eu.eidas.auth.commons.attribute.FileAttributeDefinitionDao.java Source code

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Here is the source code for eu.eidas.auth.commons.attribute.FileAttributeDefinitionDao.java

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/*
 * This work is Open Source and licensed by the European Commission under the
 * conditions of the European Public License v1.1
 *
 * (http://www.osor.eu/eupl/european-union-public-licence-eupl-v.1.1);
 *
 * any use of this file implies acceptance of the conditions of this license.
 * 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 eu.eidas.auth.commons.attribute;

import java.util.HashSet;
import java.util.Set;

import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;
import javax.annotation.concurrent.ThreadSafe;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSortedSet;

import eu.eidas.auth.commons.io.SingletonAccessor;
import eu.eidas.auth.commons.io.SingletonAccessors;
import eu.eidas.util.Preconditions;

/**
 * A registry of {@link AttributeDefinition}s based on files on the classpath or on the filesystem.
 * <p>
 * The given file must comply with the attribute registry format (see {@link AttributeSetPropertiesConverter}.
 * <p>
 * If the configuration files are available as a file in the classpath or on the filesystem, then they are reloaded
 * automatically when their last-modified-date changes.
 * <p>
 * If the configuration files are available inside a jar in the classpath, then they are loaded once and for all and
 * cannot be reloaded.
 *
 * @see AttributeSetPropertiesConverter
 * @since 1.1
 */
@Immutable
@ThreadSafe
final class FileAttributeDefinitionDao implements AttributeDefinitionDao {

    private static SingletonAccessor<ImmutableSortedSet<AttributeDefinition<?>>> newSingletonAccessor(
            @Nonnull String fileName) {
        return SingletonAccessors.newPropertiesAccessor(fileName, AttributeSetPropertiesConverter.INSTANCE);
    }

    private static ImmutableList<SingletonAccessor<ImmutableSortedSet<AttributeDefinition<?>>>> newSingletonAccessors(
            @Nonnull String fileName, @Nonnull String[] fileNames) {
        ImmutableList.Builder<SingletonAccessor<ImmutableSortedSet<AttributeDefinition<?>>>> builder = new ImmutableList.Builder<>();
        Set<String> duplicates = new HashSet<>();
        duplicates.add(fileName);
        builder.add(newSingletonAccessor(fileName));
        for (final String name : fileNames) {
            if (duplicates.add(name)) {
                builder.add(newSingletonAccessor(name));
            }
        }
        return builder.build();
    }

    @Nonnull
    private final ImmutableList<SingletonAccessor<ImmutableSortedSet<AttributeDefinition<?>>>> accessors;

    /**
     * Creates an attribute registry based on the given configuration file.
     * <p>
     * The given file must comply with the attribute registry format (see {@link AttributeSetPropertiesConverter}.
     *
     * @param fileName the name of the configuration file.
     */
    FileAttributeDefinitionDao(@Nonnull String fileName) {
        Preconditions.checkNotNull(fileName, "fileName");
        accessors = ImmutableList.of(newSingletonAccessor(fileName));
    }

    /**
     * Creates an attribute registry based on the given configuration files.
     * <p>
     * The given files must comply with the attribute registry format (see {@link AttributeSetPropertiesConverter}.
     *
     * @param fileName the name of the first configuration file.
     * @param fileNames the names of the other configuration files.
     */
    FileAttributeDefinitionDao(@Nonnull String fileName, @Nonnull String... fileNames) {
        Preconditions.checkNotNull(fileName, "fileName");
        Preconditions.checkNotNull(fileNames, "fileNames");
        accessors = newSingletonAccessors(fileName, fileNames);
    }

    @Nonnull
    @Override
    public ImmutableList<? extends SingletonAccessor<ImmutableSortedSet<AttributeDefinition<?>>>> getAttributeDefinitionAccessors() {
        return accessors;
    }
}