io.soliton.shapeshifter.SchemaRegistry.java Source code

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Here is the source code for io.soliton.shapeshifter.SchemaRegistry.java

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/**
 * Copyright 2012, 2013 Turn, 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 io.soliton.shapeshifter;

import com.turn.shapeshifter.ShapeshifterProtos.JsonSchema;

import java.util.Iterator;
import java.util.List;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ExecutionException;

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 com.google.common.collect.ImmutableList;
import com.google.common.collect.MapMaker;
import com.google.common.util.concurrent.UncheckedExecutionException;
import com.google.protobuf.Descriptors;
import com.google.protobuf.Descriptors.Descriptor;

/**
 * A container of schemas.
 *
 * @author jsilland
 * @see ReadableSchemaRegistry
 * @see WritableSchemaRegistry
 */
public class SchemaRegistry implements ReadableSchemaRegistry, WritableSchemaRegistry {

    private final ConcurrentMap<String, NamedSchema> schemas;
    private final LoadingCache<Descriptors.Descriptor, AutoSchema> autoSchemas;

    private static final CacheLoader<Descriptors.Descriptor, AutoSchema> AUTO_SCHEMA_LOADER = new CacheLoader<Descriptors.Descriptor, AutoSchema>() {

        @Override
        public AutoSchema load(Descriptor key) throws Exception {
            return AutoSchema.of(key);
        }
    };

    /**
     * Creates a new, empty registry.
     */
    public SchemaRegistry() {
        this(CacheBuilder.newBuilder());
    }

    /**
     * Constructs a new instance of this class with the given caching policy.
     *
     * @param cacheBuilder a configured {@link CacheBuilder} for storing
     *                     instances of automatically generated schema
     */
    public SchemaRegistry(CacheBuilder<Object, Object> cacheBuilder) {
        Preconditions.checkNotNull(cacheBuilder);
        this.schemas = new MapMaker().makeMap();
        this.autoSchemas = cacheBuilder.build(AUTO_SCHEMA_LOADER);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void register(NamedSchema schema) {
        Preconditions.checkNotNull(schema);
        schemas.put(schema.getName(), schema);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public NamedSchema get(String name) {
        Preconditions.checkNotNull(name);
        return schemas.get(name);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public AutoSchema get(final Descriptors.Descriptor descriptor) throws SchemaObtentionException {
        try {
            return autoSchemas.get(descriptor);
        } catch (ExecutionException ee) {
            throw new SchemaObtentionException(ee);
        } catch (UncheckedExecutionException uee) {
            throw new SchemaObtentionException(uee);
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public List<JsonSchema> getJsonSchemas() throws JsonSchemaException {
        ImmutableList.Builder<JsonSchema> jsonSchemas = ImmutableList.builder();
        for (NamedSchema schema : schemas.values()) {
            jsonSchemas.add(schema.getJsonSchema(this));
        }
        return jsonSchemas.build();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean contains(String name) {
        return schemas.containsKey(name);
    }

    /**
     * Returns the set of schemas registered in this instance.
     */
    public Iterator<NamedSchema> getSchemas() {
        return schemas.values().iterator();
    }
}