/*
 * Copyright (C) 2007 The Guava 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 org.glassfish.jersey.internal.guava;

import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.function.Predicate;

import static org.glassfish.jersey.internal.guava.Preconditions.checkNotNull;

This class contains static utility methods that operate on or return objects of type Iterable. Except as noted, each method has a corresponding Iterator-based method in the Iterators class. 

Performance notes: Unless otherwise noted, all of the iterables
produced in this class are lazy, which means that their iterators
only advance the backing iteration when absolutely necessary.

See the Guava User Guide article on  Iterables.
Author:
Kevin Bourrillion, Jared Levy
Since:
2.0 (imported from Google Collections Library)/**
 * This class contains static utility methods that operate on or return objects
 * of type {@code Iterable}. Except as noted, each method has a corresponding
 * {@link Iterator}-based method in the {@link Iterators} class.
 * <p>
 * <p><i>Performance notes:</i> Unless otherwise noted, all of the iterables
 * produced in this class are <i>lazy</i>, which means that their iterators
 * only advance the backing iteration when absolutely necessary.
 * <p>
 * <p>See the Guava User Guide article on <a href=
 * "http://code.google.com/p/guava-libraries/wiki/CollectionUtilitiesExplained#Iterables">
 * {@code Iterables}</a>.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @since 2.0 (imported from Google Collections Library)
 */
final class Iterables {
    private Iterables() {
    }

    
Returns the first element in iterable or defaultValue if the iterable is empty. The Iterators analog to this method is Iterators.getNext. 

If no default value is desired (and the caller instead wants a NoSuchElementException to be thrown), it is recommended that iterable.iterator().next() is used instead. 
Params:
defaultValue – the default value to return if the iterable is empty
Returns:
the first element of iterable or the default value
Since:
7.0/**
     * Returns the first element in {@code iterable} or {@code defaultValue} if
     * the iterable is empty.  The {@link Iterators} analog to this method is
     * {@link Iterators#getNext}.
     * <p>
     * <p>If no default value is desired (and the caller instead wants a
     * {@link NoSuchElementException} to be thrown), it is recommended that
     * {@code iterable.iterator().next()} is used instead.
     *
     * @param defaultValue the default value to return if the iterable is empty
     * @return the first element of {@code iterable} or the default value
     * @since 7.0
     */
    public static <T> T getFirst(Iterable<? extends T> iterable, T defaultValue) {
        return Iterators.getNext(iterable.iterator(), defaultValue);
    }

}