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A Java implementation of the JSON Schema specification
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/*
 * Copyright (c) 2012, Francis Galiegue 
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the Lesser GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * Lesser GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see .
 */

package org.eel.kitchen.jsonschema.examples;

import com.fasterxml.jackson.databind.JsonNode;
import org.eel.kitchen.jsonschema.format.FormatAttribute;
import org.eel.kitchen.jsonschema.main.JsonSchema;
import org.eel.kitchen.jsonschema.main.JsonSchemaFactory;
import org.eel.kitchen.jsonschema.metaschema.KeywordRegistries;
import org.eel.kitchen.jsonschema.metaschema.KeywordRegistry;
import org.eel.kitchen.jsonschema.metaschema.SchemaURIs;
import org.eel.kitchen.jsonschema.ref.JsonRef;
import org.eel.kitchen.jsonschema.report.Message;
import org.eel.kitchen.jsonschema.report.ValidationReport;
import org.eel.kitchen.jsonschema.util.NodeType;

import java.io.IOException;
import java.util.UUID;

import static org.eel.kitchen.jsonschema.main.JsonSchemaFactory.*;

/**
 * Eighth example: augmenting schemas with custom format attributes
 *
 * link to source code
 *
 * link to schema
 *
 * This example adds a custom format attribute named {@code uuid}, which
 * checks whether a string instance is a valid UUID.
 *
 * This kind of customization requires three steps:
 *
 * 
 *     grabbing a {@link KeywordRegistry};
 *     augmenting it as needed;
 *     registering this registry to the {@link JsonSchemaFactory} (via a
 *     {@link Builder}, as for all customizations) with a matching URI.
 * 
 *
 * Here, we choose to augment draft v3. We can fetch the URI and default
 * keyword registry for this version using {@link
 * KeywordRegistries#draftV3Core()} and {@link SchemaURIs#draftV3Core()}
 * respectively. Note that the third argument to {@link
 * Builder#addKeywordRegistry(JsonRef, KeywordRegistry, boolean)} is {@code
 * true}, since we want to make this schema the default.
 *
 * Note also that the schema has no {@code $schema} defined; as a result, the
 * default schema is used (it is not recommended to omit {@code $schema}
 * in your own schemas).
 *
 * Adding a custom format attribute is done by extending the {@link
 * FormatAttribute} class.
 *
 * Two sample files are given: the first (link) is valid, the other (link) isn't (the provided {@code id}
 * for the second array element is invalid).
 */
public final class Example8
    extends ExampleBase
{
    public static void main(final String... args)
        throws IOException
    {
        final JsonNode customSchema = loadResource("/custom-fmt.json");
        final JsonNode good = loadResource("/custom-fmt-good.json");
        final JsonNode bad = loadResource("/custom-fmt-bad.json");

        final JsonRef ref = SchemaURIs.draftV3Core();
        final KeywordRegistry registry = KeywordRegistries.draftV3Core();

        registry.addFormatAttribute("uuid", UUIDFormatAttribute.getInstance());

        final JsonSchemaFactory factory = new JsonSchemaFactory.Builder()
            .addKeywordRegistry(ref, registry, true).build();

        final JsonSchema schema = factory.fromSchema(customSchema);

        ValidationReport report;

        report = schema.validate(good);
        printReport(report);

        report = schema.validate(bad);
        printReport(report);
    }

    private static final class UUIDFormatAttribute
        extends FormatAttribute
    {
        private static final FormatAttribute INSTANCE
            = new UUIDFormatAttribute();

        private UUIDFormatAttribute()
        {
            super(NodeType.STRING);
        }

        public static FormatAttribute getInstance()
        {
            return INSTANCE;
        }

        @Override
        public void checkValue(final String fmt, final ValidationReport report,
            final JsonNode value)
        {
            try {
                UUID.fromString(value.textValue());
            } catch (IllegalArgumentException ignored) {
                final Message.Builder msg = newMsg(fmt).addInfo("value", value)
                    .setMessage("string is not a valid UUID");
                report.addMessage(msg.build());
            }
        }

    }
}