org.eclipse.modisco.infra.browser.custom/src/org/eclipse/gmt/modisco/infra/browser/custom/validation/EValidatorAdapter.java

/*******************************************************************************
 * Copyright (c) 2009 Mia-Software.
 * 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:
 *     Nicolas Bros (Mia-Software) - initial API and implementation
 *******************************************************************************/
package org.eclipse.gmt.modisco.infra.browser.custom.validation;

import java.util.Map;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.core.runtime.Status;
import org.eclipse.emf.common.util.BasicDiagnostic;
import org.eclipse.emf.common.util.DiagnosticChain;
import org.eclipse.emf.ecore.EClass;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.util.EObjectValidator;
import org.eclipse.emf.validation.model.EvaluationMode;
import org.eclipse.emf.validation.model.IConstraintStatus;
import org.eclipse.emf.validation.service.IBatchValidator;
import org.eclipse.emf.validation.service.ModelValidationService;

/**
 * An adapter that plugs the EMF Model Validation Service API into the
 * {@link org.eclipse.emf.ecore.EValidator} API.
 * @deprecated Will be replaced by EMF Facet,
 *             cf https://bugs.eclipse.org/bugs/show_bug.cgi?id=470715
 */
@Deprecated
public class EValidatorAdapter extends EObjectValidator {

	/**
	 * Model Validation Service interface for batch validation of EMF elements.
	 */
	private final IBatchValidator batchValidator;

	public EValidatorAdapter() {
		super();

		this.batchValidator = (IBatchValidator) ModelValidationService.getInstance().newValidator(
				EvaluationMode.BATCH);
		this.batchValidator.setIncludeLiveConstraints(true);
		this.batchValidator.setReportSuccesses(false);
	}

	@Override
	public boolean validate(final EObject eObject, final DiagnosticChain diagnostics,
			final Map<Object, Object> context) {
		return validate(eObject.eClass(), eObject, diagnostics, context);
	}

	/**
	 * Implements validation by delegation to the EMF validation framework.
	 */
	@Override
	public boolean validate(final EClass eClass, final EObject eObject,
			final DiagnosticChain diagnostics, final Map<Object, Object> context) {
		// first, do whatever the basic EcoreValidator does
		super.validate(eClass, eObject, diagnostics, context);

		IStatus status = Status.OK_STATUS;

		// no point in validating if we can't report results
		if (diagnostics != null) {
			/*
			 * if EMF Mode Validation Service already covered the sub-tree,
			 * which it does for efficient computation and error reporting, then
			 * don't repeat (the Diagnostician does the recursion externally).
			 * If there is no context map, then we can't help it
			 */
			if (!hasProcessed(eObject, context)) {
				status = this.batchValidator.validate(eObject, new NullProgressMonitor());
				processed(eObject, context, status);
				appendDiagnostics(status, diagnostics);
			}
		}

		return status.isOK();
	}

	/**
	 * If we have a context map, record this object's <code>status</code> in it
	 * so that we will know later that we have processed it and its sub-tree.
	 * 
	 * @param eObject
	 *            an element that we have validated
	 * @param context
	 *            the context (may be <code>null</code>)
	 * @param status
	 *            the element's validation status
	 */
	private void processed(final EObject eObject, final Map<Object, Object> context,
			final IStatus status) {
		if (context != null) {
			context.put(eObject, status);
		}
	}

	/**
	 * Determines whether we have processed this <code>eObject</code> before, by
	 * automatic recursion of the EMF Model Validation Service. This is only
	 * possible if we do, indeed, have a context.
	 * 
	 * @param eObject
	 *            an element to be validated (we hope not)
	 * @param context
	 *            the context (may be <code>null</code>)
	 * @return <code>true</code> if the context is not <code>null</code> and the
	 *         <code>eObject</code> or one of its containers has already been
	 *         validated; <code>false</code>, otherwise
	 */
	private boolean hasProcessed(final EObject eObject, final Map<Object, Object> context) {
		boolean result = false;
		EObject currentEObject = eObject;
		if (context != null) {
			// this is O(NlogN) but there's no helping it
			while (currentEObject != null) {
				if (context.containsKey(currentEObject)) {
					result = true;
					currentEObject = null;
				} else {
					currentEObject = currentEObject.eContainer();
				}
			}
		}

		return result;
	}

	/**
	 * Converts a status result from the EMF validation service to diagnostics.
	 * 
	 * @param status
	 *            the EMF validation service's status result
	 * @param diagnostics
	 *            a diagnostic chain to accumulate results on
	 */
	private void appendDiagnostics(final IStatus status, final DiagnosticChain diagnostics) {
		if (status.isMultiStatus()) {
			IStatus[] children = status.getChildren();

			for (int i = 0; i < children.length; i++) {
				appendDiagnostics(children[i], diagnostics);
			}
		} else if (status instanceof IConstraintStatus) {
			diagnostics.add(new BasicDiagnostic(status.getSeverity(), status.getPlugin(), status
					.getCode(), status.getMessage(), ((IConstraintStatus) status).getResultLocus()
					.toArray()));
		}
	}

}