package no.uio.ifi.refaktor.utils;

import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.dom.ASTParser;
import org.eclipse.jdt.core.dom.CompilationUnit;

public enum CompilationUnitCacheManager {
	INSTANCE;

	private CompilationUnitCache cache = new CompilationUnitNullCache();

	public static CompilationUnit getParsedCompilationUnitFor(ICompilationUnit unit) {
		return INSTANCE.getCompilationUnitFor(unit);
	}

	private CompilationUnit getCompilationUnitFor(ICompilationUnit unit) {
		if (cache.contains(unit))
			return cache.get(unit);

		return parse(unit);
	}

	private CompilationUnit parse(ICompilationUnit unit) {
		ASTParser parser = ParseUtils.createParser();
		parser.setSource(unit);
		CompilationUnit concreteCompilationUnit = (CompilationUnit) parser.createAST(null);
		cache.add(unit, concreteCompilationUnit);
		return concreteCompilationUnit;
	}

	public static void activateHashCaching() {
		INSTANCE.cache = new CompilationUnitHashCache();
	}
	
	public static void activateRecentlyUsedCaching() {
		INSTANCE.cache = new CompilationUnitRecentlyUsedCache();
	}

	public static void deactivateCaching() {
		INSTANCE.cache = new CompilationUnitNullCache();
	}
}