Example usage for com.google.common.collect ImmutableBiMap isEmpty

Introduction

In this page you can find the example usage for com.google.common.collect ImmutableBiMap isEmpty.

Prototype

boolean isEmpty();

Source Link

Document

Returns true if this map contains no key-value mappings.

Usage

From source file:net.derquinse.common.collect.ImmutableIndexedHierarchy.java

/**
 * Builds an immutable indexed hierarchy from a set of values.
 * @param elements Source elements.//w  w  w . jav a  2s .c  om
 * @param key Key function.
 * @param parentKey Parent key function.
 * @param value Value function.
 */
public static <T, K, V> ImmutableIndexedHierarchy<K, V> of(Iterable<? extends T> elements,
        Function<? super T, ? extends K> key, Function<? super T, ? extends K> parentKey,
        Function<? super T, ? extends V> value) {
    checkNotNull(elements, "The source elements must be provided.");
    checkNotNull(key, "The key function must be provided.");
    checkNotNull(parentKey, "The parent key function must be provided.");
    checkNotNull(value, "The value function must be provided.");
    ImmutableHierarchy.Builder<K> h = ImmutableHierarchy.builder(true);
    ImmutableBiMap.Builder<K, V> m = ImmutableBiMap.builder();
    for (T element : elements) {
        final K k = key.apply(element);
        m.put(k, value.apply(element));
        h.add(parentKey.apply(element), k);
    }
    final ImmutableBiMap<K, V> biMap = m.build();
    if (biMap.isEmpty()) {
        return of();
    }
    return new RegularImmutableIndexedHierarchy<K, V>(biMap, h.get());
}

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