org.wildfly.common.iteration.CompositeIterator Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
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/*
* JBoss, Home of Professional Open Source.
* Copyright 2019 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* 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 org.wildfly.common.iteration;
import java.util.Arrays;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.function.Consumer;
/**
* Iterator that iterates over a series of iterators.
* @author Paul Ferraro
*/
public class CompositeIterator implements Iterator {
private final Iterable> iterators;
private Iterator lastIterator;
/**
* Constructs a new composite iterator.
* @param iterators a series of iterators
*/
@SafeVarargs
public CompositeIterator(Iterator... iterators) {
this(Arrays.asList(iterators));
}
/**
* Constructs a new composite iterator.
* @param iterators a series of iterators
*/
public CompositeIterator(Iterable> iterators) {
this.iterators = iterators;
}
@Override
public boolean hasNext() {
for (Iterator iterator : this.iterators) {
if (iterator.hasNext()) return true;
}
return false;
}
@Override
public E next() {
for (Iterator iterator : this.iterators) {
if (iterator.hasNext()) {
this.lastIterator = iterator;
return iterator.next();
}
}
throw new NoSuchElementException();
}
@Override
public void remove() {
Iterator iterator = this.lastIterator;
if (iterator == null) {
throw new IllegalStateException();
}
iterator.remove();
}
@Override
public void forEachRemaining(Consumer action) {
for (Iterator iterator : this.iterators) {
while (iterator.hasNext()) {
action.accept(iterator.next());
}
}
}
}