freemarker.cache.StringTemplateLoader Maven / Gradle / Ivy
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Google App Engine compliant variation of FreeMarker.
FreeMarker is a "template engine"; a generic tool to generate text output based on templates.
/*
* Copyright (c) 2005 The Visigoth Software Society. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowledgement:
* "This product includes software developed by the
* Visigoth Software Society (http://www.visigoths.org/)."
* Alternately, this acknowledgement may appear in the software itself,
* if and wherever such third-party acknowledgements normally appear.
*
* 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the
* project contributors may be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact [email protected].
*
* 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
* nor may "FreeMarker" or "Visigoth" appear in their names
* without prior written permission of the Visigoth Software Society.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Visigoth Software Society. For more
* information on the Visigoth Software Society, please see
* http://www.visigoths.org/
*/
package freemarker.cache;
import java.io.Reader;
import java.io.StringReader;
import java.util.HashMap;
import java.util.Map;
/**
* A {@link TemplateLoader} that uses a Map with Strings as its source of
* templates.
*
* In most case the regular way of loading templates from files will be fine.
* However, there can be situations where you don't want to or can't load a
* template from a file, e.g. if you have to deploy a single jar for
* JavaWebStart or if they are contained within a database.
* A single template can be created manually
* e.g.
*
* String templateStr="Hello ${user}";
* Template t = new Template("name", new StringReader(templateStr),
* new Configuration());
*
* If, however, you want to create templates from strings which import other
* templates this method doesn't work.
*
* In that case you can create a StringTemplateLoader and add each template to
* it:
*
* StringTemplateLoader stringLoader = new StringTemplateLoader();
* stringLoader.putTemplate("greetTemplate", "<#macro greet>Hello");
* stringLoader.putTemplate("myTemplate", "<#include \"greetTemplate\"><@greet/> World!");
*
* Then you tell your Configuration object to use it:
*
* cfg.setTemplateLoader(stringLoader);
*
* After that you should be able to use the templates as usual. Often you will
* want to combine a StringTemplateLoader with another loader. You can
* do so using a {@link freemarker.cache.MultiTemplateLoader}.
*
* @version $Id: v 1.0 2005/04/01
* @author Meikel Bisping
* @author Attila Szegedi
* @version $Id: StringTemplateLoader.java,v 1.1 2005/04/08 11:47:53 szegedia Exp $
*/
public class StringTemplateLoader implements TemplateLoader {
private final Map templates = new HashMap();
/**
* Puts a template into the loader. A call to this method is identical to
* the call to the three-arg {@link #putTemplate(String, String, long)}
* passing System.currentTimeMillis() as the third argument.
* @param name the name of the template.
* @param templateSource the source code of the template.
*/
public void putTemplate(String name, String templateSource) {
putTemplate(name, templateSource, System.currentTimeMillis());
}
/**
* Puts a template into the loader. The name can contain slashes to denote
* logical directory structure, but must not start with a slash. If the
* method is called multiple times for the same name and with different
* last modified time, the configuration's template cache will reload the
* template according to its own refresh settings (note that if the refresh
* is disabled in the template cache, the template will not be reloaded).
* Also, since the cache uses lastModified to trigger reloads, calling the
* method with different source and identical timestamp won't trigger
* reloading.
* @param name the name of the template.
* @param templateSource the source code of the template.
* @param lastModified the time of last modification of the template in
* terms of System.currentTimeMillis()
*/
public void putTemplate(String name, String templateSource, long lastModified) {
templates.put(name, new StringTemplateSource(name, templateSource, lastModified));
}
public void closeTemplateSource(Object templateSource) {
}
public Object findTemplateSource(String name) {
return templates.get(name);
}
public long getLastModified(Object templateSource) {
return ((StringTemplateSource)templateSource).lastModified;
}
public Reader getReader(Object templateSource, String encoding) {
return new StringReader(((StringTemplateSource)templateSource).source);
}
private static class StringTemplateSource {
private final String name;
private final String source;
private final long lastModified;
StringTemplateSource(String name, String source, long lastModified) {
if(name == null) {
throw new IllegalArgumentException("name == null");
}
if(source == null) {
throw new IllegalArgumentException("source == null");
}
if(lastModified < -1L) {
throw new IllegalArgumentException("lastModified < -1L");
}
this.name = name;
this.source = source;
this.lastModified = lastModified;
}
public boolean equals(Object obj) {
if(obj instanceof StringTemplateSource) {
return name.equals(((StringTemplateSource)obj).name);
}
return false;
}
public int hashCode() {
return name.hashCode();
}
}
}