panda.tpl.ftl.StringTemplateLoader Maven / Gradle / Ivy

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package panda.tpl.ftl;

import java.io.Reader;
import java.io.StringReader;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import freemarker.cache.TemplateLoader;

/**
 * string template loader
 */
public class StringTemplateLoader implements TemplateLoader {
	private Map templates = newTemplates();

	/**
	 * @return the templates
	 */
	protected Map getTemplates() {
		return templates;
	}

	/**
	 * @param templates the templates to set
	 */
	protected void setTemplates(Map templates) {
		this.templates = templates;
	}

	protected Map newTemplates() {
		return new ConcurrentHashMap();
	}
	
	/**
	 * 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) {
		if (templateSource == null) {
			templates.remove(name);
		}
		else {
			templates.put(name, new StringTemplateSource(name, templateSource, lastModified));
		}
	}

	/**
	 * @see freemarker.cache.TemplateLoader#closeTemplateSource(java.lang.Object)
	 */
	public void closeTemplateSource(Object templateSource) {
	}

	/**
	 * @see freemarker.cache.TemplateLoader#findTemplateSource(java.lang.String)
	 */
	public Object findTemplateSource(String name) {
		return templates.get(name);
	}

	/**
	 * @see freemarker.cache.TemplateLoader#getLastModified(java.lang.Object)
	 */
	public long getLastModified(Object templateSource) {
		return ((StringTemplateSource)templateSource).lastModified;
	}

	/**
	 * @see freemarker.cache.TemplateLoader#getReader(java.lang.Object, java.lang.String)
	 */
	public Reader getReader(Object templateSource, String encoding) {
		return new StringReader(((StringTemplateSource)templateSource).source);
	}

	protected static class StringTemplateSource {
		private final String name;
		private final String source;
		private final long lastModified;

		public 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();
		}
	}
}