com.surveypanel.utils.PlaceHolderParser.java Source code

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Here is the source code for com.surveypanel.utils.PlaceHolderParser.java

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/*
 * Copyright 2002-2005 the original author or authors.
 *
 * 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.
 * 
 * Portion of code taken from :
 * org.springframework.beans.factory.config.PropertyPlaceholderConfigurer
 */

package com.surveypanel.utils;

import java.util.HashSet;
import java.util.Set;

import org.apache.log4j.Logger;
import org.springframework.util.StringUtils;

import com.surveypanel.form.Form;
import com.surveypanel.form.QuestionImpl;

public class PlaceHolderParser {

    private static Logger logger = Logger.getLogger(PlaceHolderParser.class);
    public static final String DEFAULT_PLACEHOLDER_PREFIX = "$(";
    public static final String DEFAULT_PLACEHOLDER_SUFFIX = ")";

    public static String parseStringValue(Form form, String strVal) {
        return parseStringValue(form, strVal, new HashSet<String>());
    }

    protected static String parseStringValue(Form form, String strVal, Set<String> visitedPlaceholders) {

        StringBuilder buf = new StringBuilder(strVal);

        int startIndex = strVal.indexOf(DEFAULT_PLACEHOLDER_PREFIX);
        while (startIndex != -1) {
            int endIndex = findPlaceholderEndIndex(buf, startIndex);
            if (endIndex != -1) {
                String placeholder = buf.substring(startIndex + DEFAULT_PLACEHOLDER_PREFIX.length(), endIndex);
                if (!visitedPlaceholders.add(placeholder)) {
                    logger.error("Circular placeholder reference '" + placeholder + "' in property definitions");
                    return placeholder;
                }
                // Recursive invocation, parsing placeholders contained in the
                // placeholder key.
                placeholder = parseStringValue(form, placeholder, visitedPlaceholders);
                // Now obtain the value for the fully resolved key...
                String propVal = resolvePlaceholder(form, placeholder);
                if (propVal != null) {
                    // Recursive invocation, parsing placeholders contained in
                    // the
                    // previously resolved placeholder value.
                    propVal = parseStringValue(form, propVal, visitedPlaceholders);
                    buf.replace(startIndex, endIndex + DEFAULT_PLACEHOLDER_SUFFIX.length(), propVal);
                    if (logger.isTraceEnabled()) {
                        logger.trace("Resolved placeholder '" + placeholder + "'");
                    }
                    startIndex = buf.indexOf(DEFAULT_PLACEHOLDER_PREFIX, startIndex + propVal.length());
                } else {
                    // Proceed with unprocessed value.
                    startIndex = buf.indexOf(DEFAULT_PLACEHOLDER_PREFIX,
                            endIndex + DEFAULT_PLACEHOLDER_SUFFIX.length());
                }
                visitedPlaceholders.remove(placeholder);
            } else {
                startIndex = -1;
            }
        }

        return buf.toString();
    }

    private static int findPlaceholderEndIndex(CharSequence buf, int startIndex) {
        int index = startIndex + DEFAULT_PLACEHOLDER_PREFIX.length();
        int withinNestedPlaceholder = 0;
        while (index < buf.length()) {
            if (StringUtils.substringMatch(buf, index, DEFAULT_PLACEHOLDER_SUFFIX)) {
                if (withinNestedPlaceholder > 0) {
                    withinNestedPlaceholder--;
                    index = index + DEFAULT_PLACEHOLDER_SUFFIX.length();
                } else {
                    return index;
                }
            } else if (StringUtils.substringMatch(buf, index, DEFAULT_PLACEHOLDER_PREFIX)) {
                withinNestedPlaceholder++;
                index = index + DEFAULT_PLACEHOLDER_PREFIX.length();
            } else {
                index++;
            }
        }
        return -1;
    }

    protected static String resolvePlaceholder(Form form, String placeholder) {
        String questionId = placeholder;
        String[] split = questionId.split("_");
        if (split.length == 1) {
            QuestionImpl question = form.getQuestion(questionId);
            Object value = form.get(questionId, form);
            if (question != null && value != null) {
                return form.getText(question.getName() + "_" + question.getAnswerNameByValue(value.toString()));
            }
        } else {
            return form.getText(questionId);
        }
        return "";
    }

}