org.springframework.batch.support.PropertiesConverter.java Source code

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Here is the source code for org.springframework.batch.support.PropertiesConverter.java

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/*
 * Copyright 2006-2007 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
 *
 *      https://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.springframework.batch.support;

import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.Arrays;
import java.util.List;
import java.util.Properties;

import org.springframework.util.DefaultPropertiesPersister;
import org.springframework.util.PropertiesPersister;
import org.springframework.util.StringUtils;

/**
 * Utility to convert a Properties object to a String and back. Ideally this
 * utility should have been used to convert to string in order to convert that
 * string back to a Properties Object. Attempting to convert a string obtained
 * by calling Properties.toString() will return an invalid Properties object.
 * The format of Properties is that used by {@link PropertiesPersister} from the
 * Spring Core, so a String in the correct format for a Spring property editor
 * is fine (key=value pairs separated by new lines).
 * 
 * @author Lucas Ward
 * @author Dave Syer
 * 
 * @see PropertiesPersister
 */
public final class PropertiesConverter {

    private static final PropertiesPersister propertiesPersister = new DefaultPropertiesPersister();

    private static final String LINE_SEPARATOR = System.getProperty("line.separator");

    // prevents the class from being instantiated
    private PropertiesConverter() {
    }

    /**
     * Parse a String to a Properties object. If string is null, an empty
     * Properties object will be returned. The input String is a set of
     * name=value pairs, delimited by either newline or comma (for brevity). If
     * the input String contains a newline it is assumed that the separator is
     * newline, otherwise comma.
     * 
     * @param stringToParse String to parse.
     * @return Properties parsed from each string.
     * @see PropertiesPersister
     */
    public static Properties stringToProperties(String stringToParse) {

        if (stringToParse == null) {
            return new Properties();
        }

        if (!contains(stringToParse, "\n")) {
            stringToParse = StringUtils
                    .arrayToDelimitedString(StringUtils.commaDelimitedListToStringArray(stringToParse), "\n");
        }

        StringReader stringReader = new StringReader(stringToParse);

        Properties properties = new Properties();

        try {
            propertiesPersister.load(properties, stringReader);
            // Exception is only thrown by StringReader after it is closed,
            // so never in this case.
        } catch (IOException ex) {
            throw new IllegalStateException(
                    "Error while trying to parse String to java.util.Properties," + " given String: " + properties);
        }

        return properties;
    }

    /**
     * Convert Properties object to String. This is only necessary for
     * compatibility with converting the String back to a properties object. If
     * an empty properties object is passed in, a blank string is returned,
     * otherwise it's string representation is returned.
     * 
     * @param propertiesToParse contains the properties be converted.
     * @return String representation of properties object
     */
    public static String propertiesToString(Properties propertiesToParse) {

        // If properties is empty, return a blank string.
        if (propertiesToParse == null || propertiesToParse.size() == 0) {
            return "";
        }

        StringWriter stringWriter = new StringWriter();

        try {
            propertiesPersister.store(propertiesToParse, stringWriter, null);
        } catch (IOException ex) {
            // Exception is never thrown by StringWriter
            throw new IllegalStateException("Error while trying to convert properties to string");
        }

        // If the value is short enough (and doesn't contain commas), convert to
        // comma-separated...
        String value = stringWriter.toString();
        if (value.length() < 160) {
            List<String> list = Arrays
                    .asList(StringUtils.delimitedListToStringArray(value, LINE_SEPARATOR, LINE_SEPARATOR));
            String shortValue = StringUtils.collectionToCommaDelimitedString(list.subList(1, list.size()));
            int count = StringUtils.countOccurrencesOf(shortValue, ",");
            if (count == list.size() - 2) {
                value = shortValue;
            }
            if (value.endsWith(",")) {
                value = value.substring(0, value.length() - 1);
            }
        }
        return value;
    }

    private static boolean contains(String str, String searchStr) {
        return str.indexOf(searchStr) != -1;
    }
}