io.github.linuxforhealth.hl7.expression.variable.ExpressionVariable Maven / Gradle / Ivy

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

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import io.github.linuxforhealth.api.EvaluationResult;
import io.github.linuxforhealth.api.InputDataExtractor;
import io.github.linuxforhealth.core.expression.EmptyEvaluationResult;

/**
 * Defines Variable object that can be used during the expression evaluation.
 * 
 * 
 * @author pbhallam
 */
public class ExpressionVariable extends SimpleVariable {

    private String expression;

    /**
     * Constructor for Variable with default type: Object
     * 
     * @param name The name of the variable Example: "var1"
     * @param expression The expression to evaluate. Example: "OBX.5 *, GeneralUtils.testFunction(x, y)"
     * @param spec A list of tokens in the expression
     * @param extractMultiple Whether to extract multiple expressions
     */
    public ExpressionVariable(String name, String expression, List spec,
            boolean extractMultiple) {
        super(name, spec, extractMultiple, false);
        this.expression = expression;
    }

    public ExpressionVariable(String name, String expression, List spec,
            boolean extractMultiple, boolean retainEmpty) {
        super(name, spec, extractMultiple, false, retainEmpty);
        this.expression = expression;
    }

    // resolve variable value
    @Override
    public EvaluationResult extractVariableValue(Map contextValues,
            InputDataExtractor dataSource) {
        EvaluationResult result = null;
        if (!this.getSpec().isEmpty()) {
            result = getValueFromSpecs(contextValues, dataSource);
        }
        if (result == null) {
            result = new EmptyEvaluationResult();
        }

        if (this.expression != null) {
            // resolve expression
            Map localContextValues = new HashMap<>(contextValues);

            localContextValues.put(this.getName(), result);

            result = dataSource.evaluateJexlExpression(expression, localContextValues);
        }
        return result;

    }

    /**
     * @return String representation of expression
     */
    public String getExpression() {
        return expression;
    }
}