net.derquinse.common.collect.FlatImmutableHierarchy.java Source code

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Here is the source code for net.derquinse.common.collect.FlatImmutableHierarchy.java

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/*
 * Copyright 2008 the original author or authors.
 *
 * 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 net.derquinse.common.collect;

import java.util.List;

import javax.annotation.Nullable;

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

/**
 * Implementation of {@link ImmutableHierarchy} with exactly one level.
 * @author Andres Rodriguez
 * @param <E> Type of the elements in the hierarchy.
 */
final class FlatImmutableHierarchy<E> extends ImmutableHierarchy<E> {
    private final ImmutableSet<E> set;

    FlatImmutableHierarchy(Iterable<? extends E> elements) {
        set = ImmutableSet.copyOf(elements);
    }

    @Override
    public ImmutableSet<E> elementSet() {
        return set;
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.collect.Hierarchy#getChildren(java.lang.Object)
     */
    public List<E> getChildren(@Nullable E element) {
        if (element == null) {
            return getFirstLevel();
        }
        checkMember(element);
        return ImmutableList.of();
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.collect.Hierarchy#getFirstLevel()
     */
    public List<E> getFirstLevel() {
        return set.asList();
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.collect.Hierarchy#getParent(java.lang.Object)
     */
    public E getParent(E element) {
        checkMember(element);
        return null;
    }
}