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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):
* 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;
import com.google.errorprone.annotations.CheckReturnValue;
import java.util.function.BiPredicate;
import org.jspecify.nullness.Nullable;
/** A minimal interface for null-hostile, persistent immutable maps. */
public interface PMap {
/** Returns whether this map is empty. */
@CheckReturnValue
boolean isEmpty();
/** Returns an iterable for the values in this map. */
@CheckReturnValue
Iterable values();
/** Returns an iterable for the keys in this map. */
@CheckReturnValue
Iterable keys();
/** Retrieves the given key from the map, or returns null if it is not present. */
@Nullable V get(K key);
/**
* Returns a new map with the given key-value pair added. If the value is already present, then
* this same map will be returned.
*/
@CheckReturnValue
PMap plus(K key, V value);
/**
* Returns a new map with the given key removed. If the key was not present in the first place,
* then this same map will be returned.
*/
@CheckReturnValue
PMap minus(K key);
/**
* Performs a reconcile operation to merge {@code this} and {@code that}.
*
* {@code joiner} is called for each pair of entries, one from each map, which share the same
* key and whose values are not {@link Object#equals}. This includes entries that are absent from
* one of the maps, for which {@code null} is passed as the absent value.
*
*
The return of calling {@code joiner} will appear in the merged map at the key of the
* original entry pair. The return may not be null. If the values in a pair of entries are {@link
* Object#equals}, that value will be used directly in the result without calling {@code joiner}.
*
*
The first value passed to {@code joiner} comes from {@code this}, and the second value comes
* from {@code that}. There are no guarantees on the source of {@code key}. Note that {@code that}
* map must be the same implementation.
*/
@CheckReturnValue
PMap reconcile(PMap that, Reconciler joiner);
/**
* Checks equality recursively based on the given equivalence. Short-circuits as soon as a 'false'
* result is found, or if a key in one map is missing from the other. The equivalence will only be
* called on two non-null values. Note that {@code that} map must be the same implementation. Note
* that the equivalence MUST be reflective (i.e. equivalence.test(x, x) == true).
*/
@CheckReturnValue
boolean equivalent(PMap that, BiPredicate equivalence);
/** See {@link #reconcile}. */
@FunctionalInterface
public interface Reconciler {
V merge(K key, @Nullable V thisVal, @Nullable V thatVal);
}
}