ConvertLoopFix.java

/*******************************************************************************
 * Copyright (c) 2005, 2011 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
/**
 *
 **/
package org.eclipse.jdt.internal.corext.fix;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Hashtable;
import java.util.List;

import org.eclipse.core.runtime.IStatus;

import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.dom.ForStatement;

import org.eclipse.jdt.internal.corext.dom.GenericVisitor;
import org.eclipse.jdt.internal.corext.util.JavaModelUtil;

import org.eclipse.jdt.ui.cleanup.ICleanUpFix;

public class ConvertLoopFix extends CompilationUnitRewriteOperationsFix {

	private final static class ControlStatementFinder extends GenericVisitor {

		private final List<ConvertLoopOperation> fResult;
		private final Hashtable<ForStatement, String> fUsedNames;
		private final boolean fFindForLoopsToConvert;
		private final boolean fConvertIterableForLoops;
		private final boolean fMakeFinal;

		public ControlStatementFinder(boolean findForLoopsToConvert, boolean convertIterableForLoops, boolean makeFinal, List<ConvertLoopOperation> resultingCollection) {
			fFindForLoopsToConvert= findForLoopsToConvert;
			fConvertIterableForLoops= convertIterableForLoops;
			fMakeFinal= makeFinal;
			fResult= resultingCollection;
			fUsedNames= new Hashtable<ForStatement, String>();
		}

		/* (non-Javadoc)
		 * @see org.eclipse.jdt.internal.corext.dom.GenericVisitor#visit(org.eclipse.jdt.core.dom.ForStatement)
		 */
		@Override
		public boolean visit(ForStatement node) {
			if (fFindForLoopsToConvert || fConvertIterableForLoops) {
				ForStatement current= node;
				ConvertLoopOperation operation= getConvertOperation(current);
				ConvertLoopOperation oldOperation= null;
				while (operation != null) {
					if (oldOperation == null) {
						fResult.add(operation);
					} else {
						oldOperation.setBodyConverter(operation);
					}

					if (current.getBody() instanceof ForStatement) {
						current= (ForStatement)current.getBody();
						oldOperation= operation;
						operation= getConvertOperation(current);
					} else {
						operation= null;
					}
				}
				current.getBody().accept(this);
				return false;
			}

			return super.visit(node);
		}

		private ConvertLoopOperation getConvertOperation(ForStatement node) {

			Collection<String> usedNamesCollection= fUsedNames.values();
			String[] usedNames= usedNamesCollection.toArray(new String[usedNamesCollection.size()]);
			ConvertLoopOperation convertForLoopOperation= new ConvertForLoopOperation(node, usedNames, fMakeFinal);
			if (convertForLoopOperation.satisfiesPreconditions().isOK()) {
				if (fFindForLoopsToConvert) {
					fUsedNames.put(node, convertForLoopOperation.getIntroducedVariableName());
					return convertForLoopOperation;
				}
			} else if (fConvertIterableForLoops) {
				ConvertLoopOperation iterableConverter= new ConvertIterableLoopOperation(node, usedNames, fMakeFinal);
				if (iterableConverter.satisfiesPreconditions().isOK()) {
					fUsedNames.put(node, iterableConverter.getIntroducedVariableName());
					return iterableConverter;
				}
			}

			return null;
		}

		/* (non-Javadoc)
		 * @see org.eclipse.jdt.internal.corext.dom.GenericVisitor#endVisit(org.eclipse.jdt.core.dom.ForStatement)
		 */
		@Override
		public void endVisit(ForStatement node) {
			if (fFindForLoopsToConvert || fConvertIterableForLoops) {
				fUsedNames.remove(node);
			}
			super.endVisit(node);
		}

	}

	public static ICleanUpFix createCleanUp(CompilationUnit compilationUnit, boolean convertForLoops, boolean convertIterableForLoops, boolean makeFinal) {
		if (!JavaModelUtil.is50OrHigher(compilationUnit.getJavaElement().getJavaProject()))
			return null;

		if (!convertForLoops && !convertIterableForLoops)
			return null;

		List<ConvertLoopOperation> operations= new ArrayList<ConvertLoopOperation>();
		ControlStatementFinder finder= new ControlStatementFinder(convertForLoops, convertIterableForLoops, makeFinal, operations);
		compilationUnit.accept(finder);

		if (operations.isEmpty())
			return null;

		CompilationUnitRewriteOperation[] ops= operations.toArray(new CompilationUnitRewriteOperation[operations.size()]);
		return new ConvertLoopFix(FixMessages.ControlStatementsFix_change_name, compilationUnit, ops, null);
	}

	public static ConvertLoopFix createConvertForLoopToEnhancedFix(CompilationUnit compilationUnit, ForStatement loop) {
		ConvertLoopOperation convertForLoopOperation= new ConvertForLoopOperation(loop);
		if (!convertForLoopOperation.satisfiesPreconditions().isOK())
			return null;

		return new ConvertLoopFix(FixMessages.Java50Fix_ConvertToEnhancedForLoop_description, compilationUnit, new CompilationUnitRewriteOperation[] {convertForLoopOperation}, null);
	}

	public static ConvertLoopFix createConvertIterableLoopToEnhancedFix(CompilationUnit compilationUnit, ForStatement loop) {
		ConvertIterableLoopOperation loopConverter= new ConvertIterableLoopOperation(loop);
		IStatus status= loopConverter.satisfiesPreconditions();
		if (status.getSeverity() == IStatus.ERROR)
			return null;

		return new ConvertLoopFix(FixMessages.Java50Fix_ConvertToEnhancedForLoop_description, compilationUnit, new CompilationUnitRewriteOperation[] {loopConverter}, status);
	}

	private final IStatus fStatus;

	protected ConvertLoopFix(String name, CompilationUnit compilationUnit, CompilationUnitRewriteOperation[] fixRewriteOperations, IStatus status) {
		super(name, compilationUnit, fixRewriteOperations);
		fStatus= status;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public IStatus getStatus() {
		return fStatus;
	}

}