com.glaf.core.el.ExpressionTools.java Source code

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Here is the source code for com.glaf.core.el.ExpressionTools.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 com.glaf.core.el;

import java.util.Map;

import org.apache.commons.lang3.StringUtils;

import com.glaf.core.util.StringTools;

public class ExpressionTools {

    public static String evaluate(String expression, Map<String, Object> params) {
        if (expression == null || params == null) {
            return expression;
        }
        expression = StringTools.replaceIgnoreCase(expression, "${", "#{");
        StringBuffer sb = new StringBuffer(expression.length() + 1000);
        int begin = 0;
        int end = 0;
        boolean flag = false;
        for (int i = 0; i < expression.length(); i++) {
            if (expression.charAt(i) == '#' && expression.charAt(i + 1) == '{') {
                sb.append(expression.substring(end, i));
                begin = i + 2;
                flag = true;
            }
            if (flag && expression.charAt(i) == '}') {
                String temp = expression.substring(begin, i);
                String value = null;
                try {
                    Object object = Mvel2ExpressionEvaluator.evaluate(temp, params);
                    if (object != null) {
                        value = object.toString();
                    }
                } catch (Exception ex) {
                    // ex.printStackTrace();
                }
                if (StringUtils.isNotEmpty(value)) {
                    sb.append(value);
                    end = i + 1;
                    flag = false;
                } else {
                    sb.append("");
                    end = i + 1;
                    flag = false;
                }
            }
            if (i == expression.length() - 1) {
                sb.append(expression.substring(end, i + 1));
            }
        }
        return sb.toString();
    }

}