com.google.common.collect.ForwardingIterator Maven / Gradle / Ivy
/*
* Copyright (C) 2007 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 com.google.common.annotations.GwtCompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Iterator;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* An iterator which forwards all its method calls to another iterator. Subclasses should override
* one or more methods to modify the behavior of the backing iterator as desired per the decorator pattern.
*
* {@code default} method warning: This class forwards calls to only some {@code
* default} methods. Specifically, it forwards calls only for methods that existed before {@code default}
* methods were introduced. For newer methods, like {@code forEachRemaining}, it inherits their
* default implementations. When those implementations invoke methods, they invoke methods on the
* {@code ForwardingIterator}.
*
* @author Kevin Bourrillion
* @since 2.0
*/
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class ForwardingIterator extends ForwardingObject
implements Iterator {
/** Constructor for use by subclasses. */
protected ForwardingIterator() {}
@Override
protected abstract Iterator delegate();
@Override
public boolean hasNext() {
return delegate().hasNext();
}
@CanIgnoreReturnValue
@Override
@ParametricNullness
public T next() {
return delegate().next();
}
@Override
public void remove() {
delegate().remove();
}
}