    /**

     * @param feat

     * @param target

     */

    private void copyJoinToTarget(Feature join, EditableFeature target) {

        Iterator<Entry<String, String>> iter = store2NamesMap.entrySet()

        .iterator();

        Entry<String, String> entry;

        FeatureType trgType = target.getType();

        FeatureAttributeDescriptor attr;

        while (iter.hasNext()) {

            entry = iter.next();

            attr = trgType.getAttributeDescriptor((String) entry.getValue());

            if (attr != null) {

                target.set(attr.getIndex(), join.get((String) entry.getKey()));

            }

        }

    }

    /**

     * @param source

     * @param target

     */

    private void copySourceToTarget(Feature source, EditableFeature target) {

        FeatureAttributeDescriptor attr, attrTrg;

        FeatureType ftSrc = source.getType();

        FeatureType ftTrg = target.getType();

        for (int i = 0; i < source.getType().size(); i++) {

            attr = ftSrc.getAttributeDescriptor(i);

            attrTrg = ftTrg.getAttributeDescriptor(store1NamesMap.get(attr.getName()));

            if (attrTrg != null) {

                try {

                    target.set(attrTrg.getIndex(), source.get(i));

                } catch (IllegalArgumentException e) {

                    attrTrg = ftTrg.getAttributeDescriptor(attr.getName());

                    target.set(attrTrg.getIndex(), attrTrg.getDefaultValue());

                }

            }

        }

    }

    private JoinTransformEvaluator getEvaluator() {

        if (this.evaluator == null){

            this.evaluator = new JoinTransformEvaluator(keyAttr2);

        }

        return evaluator;

    }

    private class JoinTransformEvaluator implements Evaluator {

        private String attribute;

        private Object value;

        private String sql;

        private EvaluatorFieldsInfo info = null;

        //                private int attributeIndex;

        public JoinTransformEvaluator(String attribute) {

            this.attribute = attribute;

            this.value = null;

            this.info = new EvaluatorFieldsInfo();

            //                        this.attributeIndex = attrIndex;

        }

        public void updateValue(Object value) {

            this.value = value;

            this.sql = this.attribute + "= '" + this.value + "'";

            this.info = new EvaluatorFieldsInfo();

            this.info.addMatchFieldValue(this.attribute, value);

        }

        public Object evaluate(EvaluatorData arg0) throws EvaluatorException {

            Object curValue = arg0.getDataValue(attribute);

            if (curValue == null) {

                return value == null;

            }

            return curValue.equals(value);

        }

        public String getSQL() {

            return this.sql;

        }

        public String getDescription() {

            return "Evaluates join transform match";

        }

        public String getName() {

            return "JoinTransformEvaluator";

        }

        public EvaluatorFieldsInfo getFieldsInfo() {

            return this.info;

        }

    }        

    @SuppressWarnings("unchecked")

    public FeatureType getSourceFeatureTypeFrom(FeatureType arg0) {

        return originalFeatureType;

    }

    public boolean isTransformsOriginalValues() {

        return false;

    }

    public static void registerPersistent() {

        PersistenceManager persistenceManager = ToolsLocator.getPersistenceManager();

        if( persistenceManager.getDefinition(AbstractFeatureStoreTransform.class) == null ) {

            AbstractFeatureStoreTransform.registerPersistent();

        }

        DynStruct definition = persistenceManager.getDefinition(PERSISTENCE_DEFINITION_NAME);

        if (definition == null){  

            definition = persistenceManager.addDefinition(

                JoinTransform.class,

                PERSISTENCE_DEFINITION_NAME,

                "JoinTransform Persistence definition",

                null, 

                null

            );

            definition.extend(PersistenceManager.PERSISTENCE_NAMESPACE,

                ABSTRACT_FEATURESTORE_DYNCLASS_NAME);

            definition.addDynFieldObject("store2").setClassOfValue(FeatureStore.class).setMandatory(true);

            definition.addDynFieldString("keyAttr1").setMandatory(true);

            definition.addDynFieldString("keyAttr2").setMandatory(true);

            definition.addDynFieldString("prefix1").setMandatory(false);

            definition.addDynFieldString("prefix2").setMandatory(false);

            definition.addDynFieldList("attrs").setClassOfItems(String.class).setMandatory(true);

        }

    }

    public void saveToState(PersistentState state) throws PersistenceException {

        super.saveToState(state);

        state.set("store2", this.store2);

        state.set("keyAttr1", this.keyAttr1);

        state.set("keyAttr2", this.keyAttr2);

        state.set("prefix1", this.prefix1);

        state.set("prefix2", this.prefix2);                

        state.set("attrs", this.attrs);

    }

    public void loadFromState(PersistentState state) throws PersistenceException {

        super.loadFromState(state);

        FeatureStore store2 = (FeatureStore) state.get("store2");

        String keyAttr1 = state.getString("keyAttr1");

        String keyAttr2 = state.getString("keyAttr2");

        String prefix2 =  state.getString("prefix2");

        String[] attrs = (String[]) state.getArray("attrs", String.class);

        try {

            initialize(getFeatureStore(), store2, keyAttr1, keyAttr2, prefix1, prefix2, attrs);

        } catch (DataException e) {

            throw new PersistenceException("Impossible to create the transform", e);

        }

    }

}