org.flowable.dmn.engine.impl.el.ELConditionExpressionPreParser.java Source code

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Here is the source code for org.flowable.dmn.engine.impl.el.ELConditionExpressionPreParser.java

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/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.flowable.dmn.engine.impl.el;

import org.apache.commons.lang3.StringUtils;

/**
 * @author Yvo Swillens
 */
public class ELConditionExpressionPreParser {

    protected static String[] OPERATORS = new String[] { "==", "!=", "<", ">", ">=", "<=" };

    public static String parse(String expression, String inputVariable, String inputVariableType) {

        expression = expression.replaceAll("fn_date", "date:toDate");
        expression = expression.replaceAll("fn_subtractDate", "date:subtractDate");
        expression = expression.replaceAll("fn_addDate", "date:addDate");
        expression = expression.replaceAll("fn_now", "date:now");

        if (expression.startsWith("#{") || expression.startsWith("${")) {
            return expression;
        }

        StringBuilder parsedExpressionBuilder = new StringBuilder();
        parsedExpressionBuilder.append("#{").append(inputVariable);
        if ("date".equals(inputVariableType) || "number".equals(inputVariableType)) {
            parsedExpressionBuilder.append(parseSegmentWithOperator(expression));
        } else {
            if (expression.startsWith(".")) {
                parsedExpressionBuilder.append(expression);
            } else {
                parsedExpressionBuilder.append(parseSegmentWithOperator(expression));
            }
        }
        parsedExpressionBuilder.append("}");

        return parsedExpressionBuilder.toString();
    }

    protected static String parseSegmentWithOperator(String expression) {
        String parsedExpressionSegment;
        if (expression.length() < 2 || !StringUtils.startsWithAny(expression, OPERATORS)) {
            parsedExpressionSegment = " == " + expression;
        } else {
            parsedExpressionSegment = " " + expression;
        }

        return parsedExpressionSegment;
    }
}