/*
* Copyright (C) 2008 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 com.google.common.collect;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.annotations.GwtCompatible;
/**
* Precondition checks useful in collection implementations.
*/
@GwtCompatible
final class CollectPreconditions {
static void checkEntryNotNull(Object key, Object value) {
if (key == null) {
throw new NullPointerException("null key in entry: null=" + value);
} else if (value == null) {
throw new NullPointerException("null value in entry: " + key + "=null");
}
}
static int checkNonnegative(int value, String name) {
if (value < 0) {
throw new IllegalArgumentException(name + " cannot be negative but was: " + value);
}
return value;
}
/**
* Precondition tester for {@code Iterator.remove()} that throws an exception with a consistent
* error message.
*/
static void checkRemove(boolean canRemove) {
checkState(canRemove, "no calls to next() since the last call to remove()");
}
}