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Implementation of mustache.js for Java
There is a newer version: 0.9.14
package com.github.mustachejava;

import java.io.*;

/**
 * Mustache.java factory with a fallback mechanism for locating resources.
 * 
 * (Some parts are based on DefaultMustacheFactory code that is Copyright 2010 RightTime, Inc.)
 * 
 * @author gw0 [http://gw.tnode.com/] 
 */
public class FallbackMustacheFactory extends DefaultMustacheFactory {
	
	/** List of fallback resource roots to search through. */
	private Object[] resourceRoots;
	
	/** Simple constructor for a fallback Mustache.java factory.
	 * 
	 * @param resourceRoot normal resource root
	 * @param fallbackRoot fallback alternative root
	 */
	public FallbackMustacheFactory(String resourceRoot, String fallbackRoot) {
		this(new String[] {resourceRoot, fallbackRoot});
	}
	
	/** Simple constructor for a fallback Mustache.java factory.
	 * 
	 * @param resourceRoot normal resource root
	 * @param fallbackRoot fallback alternative root
	 */
	public FallbackMustacheFactory(File fileRoot, File fallbackRoot) {
		this(new File[] {fileRoot, fallbackRoot});
	}

	/** Generic constructor for a fallback Mustache.java factory.
	 * 
	 * @param resourceRoots array of fallback resource roots as String or File
	 */
	public FallbackMustacheFactory(Object[] resourceRoots) {
		super();
		
		for(Object resourceObj : resourceRoots) {
			if(resourceObj instanceof String) {  // for String
				String resourceRoot = (String)resourceObj;
				if (!resourceRoot.endsWith("/")) resourceRoot += "/";
				
			} else if(resourceObj instanceof File) {  // for File
				File fileRoot = (File)resourceObj;
				if(!fileRoot.exists()) {
					throw new MustacheException(fileRoot + " does not exist");
				}
				if (!fileRoot.isDirectory()) {
					throw new MustacheException(fileRoot + " is not a directory");
				}
				
			} else if(resourceObj == null) {  // for null
				
			} else {
				throw new MustacheException("Invalid constructor parameter: " + resourceObj.toString());
			}
		}
	    this.resourceRoots = resourceRoots;
	}	
	
	/** Return a reader for accessing resource files.
	 *
	 * @param resourceName resource name relative to one of the fallback resource roots
	 * @return resource file reader
	 */
	@Override
	public Reader getReader(String resourceName) {
		Exception lastException = null;
		
		for(Object resourceObj : this.resourceRoots) {
			try {
				InputStream is = null;
				if(resourceObj instanceof String) {  // class resource loader only for String
					String resourceRoot = (String)resourceObj;
					ClassLoader ccl = Thread.currentThread().getContextClassLoader();
					is = ccl.getResourceAsStream((resourceRoot == null ? "" : resourceRoot) + resourceName);
				}
				
				if (is == null) {
					File file;
					if(resourceObj instanceof String) {  // for String
						file = new File((String)resourceObj, resourceName);
					} else if(resourceObj instanceof File) {  // for File
						file = new File((File)resourceObj, resourceName);
					} else {  // for null
						file = new File(resourceName);
					}
					
					if (file.exists() && file.isFile()) {
						try {
							is = new FileInputStream(file);
						} catch (FileNotFoundException e) {
							throw new MustacheException("Found file, could not open: " + file, e);
						}
					}
				}
				
				if (is == null) {
					throw new MustacheException("Template '" + resourceName + "' not found");
				} else {
					return new BufferedReader(new InputStreamReader(is, "UTF-8"));
				}
				
			} catch(Exception e) {
				lastException = e;
			}
		}
		throw new MustacheException("Template " + resourceName + " not found", lastException);
	}

}