de.flapdoodle.guava.Expectations.java Source code

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Here is the source code for de.flapdoodle.guava.Expectations.java

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/**
 * Copyright (C) 2013
 *   Michael Mosmann <michael@mosmann.de>
 *
 * 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 de.flapdoodle.guava;

import java.util.Collection;
import java.util.Iterator;

import com.google.common.base.Optional;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.Collections2;
import com.google.common.collect.Iterables;

public abstract class Expectations {

    private Expectations() {
        // no instance
    }

    private static <T> Optional<T> intNoneOrOne(Iterator<T> iterator) {
        Preconditions.checkNotNull(iterator, "iterator is null");
        if (!iterator.hasNext()) {
            return Optional.absent();
        }
        return Optional.of(iterator.next());
    }

    /**
     * gives one, if only one value exist
     * gives none on everything else
     * 
     * @param values
     * @return optional
     */
    public static <T> Optional<T> noneOrOneIfOnlyOne(Iterator<T> iterator) {
        Optional<T> ret = intNoneOrOne(iterator);
        if (iterator.hasNext()) {
            return Optional.absent();
        }
        return ret;
    }

    /**
     * gives one, if only one value exist
     * gives none on everything else
     * 
     * @param values
     * @return optional
     */
    public static <T> Optional<T> noneOrOneIfOnlyOne(Iterable<T> values) {
        Preconditions.checkNotNull(values, "values is null");
        return noneOrOneIfOnlyOne(values.iterator());
    }

    /**
     * gives first value, if one value exist
     * gives defaultValue if empty or more than one value exist,
     * 
     * @param values
     * @return value
     */
    public static <T> T oneIfOnlyOne(Iterator<T> iterator, T defaultValue) {
        return noneOrOneIfOnlyOne(iterator).or(Optional.fromNullable(defaultValue)).orNull();
    }

    /**
     * gives first value, if one value exist
     * gives defaultValue if empty or more than one value exist,
     * 
     * @param values
     * @return value
     */
    public static <T> T oneIfOnlyOne(Iterable<T> values, T defaultValue) {
        Preconditions.checkNotNull(values, "values is null");
        return oneIfOnlyOne(values.iterator(), defaultValue);
    }

    /**
     * gives none if empty, one if one element, fails if more than one
     * 
     * @param values
     * @return optional
     * @throws IllegalArgumentException if more than one value exist
     */
    public static <T> Optional<T> noneOrOne(Iterator<T> iterator) {
        Optional<T> ret = intNoneOrOne(iterator);
        Preconditions.checkArgument(iterator.hasNext() == false, "contains more than one");
        return ret;
    }

    /**
     * gives none if empty, one if one element, fails if more than one
     * 
     * @param values
     * @return optional
     * @throws IllegalArgumentException if more than one value exist
     */
    public static <T> Optional<T> noneOrOne(Iterable<T> values) {
        Preconditions.checkNotNull(values, "values is null");
        return noneOrOne(values.iterator());
    }

    /**
     * @see Iterables#any(Iterable, Predicate)
     */
    @Deprecated
    public static <T> boolean any(Collection<T> candidates, Predicate<T> condition) {
        return Iterables.any(candidates, condition);
    }

}