AQLInterpreter.java example

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eef-master
/*******************************************************************************
 * Copyright (c) 2016 Obeo.
 * 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:
 *    Obeo - initial API and implementation
 *******************************************************************************/
package org.eclipse.eef.tests.internal;

import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;

import java.util.Map;
import java.util.concurrent.ExecutionException;

import org.eclipse.acceleo.query.runtime.EvaluationResult;
import org.eclipse.acceleo.query.runtime.IQueryBuilderEngine;
import org.eclipse.acceleo.query.runtime.IQueryBuilderEngine.AstResult;
import org.eclipse.acceleo.query.runtime.IQueryEnvironment;
import org.eclipse.acceleo.query.runtime.IQueryEvaluationEngine;
import org.eclipse.acceleo.query.runtime.Query;
import org.eclipse.acceleo.query.runtime.QueryEvaluation;
import org.eclipse.acceleo.query.runtime.QueryParsing;
import org.eclipse.acceleo.query.runtime.ServiceUtils;
import org.eclipse.emf.common.util.BasicDiagnostic;
import org.eclipse.emf.common.util.Diagnostic;
import org.eclipse.emf.ecore.EcorePackage;
import org.eclipse.emf.ecore.impl.EStringToStringMapEntryImpl;
import org.eclipse.sirius.common.interpreter.api.IEvaluationResult;
import org.eclipse.sirius.common.interpreter.api.IInterpreter;

/**
 * An AQL interpreter used for tests.
 *
 * @author sbegaudeau
 */
public class AQLInterpreter implements IInterpreter {

	/**
	 * The prefix used by AQL expressions.
	 */
	private static final String AQL_PREFIX = "aql:"; //$NON-NLS-1$

	/**
	 * The cache of the expressions parsed.
	 */
	private LoadingCache<String, AstResult> parsedExpressions;

	/**
	 * The query environment.
	 */
	private IQueryEnvironment queryEnvironment;

	/**
	 * The constructor.
	 */
	public AQLInterpreter() {
		this.queryEnvironment = Query.newEnvironmentWithDefaultServices(null);
		this.queryEnvironment.registerEPackage(EcorePackage.eINSTANCE);
		ServiceUtils.registerServices(this.queryEnvironment, ServiceUtils.getServices(this.queryEnvironment, EEFTestServices.class));
		this.queryEnvironment.registerCustomClassMapping(EcorePackage.eINSTANCE.getEStringToStringMapEntry(), EStringToStringMapEntryImpl.class);
		initExpressionsCache();
	}

	/**
	 * Initializes the cache of the expressions.
	 */
	private void initExpressionsCache() {
		final IQueryBuilderEngine builder = QueryParsing.newBuilder(queryEnvironment);
		final int maxCacheSize = 500;
		this.parsedExpressions = CacheBuilder.newBuilder().maximumSize(maxCacheSize).build(new CacheLoader<String, AstResult>() {
			@Override
			public AstResult load(String key) throws Exception {
				return builder.build(key);
			}

		});
	}

	/**
	 * {@inheritDoc}
	 *
	 * @see org.eclipse.sirius.common.interpreter.api.IInterpreter#evaluateExpression(java.util.Map, java.lang.String)
	 */
	@Override
	public IEvaluationResult evaluateExpression(Map<String, Object> variables, String expressionBody) {
		String expression = expressionBody;
		if (expression.startsWith(AQL_PREFIX)) {
			expression = expression.substring(AQL_PREFIX.length());
		}

		try {
			AstResult build = parsedExpressions.get(expression);
			IQueryEvaluationEngine evaluationEngine = QueryEvaluation.newEngine(queryEnvironment);
			final EvaluationResult evalResult = evaluationEngine.eval(build, variables);

			final BasicDiagnostic diagnostic = new BasicDiagnostic();
			if (Diagnostic.OK != build.getDiagnostic().getSeverity()) {
				diagnostic.merge(build.getDiagnostic());
			}
			if (Diagnostic.OK != evalResult.getDiagnostic().getSeverity()) {
				diagnostic.merge(evalResult.getDiagnostic());
			}

			return org.eclipse.sirius.common.interpreter.api.EvaluationResult.of(evalResult.getResult(), diagnostic);
		} catch (ExecutionException e) {
			throw new IllegalStateException(e);
		}
	}

}