Join.java

/*
 * Created on Feb 6, 2011
 * 
 * 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.
 * 
 * Copyright @2011 the original author or authors.
 */
package org.fest.assertions.condition;

import static java.util.Collections.unmodifiableCollection;

import java.util.*;

import org.fest.assertions.core.Matcher;
import org.fest.util.VisibleForTesting;

/**
 * Join of two or more <code>{@link Matcher}</code>s.
 * @param <T> the type of object this condition accepts.
 * 
 * @author Yvonne Wang
 * @author Mikhail Mazursky
 */
public abstract class Join<T> extends Matcher<T> {

  @VisibleForTesting
  final Collection<Matcher<? super T>> conditions;

  /**
   * Creates a new </code>{@link Join}</code>.
   * @param conditions the conditions to join.
   * @throws NullPointerException if the given array is {@code null}.
   * @throws NullPointerException if any of the elements in the given array is {@code null}.
   */
  protected Join(Matcher<? super T>... conditions) {
    if (conditions == null) throw conditionsIsNull();
    this.conditions = new ArrayList<Matcher<? super T>>();
    for (Matcher<? super T> condition : conditions)
      this.conditions.add(notNull(condition));
  }

  /**
   * Creates a new </code>{@link Join}</code>.
   * @param conditions the conditions to join.
   * @throws NullPointerException if the given iterable is {@code null}.
   * @throws NullPointerException if any of the elements in the given iterable is {@code null}.
   */
  protected Join(Iterable<? extends Matcher<? super T>> conditions) {
    if (conditions == null) throw conditionsIsNull();
    this.conditions = new ArrayList<Matcher<? super T>>();
    for (Matcher<? super T> condition : conditions)
      this.conditions.add(notNull(condition));
  }

  private static NullPointerException conditionsIsNull() {
    return new NullPointerException("The given conditions should not be null");
  }

  private static <T> Matcher<T> notNull(Matcher<T> condition) {
    if (condition == null) throw new NullPointerException("The given conditions should not have null entries");
    return condition;
  }

  /**
   * Returns the conditions to join.
   * @return the conditions to join.
   */
  protected final Collection<Matcher<? super T>> conditions() {
    return unmodifiableCollection(conditions);
  }
}