com.intelligentsia.dowsers.entity.meta.provider.MetaEntityProviderComposite.java Source code

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Here is the source code for com.intelligentsia.dowsers.entity.meta.provider.MetaEntityProviderComposite.java

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/**
 *        Licensed to the Apache Software Foundation (ASF) under one
 *        or more contributor license agreements.  See the NOTICE file
 *        distributed with this work for additional information
 *        regarding copyright ownership.  The ASF licenses this file
 *        to you 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.intelligentsia.dowsers.entity.meta.provider;

import java.util.Arrays;
import java.util.Collection;

import com.google.common.base.Preconditions;
import com.google.common.collect.Sets;
import com.intelligentsia.dowsers.entity.meta.MetaEntity;
import com.intelligentsia.dowsers.entity.meta.MetaEntityProvider;
import com.intelligentsia.dowsers.entity.reference.Reference;

/**
 * <code>MetaEntityProviderComposite</code> aggregate {@link MetaEntity}
 * definition from multiple {@link MetaEntityProvider}.
 * 
 * @author <a href="mailto:jguibert@intelligents-ia.com">Jerome Guibert</a>
 * 
 */
public class MetaEntityProviderComposite implements MetaEntityProvider {

    /**
     * Aggregation of {@link MetaEntityProvider}.
     */
    private final Collection<MetaEntityProvider> metaEntityProviders;

    /**
     * Build a new instance of <code>MetaEntityProviderComposite</code>.
     * 
     * @param metaEntityProviders
     *            {@link MetaEntityProvider}'s
     * @throws NullPointerException
     *             if metaEntityProviders is null
     */
    public MetaEntityProviderComposite(final MetaEntityProvider... metaEntityProviders)
            throws NullPointerException {
        this(Arrays.asList(metaEntityProviders));
    }

    /**
     * Build a new instance of <code>MetaEntityProviderComposite</code>.
     * 
     * @param metaEntityProviders
     *            collection of {@link MetaEntityProvider}
     * @throws NullPointerException
     *             if metaEntityProviders is null
     */
    public MetaEntityProviderComposite(final Collection<MetaEntityProvider> metaEntityProviders)
            throws NullPointerException {
        super();
        this.metaEntityProviders = Preconditions.checkNotNull(metaEntityProviders);
    }

    @Override
    public Collection<MetaEntity> find(final Reference reference) throws NullPointerException {
        Preconditions.checkNotNull(reference);
        final Collection<MetaEntity> result = Sets.newLinkedHashSet();
        for (final MetaEntityProvider provider : metaEntityProviders) {
            result.addAll(provider.find(reference));
        }
        return result;
    }

}