com.google.gwt.validation.client.impl.Validation.java Source code

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Here is the source code for com.google.gwt.validation.client.impl.Validation.java

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/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.validation.client.impl;

import com.google.gwt.core.client.GWT;

import java.util.List;

import javax.validation.Configuration;
import javax.validation.ValidationException;
import javax.validation.ValidationProviderResolver;
import javax.validation.ValidatorFactory;
import javax.validation.bootstrap.GenericBootstrap;
import javax.validation.bootstrap.ProviderSpecificBootstrap;
import javax.validation.spi.BootstrapState;
import javax.validation.spi.ValidationProvider;

/**
 * This class is the entry point for Bean Validation. Bootstrapping is done as follows:
 * 
 * <pre>{@code ValidatorFactory factory = Validation.buildDefaultValidatorFactory();}</pre>
 * 
 * Or, equivalently:
 * 
 * <pre>{@code
 * Configuration<?> configuration = Validation
 *    .byDefaultProvider()
 *    .configure();
 * ValidatorFactory factory = configuration.buildValidatorFactory();}
 * </pre>
 * 
 * Only the default provider is available for use, and thus the {@code byProvider} and 
 * {@code providerResolver} methods are not supported. Calling either of these methods will
 * generate an exception.
 * <p>
 * This class was modified by Google from the original
 * javax.validation.Validation source to make it suitable for GWT.
 */
public class Validation {

    // private class, not exposed
    private static class GenericGWTBootstrapImpl implements GenericBootstrap, BootstrapState {

        private ValidationProviderResolver defaultResolver;

        @Override
        public Configuration<?> configure() {
            ValidationProviderResolver aResolver = getDefaultValidationProviderResolver();

            List<ValidationProvider<?>> resolvers;
            try {
                resolvers = aResolver.getValidationProviders();
            } catch (RuntimeException re) {
                throw new ValidationException("Unable to get available provider resolvers.", re);
            }

            if (resolvers.size() == 0) {
                // FIXME looks like an assertion error almost
                throw new ValidationException("Unable to find a default provider");
            }

            Configuration<?> config;
            try {
                config = aResolver.getValidationProviders().get(0).createGenericConfiguration(this);
            } catch (RuntimeException re) {
                throw new ValidationException("Unable to instantiate Configuration.", re);
            }

            return config;
        }

        @Override
        public ValidationProviderResolver getDefaultValidationProviderResolver() {
            if (defaultResolver == null) {
                defaultResolver = GWT.create(ValidationProviderResolver.class);
            }
            return defaultResolver;
        }

        @Override
        public ValidationProviderResolver getValidationProviderResolver() {
            return getDefaultValidationProviderResolver();
        }

        /**
         * Unsupported. Always throws an {@link UnsupportedOperationException}.
         * 
         * @throws UnsupportedOperationException
         */
        @Override
        public GenericBootstrap providerResolver(ValidationProviderResolver resolver) {
            throw new UnsupportedOperationException(
                    "GWT Validation does not support custom validator " + "provider resolvers");
        }
    }

    /**
     * Build and return a <code>ValidatorFactory</code> instance based on the
     * default Bean Validation provider.
     * <p/>
     * The provider list is resolved using the default validation provider
     * resolver logic.
     * <p/>
     * The code is semantically equivalent to
     * <code>Validation.byDefaultProvider().configure().buildValidatorFactory()</code>
     * 
     * @return <code>ValidatorFactory</code> instance.
     * 
     * @throws ValidationException if the ValidatorFactory cannot be built
     */
    public static ValidatorFactory buildDefaultValidatorFactory() {
        return byDefaultProvider().configure().buildValidatorFactory();
    }

    /**
     * Build a <code>Configuration</code>.
     *
     * <pre>
     * Configuration&lt?&gt; configuration = Validation
     *    .byDefaultProvider()
     *    .configure();
     * ValidatorFactory factory = configuration.buildValidatorFactory();
     * </pre>
     *
     * The first available provider will be returned.
     *
     * @return instance building a generic <code>Configuration</code> complaint
     *         with the bootstrap state provided.
     */
    public static GenericBootstrap byDefaultProvider() {
        return new GenericGWTBootstrapImpl();
    }

    /**
     * Unsupported. Always throws an {@link UnsupportedOperationException}.
     * @param providerType 
     * 
     * @throws UnsupportedOperationException
     */
    public static <T extends Configuration<T>, U extends ValidationProvider<T>> ProviderSpecificBootstrap<T> byProvider(
            Class<U> providerType) {
        throw new UnsupportedOperationException("GWT Validation does not support custom validator " + "providers");
    }
}