com.cloudera.nav.sdk.client.writer.registry.RegistryEntryFactory.java Source code

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Here is the source code for com.cloudera.nav.sdk.client.writer.registry.RegistryEntryFactory.java

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/*
 * Copyright (c) 2015 Cloudera, 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.cloudera.nav.sdk.client.writer.registry;

import com.cloudera.nav.sdk.model.MClassUtil;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.collect.Lists;

import java.beans.IntrospectionException;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Map;

/**
 * Abstract factory for creating a new registry of MClass objects
 * @param <T> the type of registry entries
 */
public abstract class RegistryEntryFactory<T> {

    private static final int MAX_CACHE_SIZE = 100;

    public LoadingCache<Class<?>, Collection<T>> newRegistry() {
        return CacheBuilder.newBuilder().maximumSize(MAX_CACHE_SIZE)
                .build(new CacheLoader<Class<?>, Collection<T>>() {
                    @Override
                    public Collection<T> load(Class<?> aClass) throws Exception {
                        return parseMClass(aClass);
                    }
                });
    }

    private Collection<T> parseMClass(Class<?> aClass) throws IntrospectionException {
        Map<Field, Method> annInfo = MClassUtil.getAnnotatedProperties(aClass, getTypeClass());
        Collection<T> properties = Lists.newLinkedList();
        for (Map.Entry<Field, Method> entry : annInfo.entrySet()) {
            properties.add(createEntry(entry.getKey(), entry.getValue()));
        }
        return properties;
    }

    protected abstract Class<? extends Annotation> getTypeClass();

    protected abstract T createEntry(Field field, Method getter);
}