ValidatorCollection.java

/*******************************************************************************
 * Copyright (c) 2007, 2014 compeople AG 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:
 *    compeople AG - initial API and implementation
 *******************************************************************************/
package org.eclipse.riena.ui.ridgets.validation;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;

import org.eclipse.core.databinding.validation.IValidator;
import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.IStatus;

/**
 * A joined validator, which is a collection of rules to be invoked in the order they are added to this rule.
 */
public class ValidatorCollection implements IValidator, Iterable<IValidator> {

	private final Collection<IValidator> validators = new HashSet<IValidator>(2);

	/**
	 * Gets an unmodifiable copy of the validators used by this ValidatorCollection. Adding and removing single validators must be done through this class'
	 * methods {@link #add(IValidator)} and {@link #remove(IValidator)}.
	 * 
	 * @return a new unmodifiable collection, which contains all validators uses in this collection.
	 */
	public Collection<IValidator> getValidators() {
		return Collections.unmodifiableCollection(new ArrayList<IValidator>(validators));
	}

	/**
	 * Returns an unmodifiable iterator which iterates over the used validators. Removing a rule must be done through this class' {@link #remove(IValidator)}
	 * method.
	 * 
	 * @see java.lang.Iterable#iterator()
	 */
	public Iterator<IValidator> iterator() {
		return getValidators().iterator();
	}

	/**
	 * Adds a validator to the collection.
	 * <p>
	 * Adding the same validator several times has no effect.
	 * 
	 * @param validator
	 *            The validator to add (non-null).,
	 * @return <code>true</code> if this collection changed as a result of the call
	 * @throws RuntimeException
	 *             if validator is <code>null</code>
	 * @since 4.0
	 */
	public boolean add(final IValidator validator) {
		Assert.isNotNull(validator);
		return validators.add(validator);
	}

	/**
	 * Removes a validator from the collection.
	 * 
	 * @param validator
	 *            The validator to remove.
	 * @return <code>true</code> if this collection changed as a result of the call
	 * @throws RuntimeException
	 *             if validator is <code>null</code>
	 * @since 4.0
	 */
	public boolean remove(final IValidator validator) {
		Assert.isNotNull(validator);
		return validators.remove(validator);
	}

	/**
	 * Returns true if the given validator is contained in this collection; false otherwise.
	 * 
	 * @param validator
	 *            a IValidator instance (may be null)
	 */
	public boolean contains(final IValidator validator) {
		return validators.contains(validator);
	}

	/**
	 * Validates the value using all validators and returns a joined status.
	 * 
	 * @param value
	 *            the value to validate
	 * 
	 * @see IValidator#validate(java.lang.Object)
	 */
	public IStatus validate(final Object value) {
		return validate(value, null);
	}

	/**
	 * Validates the value using all validators, notified the supplied {@link IValidationCallback} instance and returns a joined status.
	 * 
	 * @param value
	 *            the value to validate
	 * @param callback
	 *            an {@link IValidationCallback} instance; may be null
	 * 
	 * @since 1.2
	 */
	public IStatus validate(final Object value, final IValidationCallback callback) {
		final IStatus[] statuses = new IStatus[validators.size()];
		int index = -1;
		for (final IValidator validator : validators) {
			statuses[++index] = validator.validate(value);
			if (callback != null) {
				callback.validationRuleChecked(validator, statuses[index]);
			}
		}
		final IStatus result = ValidationRuleStatus.join(statuses);
		if (callback != null) {
			callback.validationResult(result);
		}
		return result;
	}
}