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Closure Compiler is a JavaScript optimizing compiler. It parses your JavaScript, analyzes it, removes dead code and rewrites and minimizes what's left. It also checks syntax, variable references, and types, and warns about common JavaScript pitfalls. It is used in many of Google's JavaScript apps, including Gmail, Google Web Search, Google Maps, and Google Docs.

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/*
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Rhino code, released
 * May 6, 1999.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1997-1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Bob Jervis
 *   Google Inc.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License Version 2 or later (the "GPL"), in which
 * case the provisions of the GPL are applicable instead of those above. If
 * you wish to allow use of your version of this file only under the terms of
 * the GPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replacing
 * them with the notice and other provisions required by the GPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the GPL.
 *
 * ***** END LICENSE BLOCK ***** */

package com.google.javascript.rhino.jstype;

import com.google.common.collect.ImmutableList;
import java.util.function.Function;
import java.util.function.Predicate;

/**
 * {@code Stream}-like functions for efficient querying of collections of {@code JSType}s.
 *
 * These methods are designed to minimize allocations since they are expected to be called
 * very often. That's why they don't:
 *
 * 

 *   instantiate {@link Iterator}s
 *   
instantiate {@link Stream}s
 *   
(un)box primitives
 *   
expect closure-generating lambdas
 * 
 */
final class JSTypeIterations {

  /** @return whether any element of {@code types} matches {@code predicate}. */
  static boolean anyTypeMatches(
      Predicate predicate, ImmutableList types) {
    for (int i = 0; i < types.size(); i++) {
      if (predicate.test(types.get(i))) {
        return true;
      }
    }
    return false;
  }

  /** @return whether any element of {@code union} matches {@code predicate}. */
  static boolean anyTypeMatches(Predicate predicate, UnionType union) {
    return anyTypeMatches(predicate, union.getAlternates());
  }

  /** @return whether all elements of {@code types} match {@code predicate}. */
  static boolean allTypesMatch(
      Predicate predicate, ImmutableList types) {
    for (int i = 0; i < types.size(); i++) {
      if (!predicate.test(types.get(i))) {
        return false;
      }
    }
    return true;
  }

  /** @return whether all elements of {@code union} match {@code predicate}. */
  static boolean allTypesMatch(Predicate predicate, UnionType union) {
    return allTypesMatch(predicate, union.getAlternates());
  }

  /** @return the result of applying {@code mapper} to all elements of {@code types}. */
  static  ImmutableList mapTypes(
      Function mapper, ImmutableList types) {
    ImmutableList.Builder builder = ImmutableList.builder();
    for (int i = 0; i < types.size(); i++) {
      builder.add(mapper.apply(types.get(i)));
    }
    return builder.build();
  }

  /** @return the union of applying {@code mapper} to all elements of {@code types}. */
  static JSType mapTypes(Function mapper, UnionType union) {
    return UnionType.builder(union.registry)
        .addAlternates(mapTypes(mapper, union.getAlternates()))
        .build();
  }

  private JSTypeIterations() {
    // Not instantiable.
  }
}