Separating the logic of extractors into collectors. ++

[ifi-stolz-refaktor.git] / software / no.uio.ifi.refaktor / src / no / uio / ifi / refaktor / extractors / ExtractAndMoveMethodPrefixesExtractor.java

package no.uio.ifi.refaktor.extractors;

import java.util.List;

import no.uio.ifi.refaktor.utils.SmartTextSelection;

import org.eclipse.jdt.core.ICompilationUnit;
import org.eclipse.jdt.core.dom.ASTVisitor;

/**
 * A property extractor that extracts both the union of expression prefixes 
 * (see {@link UnionOfLongestCommonPrefixesExtractor}), but also the unfixes 
 * that are not candidates for a move refactoring. It is responsible for 
 * calculating the safe targets of an Extract and Move Method refactoring
 * on the base of this knowledge.
 */
public class ExtractAndMoveMethodPrefixesExtractor extends PropertyExtractor {

	private PrefixesCollector prefixesCollector;
	private UnfixesCollector unfixesCollector;
	private PrefixSet safePrefixes = null;

	public ExtractAndMoveMethodPrefixesExtractor(SmartTextSelection selection, ICompilationUnit icu) {
		super(selection, icu);
		prefixesCollector = new PrefixesCollector(selection);
		unfixesCollector = new UnfixesCollector(selection);
	}
	
	public PrefixSet getSafePrefixes() {
		if (safePrefixes == null) {
			safePrefixes = createSafePrefixes();
		}
		return safePrefixes;
	}

	private PrefixSet createSafePrefixes() {
		return prefixesCollector.getPrefixes().minusEnclosedPrefixesFrom(unfixesCollector.getUnfixes());
	}

	public boolean hasUsefulResults() {
		return !getSafePrefixes().isEmpty();
	}

	@Override
	protected void registerVisitors(List<ASTVisitor> visitors) {
		visitors.add(prefixesCollector);
		visitors.add(unfixesCollector);
	}
}