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SchemaCrawler is an open-source Java API that makes working with database metadata as easy as working with plain old Java objects. SchemaCrawler is also a database schema discovery and comprehension, and schema documentation tool. You can search for database schema objects using regular expressions, and output the schema and data in a readable text format. The output is designed to be diff-ed against other database schemas.
/*
*
* SchemaCrawler
* http://sourceforge.net/projects/schemacrawler
* Copyright (c) 2000-2014, Sualeh Fatehi.
*
* This library is free software; you can redistribute it and/or modify it under the terms
* of the GNU Lesser General Public License as published by the Free Software Foundation;
* either version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
*/
package sf.util;
import static sf.util.Utility.isBlank;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;
import java.util.Set;
/**
* Configuration properties.
*
* @author Sualeh Fatehi
*/
public final class TemplatingUtility
{
/**
* Expands a template using system properties. Variables in the
* template are in the form of ${variable}.
*
* @param template
* Template to expand.
* @return Expanded template
*/
public static String expandTemplate(final String template)
{
return expandTemplate(template, propertiesMap(System.getProperties()));
}
/**
* Expands a template using variable values in the provided map.
* Variables in the template are in the form of ${variable}.
*
* @param template
* Template to expand.
* @param variablesMap
* Variables and values.
* @return Expanded template
*/
public static String expandTemplate(final String template,
final Map variablesMap)
{
if (isBlank(template) || variablesMap == null)
{
return template;
}
final StringBuilder buffer = new StringBuilder();
int currentPosition = 0;
int delimiterStartPosition;
int delimiterEndPosition;
while (true)
{
delimiterStartPosition = template.indexOf(DELIMITER_START,
currentPosition);
if (delimiterStartPosition == -1)
{
if (currentPosition == 0)
{
// No substitutions required at all
return template;
}
else
{
// No more substitutions
buffer.append(template.substring(currentPosition, template.length()));
return buffer.toString();
}
}
else
{
buffer.append(template.substring(currentPosition,
delimiterStartPosition));
delimiterEndPosition = template.indexOf(DELIMITER_END,
delimiterStartPosition);
if (delimiterEndPosition > -1)
{
delimiterStartPosition = delimiterStartPosition
+ DELIMITER_START.length();
final String key = template.substring(delimiterStartPosition,
delimiterEndPosition);
final String value = variablesMap.get(key);
if (value != null)
{
buffer.append(value);
}
else
{
// Do not substitute
buffer.append(DELIMITER_START).append(key).append(DELIMITER_END);
}
// Advance current position
currentPosition = delimiterEndPosition + DELIMITER_END.length();
}
else
{
// End brace not found, so advance current position
buffer.append(DELIMITER_START);
currentPosition = delimiterStartPosition + DELIMITER_START.length();
}
}
}
}
/**
* Extracts variables from the template. Variables are in the form of
* ${variable}.
*
* @param template
* Template to extract variables from.
* @return Extracted variables
*/
public static Set extractTemplateVariables(final String template)
{
if (Utility.isBlank(template))
{
return new HashSet<>();
}
String shrunkTemplate = template;
final Set keys = new HashSet<>();
for (int left; (left = shrunkTemplate.indexOf(DELIMITER_START)) >= 0;)
{
final int right = shrunkTemplate.indexOf(DELIMITER_END, left + 2);
if (right >= 0)
{
final String propertyKey = shrunkTemplate.substring(left + 2, right);
keys.add(propertyKey);
// Destroy key, so we can find the next one
shrunkTemplate = shrunkTemplate.substring(0, left)
+ shrunkTemplate.substring(right + 1);
}
else
{
// No ending baracket found
break;
}
}
return keys;
}
/**
* Does one pass over the values in the map, and expands each as a
* template, using the rest of the values in the same map. Variables
* in the template are in the form of ${variable}.
*
* @param variablesMap
* Map to expand.
*/
public static void substituteVariables(final Map variablesMap)
{
if (variablesMap != null && !variablesMap.isEmpty())
{
for (final Map.Entry entry: variablesMap.entrySet())
{
variablesMap.put(entry.getKey(),
expandTemplate(entry.getValue(), variablesMap));
}
}
}
/**
* Copies properties into a map.
*
* @param properties
* Properties to copy
* @return Map of properties and values
*/
private static Map propertiesMap(final Properties properties)
{
final Map propertiesMap = new HashMap<>();
if (properties != null)
{
final Set> entries = properties.entrySet();
for (final Entry entry: entries)
{
propertiesMap.put((String) entry.getKey(), (String) entry.getValue());
}
}
return propertiesMap;
}
private static final String DELIMITER_START = "${";
private static final String DELIMITER_END = "}";
private TemplatingUtility()
{
}
}