ComplexCompileExample.java

package hr.hrg.javawatcher;

import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Collection;
import java.util.HashSet;

/**<p>
 *  More complex example showing :
 *  <ul>
 *  	<li>how to compile sass file on change
 *  	<li>how to compile all main files when an include file changes.
 *  	<li>how to know the difference when source or include was changed
 *  	<li>how to avoid redundant compilation when burst change occurs <br>
 *  		<i>(some editors might triger more than one change event in few miliseconds time)</i>
 *  </ul>
 * </p><p>
 *  The compilation step is omitted to make it simple to understand
 *  what this library does.
 *  </p>
 *  
 * */
public class ComplexCompileExample {

	public static void main(String[] args) {

		// tweak this depending how responsive you want to be, but to still catch some duplicate changes
		long burstDelay = 20;

		// for collecting files to compile, and to skip duplicates
		HashSet<Path> todo = new HashSet<>();
		
		// GlobWatcher implements AutoCloseable. Use it in try-with-resources or call .close() manually 
		try( GlobWatcher watcher = new GlobWatcher(Paths.get("./scss"), true) ){
		
			// "**.scss" matches in all folders and subfolders
			watcher.includes("**.scss");
	
			// create matcher on current folder without checking sub-folders for the source scss
			FileMatchGlob sourceFiles = new FileMatchGlob(Paths.get("./"), false);
			// if we do not define rules, then any file found will be accepted
			// match any .scss file in root folder only
			sourceFiles.includes("*.scss");
			
			// add the additional matcher to listen for changes too
			watcher.add(sourceFiles);
			
			//start watching, no configuration should happen after this as it wil give unexpected results
			watcher.init(true);
			
			Collection<FileChangeEntry<FileMatchGlob>> changedFiles = null;
			
			while(!Thread.interrupted()){
	
				changedFiles = watcher.takeBatch(burstDelay);
				if(changedFiles == null) break; // interrupted
				
				for (FileChangeEntry<FileMatchGlob> changed : changedFiles) {	
					if(changed.getMatcher() == sourceFiles){
						// a source file changed, add only it for recompilation
						todo.add(changed.getPath());						
					}else{
						// if any file in include folder changes, we want to recompile all source scss files
						todo.addAll(sourceFiles.getMatched());						
					}
				}
				
				for(Path path: todo){
					compileSass(path);
				}
			}
		}
	}

	static void compileSass(Path sassFile){
		System.out.println("compile: "+sassFile);
		// implement compilation here
	}
}