org.hcjf.layers.query.functions.ReferenceFunctionLayer Maven / Gradle / Ivy

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package org.hcjf.layers.query.functions;

import org.hcjf.errors.HCJFRuntimeException;
import org.hcjf.layers.query.ParameterizedQuery;
import org.hcjf.layers.query.Query;
import org.hcjf.properties.SystemProperties;

import java.util.Collection;
import java.util.List;

/**
 * This function resolve the reference using like parameter one o more UUID
 * and returns a joinable map instance for each reference.
 * @author javaito
 */
public class ReferenceFunctionLayer extends BaseQueryFunctionLayer implements QueryFunctionLayerInterface {

    private static final String QUERY = "SELECT * FROM %s WHERE %s IN ?";

    public ReferenceFunctionLayer() {
        super(SystemProperties.get(SystemProperties.Query.Function.REFERENCE_FUNCTION_NAME));
    }

    /**
     * This method resolves the reference of uuid instances and return the joinable map
     * that correspond to the reference object.
     * @param functionName Function name.
     * @param parameters Function's parameters.
     * @return Collection or single instance of joinable map.
     */
    @Override
    public Object evaluate(String functionName, Object... parameters) {
        Object result;
        String resourceName = getParameter(0, parameters);
        String referenceField = "id";
        Object param;

        if(parameters.length >= 3) {
            referenceField = getParameter(1, parameters);
            param = getParameter(2, parameters);
        } else {
            param = getParameter(1, parameters);
        }

        ParameterizedQuery parameterizedQuery = Query.compile(String.format(QUERY, resourceName, referenceField)).getParameterizedQuery();
        if(param != null) {
            if (param instanceof Collection) {
                parameterizedQuery.add(param);
                result = Query.evaluate(parameterizedQuery);
            } else {
                parameterizedQuery.add(List.of(param));
                Collection collection = Query.evaluate(parameterizedQuery);
                if(collection.size() == 1) {
                    result = collection.stream().findFirst().get();
                } else {
                    result = null;
                }
            }
        } else {
            result = null;
        }
        return result;
    }
}