org.eel.kitchen.jsonschema.ref.SchemaRegistry.java Source code

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Here is the source code for org.eel.kitchen.jsonschema.ref.SchemaRegistry.java

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/*
 * Copyright (c) 2012, Francis Galiegue <fgaliegue@gmail.com>
 *
 * 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 <http://www.gnu.org/licenses/>.
 */

package org.eel.kitchen.jsonschema.ref;

import com.fasterxml.jackson.databind.JsonNode;
import com.google.common.base.Preconditions;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import org.eel.kitchen.jsonschema.main.JsonSchemaException;
import org.eel.kitchen.jsonschema.report.Domain;
import org.eel.kitchen.jsonschema.report.Message;
import org.eel.kitchen.jsonschema.uri.URIManager;

import java.net.URI;
import java.util.concurrent.ExecutionException;

/**
 * A JSON Schema registry
 *
 * <p>All schema registering and downloading is done through this class.</p>
 *
 * <p>Note that if the id of a schema is not absolute (that is, the URI itself
 * is absolute and it has no fragment part, or an empty fragment), then the
 * whole schema will be considered anonymous.</p>
 *
 * <p>This class is thread safe.</p>
 */
public final class SchemaRegistry {
    /**
     * The default namespace
     */
    private final JsonRef namespace;

    /**
     * Schema cache
     */
    private final LoadingCache<URI, SchemaContainer> cache;

    /**
     * Constructor
     *
     * @param manager the URI manager to use
     * @param namespace this registry's namespace
     */
    public SchemaRegistry(final URIManager manager, final URI namespace) {
        this.namespace = JsonRef.fromURI(namespace);
        cache = CacheBuilder.newBuilder().maximumSize(100L).build(new CacheLoader<URI, SchemaContainer>() {
            @Override
            public SchemaContainer load(final URI key) throws JsonSchemaException {
                return new SchemaContainer(key, manager.getContent(key));
            }
        });
    }

    /**
     * Register a schema
     *
     * @param schema the schema to register
     * @return a schema container
     */
    public SchemaContainer register(final JsonNode schema) {
        Preconditions.checkNotNull(schema, "cannot register null schema");

        final SchemaContainer container = new SchemaContainer(schema);

        final JsonRef ref = container.getLocator();

        if (ref.isAbsolute())
            cache.put(ref.getLocator(), container);

        return container;
    }

    /**
     * Get a schema container from the given URI
     *
     * <p>Note that if the URI is relative, it will be resolved against this
     * registry's namespace, if any.</p>
     *
     * @param uri the URI
     * @return a schema container
     * @throws JsonSchemaException impossible to get content at this URI
     */
    public SchemaContainer get(final URI uri) throws JsonSchemaException {
        final URI realURI = namespace.resolve(JsonRef.fromURI(uri)).toURI();

        try {
            return cache.get(realURI);
        } catch (ExecutionException e) {
            final Message.Builder msg = Domain.REF_RESOLVING.newMessage().setKeyword("N/A")
                    .setMessage("failed to get content from URI").addInfo("uri", realURI)
                    .addInfo("exception-class", e.getCause().getClass().getName())
                    .addInfo("exception-message", e.getCause().getMessage());
            throw new JsonSchemaException(msg.build());
        }
    }
}