LambdaExpressionsCleanUp.java

/*******************************************************************************
 * Copyright (c) 2013 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.ui.fix;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.eclipse.core.runtime.CoreException;

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

import org.eclipse.jdt.internal.corext.fix.CleanUpConstants;
import org.eclipse.jdt.internal.corext.fix.LambdaExpressionsFix;

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

public class LambdaExpressionsCleanUp extends AbstractCleanUp {

	public LambdaExpressionsCleanUp(Map<String, String> options) {
		super(options);
	}

	public LambdaExpressionsCleanUp() {
		super();
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public CleanUpRequirements getRequirements() {
		return new CleanUpRequirements(requireAST(), false, false, null);
	}

	private boolean requireAST() {
		boolean convertFunctionalInterfaces= isEnabled(CleanUpConstants.CONVERT_FUNCTIONAL_INTERFACES);
		if (!convertFunctionalInterfaces)
			return false;
		
		return isEnabled(CleanUpConstants.USE_LAMBDA)
				|| isEnabled(CleanUpConstants.USE_ANONYMOUS_CLASS_CREATION);
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public ICleanUpFix createFix(CleanUpContext context) throws CoreException {
		CompilationUnit compilationUnit= context.getAST();
		if (compilationUnit == null)
			return null;

		boolean convertFunctionalInterfaces= isEnabled(CleanUpConstants.CONVERT_FUNCTIONAL_INTERFACES);
		if (!convertFunctionalInterfaces)
			return null;

		return LambdaExpressionsFix.createCleanUp(compilationUnit,
				isEnabled(CleanUpConstants.USE_LAMBDA),
				isEnabled(CleanUpConstants.USE_ANONYMOUS_CLASS_CREATION));
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public String[] getStepDescriptions() {
		List<String> result= new ArrayList<String>();
		if (isEnabled(CleanUpConstants.CONVERT_FUNCTIONAL_INTERFACES)) {
			if (isEnabled(CleanUpConstants.USE_LAMBDA)) {
				result.add(MultiFixMessages.LambdaExpressionsCleanUp_use_lambda_where_possible);
			}
			if (isEnabled(CleanUpConstants.USE_ANONYMOUS_CLASS_CREATION)) {
				result.add(MultiFixMessages.LambdaExpressionsCleanUp_use_anonymous);
			}
		}

		return result.toArray(new String[result.size()]);
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public String getPreview() {
		StringBuffer buf= new StringBuffer();
		
		boolean convert= isEnabled(CleanUpConstants.CONVERT_FUNCTIONAL_INTERFACES);
		boolean useLambda= isEnabled(CleanUpConstants.USE_LAMBDA);
		boolean useAnonymous= isEnabled(CleanUpConstants.USE_ANONYMOUS_CLASS_CREATION);
		
		boolean firstLambda= convert && useLambda;
		boolean secondLambda= !(convert && useAnonymous);
		
		if (firstLambda) {
			buf.append("IntConsumer c = i -> {\n"); //$NON-NLS-1$
			buf.append("    System.out.println(i);\n"); //$NON-NLS-1$
			buf.append("};\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
		} else {
			buf.append("IntConsumer c = new IntConsumer() {\n"); //$NON-NLS-1$
			buf.append("    @Override public void accept(int value) {\n"); //$NON-NLS-1$
			buf.append("        System.out.println(i);\n"); //$NON-NLS-1$
			buf.append("    }\n"); //$NON-NLS-1$
			buf.append("};\n"); //$NON-NLS-1$
		}
		
		if (secondLambda) {
			buf.append("Runnable r = () -> { /* do something */ };\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
			buf.append("\n"); //$NON-NLS-1$
		} else {
			buf.append("Runnable r = new Runnable() {\n"); //$NON-NLS-1$
			buf.append("    @Override public void run() {\n"); //$NON-NLS-1$
			buf.append("        //do something\n"); //$NON-NLS-1$
			buf.append("    }\n"); //$NON-NLS-1$
			buf.append("};\n"); //$NON-NLS-1$
		}
		return buf.toString();
	}

}