Renaming SmartTextSelection to DocumentTextSelection.

[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.changers.ExtractAndMoveMethodChanger;
import no.uio.ifi.refaktor.extractors.collectors.PrefixesCollector;
import no.uio.ifi.refaktor.extractors.collectors.PropertyCollector;
import no.uio.ifi.refaktor.extractors.collectors.UnfixesCollector;
import no.uio.ifi.refaktor.prefix.PrefixSet;
import no.uio.ifi.refaktor.utils.DocumentTextSelection;

import org.eclipse.jdt.core.ICompilationUnit;

/**
 * A property extractor that collects all the expression prefixes within a selection
 * (see {@link PrefixesCollector}) that forms the base for calculating the
 * candidates for the move refactoring, and also the unfixes 
 * that are non-candidates for the move refactoring. 
 * 
 * The set of prefixes that are not enclosing any unfixes is put in the set of safe prefixes.
 * This set is used by an Extract and Move Method refactoring to find a suitable target
 * for the Move Method. 
 * 
 * The class is typically used by the {@link ExtractAndMoveMethodChanger}.
 */
public class ExtractAndMoveMethodPrefixesExtractor extends PropertyExtractor {

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

	public ExtractAndMoveMethodPrefixesExtractor(DocumentTextSelection selection, ICompilationUnit icu) {
		super(selection, icu);
		prefixesCollector = new PrefixesCollector(selection);
		unfixesCollector = new UnfixesCollector(selection);
	}

	@Override
	protected void registerCollectors(List<PropertyCollector> collectors) {
		collectors.add(prefixesCollector);
		collectors.add(unfixesCollector);
	}
	
	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();
	}
	
	protected PrefixSet getPrefixes() {
		return prefixesCollector.getPrefixes();
	}

	protected PrefixSet getUnfixes() {
		return unfixesCollector.getUnfixes();
	}
}