LinkParameterValidators.java

package fr.openwide.core.wicket.more.link.descriptor.parameter.validator;

import java.io.Serializable;
import java.util.Collection;

import org.apache.wicket.request.mapper.parameter.PageParameters;
import org.apache.wicket.util.lang.Args;

import com.google.common.collect.ImmutableList;


public final class LinkParameterValidators {

	private LinkParameterValidators() { }

	/**
	 * @return True if the parameters model is valid according to the validator, false otherwise.
	 * @throws NullPointerException if <code>validator</code> is null.
	 */
	public static boolean isModelValid(ILinkParameterValidator validator) {
		Args.notNull(validator, "validator");
		
		LinkParameterValidationErrorCollector collector = new LinkParameterValidationErrorCollector();
		validator.validateModel(collector);

		Collection<ILinkParameterValidationErrorDescription> errors = collector.getErrors();
		return errors.isEmpty();
	}
	
	/**
	 * Checks that parameters model is valid according to a validator, throwing a {@link LinkParameterModelValidationException} if it is not.
	 * @throws LinkParameterModelValidationException if the parameters model is invalid according to the validator.
	 * @throws NullPointerException if <code>validator</code> is null.
	 */
	public static void checkModel(ILinkParameterValidator validator) throws LinkParameterModelValidationException {
		Args.notNull(validator, "validator");
		
		LinkParameterValidationErrorCollector collector = new LinkParameterValidationErrorCollector();
		validator.validateModel(collector);
		
		Collection<ILinkParameterValidationErrorDescription> errors = collector.getErrors();
		if ( ! errors.isEmpty() ) {
			throw new LinkParameterModelValidationException(errors);
		}
	}

	/**
	 * @return True if the serialized form of the parameters is valid according to the validator, false otherwise.
	 * @throws NullPointerException if <code>parameters</code> or <code>validator</code> is null.
	 */
	public static boolean isSerializedValid(PageParameters parameters, ILinkParameterValidator validator) {
		Args.notNull(parameters, "parameters");
		Args.notNull(validator, "validator");
		
		LinkParameterValidationErrorCollector collector = new LinkParameterValidationErrorCollector();
		validator.validateSerialized(parameters, collector);

		Collection<ILinkParameterValidationErrorDescription> errors = collector.getErrors();
		return errors.isEmpty();
	}
	
	/**
	 * Checks that the serialized form of the parameters is valid according to a validator, throwing a {@link LinkParameterSerializedFormValidationException} if it is not.
	 * @throws LinkParameterSerializedFormValidationException if the serialized form of the parameters is invalid according to the validator.
	 * @throws NullPointerException if <code>parameters</code> or <code>validator</code> is null.
	 */
	public static void checkSerialized(PageParameters parameters, ILinkParameterValidator validator) throws LinkParameterSerializedFormValidationException {
		Args.notNull(parameters, "parameters");
		Args.notNull(validator, "validator");
		
		LinkParameterValidationErrorCollector collector = new LinkParameterValidationErrorCollector();
		validator.validateSerialized(parameters, collector);
		
		Collection<ILinkParameterValidationErrorDescription> errors = collector.getErrors();
		if ( ! errors.isEmpty() ) {
			throw new LinkParameterSerializedFormValidationException(parameters, errors);
		}
	}
	
	/**
	 * Creates a validator that performs the validation sequentially with each validator in the given order.
	 * <p>The resulting validator is {@link Serializable} if <code>validators</code> is Serializable.
	 * @param validators The validators to be chained
	 * @return A validator chaining the given validators. If empty, no validation will be performed and no {@link ILinkParameterValidationErrorDescription error} will ever be reported.
	 * @throws NullPointerException if <code>validators</code> is null.
	 */
	public static ILinkParameterValidator chain(Iterable<? extends ILinkParameterValidator> validators) {
		Args.notNull(validators, "validators");
		return new ChainedParameterValidator(validators);
	}
	
	private static class ChainedParameterValidator implements ILinkParameterValidator {
		private static final long serialVersionUID = 1L;
		
		private final Iterable<? extends ILinkParameterValidator> validators;
		
		public ChainedParameterValidator(Iterable<? extends ILinkParameterValidator> validators) {
			super();
			this.validators = ImmutableList.copyOf(validators);
		}
		
		@Override
		public void validateSerialized(PageParameters parameters, LinkParameterValidationErrorCollector collector) {
			for (ILinkParameterValidator validator : validators) {
				validator.validateSerialized(parameters, collector);
			}
		}

		@Override
		public void validateModel(LinkParameterValidationErrorCollector collector) {
			for (ILinkParameterValidator validator : validators) {
				validator.validateModel(collector);
			}
		}

		@Override
		public void detach() {
			for (ILinkParameterValidator validator : validators) {
				validator.detach();
			}
		}
	}

}