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FHIR converter is a Java based library that enables converting Hl7v2 messages to FHIR resources

There is a newer version: 1.0.19

/*
 * (C) Copyright IBM Corp. 2020, 2021
 *
 * SPDX-License-Identifier: Apache-2.0
 */
package io.github.linuxforhealth.hl7.expression;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Preconditions;

import io.github.linuxforhealth.api.EvaluationResult;
import io.github.linuxforhealth.api.Expression;
import io.github.linuxforhealth.api.InputDataExtractor;
import io.github.linuxforhealth.core.expression.EvaluationResultFactory;
import io.github.linuxforhealth.hl7.resource.ResourceEvaluationResult;
import io.github.linuxforhealth.hl7.resource.deserializer.HL7DataBasedResourceDeserializer;
import io.github.linuxforhealth.hl7.util.ExpressionUtility;

/**
 * Represent a expression that represents resolving a json template
 * 
 *
 * @author {user}
 */

public class NestedExpression extends AbstractExpression {
  private static final Logger LOGGER = LoggerFactory.getLogger(NestedExpression.class);

  private Map childexpressions;
  private boolean generateMap;

  public NestedExpression(ExpressionAttributes attr) {
    super(attr);
    this.childexpressions = new HashMap<>();
    if (attr.getExpressions() != null) {
      int index = 0;
      for (ExpressionAttributes nestedattrs : attr.getExpressions()) {
        Expression e = HL7DataBasedResourceDeserializer.generateExpression(nestedattrs);
        if (e != null) {
          this.childexpressions.put("key" + index, e);
          index++;
        }
      }

      this.generateMap = false;
    } else if (attr.getExpressionsMap() != null) {

      for (Entry nestedattrs : attr.getExpressionsMap().entrySet()) {
        Expression e = HL7DataBasedResourceDeserializer.generateExpression(nestedattrs.getValue());
        if (e != null) {
          this.childexpressions.put(nestedattrs.getKey(), e);

        }
      }
      this.generateMap = true;
    }
    Preconditions.checkState(!childexpressions.isEmpty(),
        "childexpressions cannot be null or empty");
  }

  @Override
  protected EvaluationResult evaluateExpression(InputDataExtractor dataSource,
      Map contextValues, EvaluationResult baseValue) {
    LOGGER.info("Evalutating expression");
    
    ResourceEvaluationResult result = ExpressionUtility.evaluate(dataSource, contextValues, baseValue,
        this.childexpressions);
	if (result == null || result.getResolveValues() == null || result.getResolveValues().isEmpty()) {
      return EvaluationResultFactory.getEvaluationResult(null);
    } else {
      if (this.generateMap) {
        return EvaluationResultFactory.getEvaluationResult(result.getResolveValues(),
            result.getAdditionalResolveValues());
      } else {
        List