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

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

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/*
 * Copyright 2008-2010 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 com.google.common.base.Functions;
import com.google.common.collect.ImmutableBiMap;

/**
 * An immutable and thread-safe implementation of IndexedHierarchy.
 * @author Andres Rodriguez
 * @param <K> Type of the keys.
 * @param <V> Type of the values.
 */
final class RegularImmutableIndexedHierarchy<K, V> extends ImmutableIndexedHierarchy<K, V> {
    /** Backing map. */
    private final ImmutableBiMap<K, V> map;
    /** Keys hierarchy. */
    private final ImmutableHierarchy<K> keys;
    /** Values hierarchy. */
    private final ImmutableHierarchy<V> values;
    /** Inverse hierarchy. */
    private final Inverse inverse = new Inverse();

    /**
     * Constructor.
     * @param map Backing map.
     * @param keys Keys hierarchy.
     */
    RegularImmutableIndexedHierarchy(ImmutableBiMap<K, V> map, ImmutableHierarchy<K> keys) {
        check(map, keys);
        this.map = map;
        ImmutableHierarchy.Builder<V> builder = ImmutableHierarchy.builder(true);
        for (K key : keys) {
            final K parentKey = keys.getParent(key);
            final V parentValue = parentKey != null ? map.get(parentKey) : null;
            builder.add(parentValue, map.get(key));
        }
        this.values = ImmutableHierarchy.<V>builder().addHierarchy(null, keys, null, false, Functions.forMap(map))
                .get();
        this.keys = keys;
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.collect.ForwardingHierarchy#delegate()
     */
    @Override
    protected Hierarchy<V> delegate() {
        return values;
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.collect.ImmutableIndexedHierarchy#asMap()
     */
    @Override
    public ImmutableBiMap<K, V> asMap() {
        return map;
    }

    /*
     * (non-Javadoc)
     * @see net.derquinse.common.collect.IndexedHierarchy#inverse()
     */
    public IndexedHierarchy<V, K> inverse() {
        return inverse;
    }

    /* Inverse hierarchy. */
    private final class Inverse extends ImmutableIndexedHierarchy<V, K> {
        /*
         * (non-Javadoc)
         * @see net.derquinse.common.collect.ForwardingHierarchy#delegate()
         */
        @Override
        protected Hierarchy<K> delegate() {
            return keys;
        }

        /*
         * (non-Javadoc)
         * @see net.derquinse.common.collect.ImmutableIndexedHierarchy#asMap()
         */
        @Override
        public ImmutableBiMap<V, K> asMap() {
            return map.inverse();
        }

        /*
         * (non-Javadoc)
         * @see net.derquinse.common.collect.IndexedHierarchy#inverse()
         */
        public IndexedHierarchy<K, V> inverse() {
            return RegularImmutableIndexedHierarchy.this;
        }
    }

}