jetbrains.exodus.CompoundByteIteratorBase Maven / Gradle / Ivy
/**
* Copyright 2010 - 2022 JetBrains s.r.o.
*
* 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
*
* https://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 jetbrains.exodus;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
/**
* Base iterator for {@link CompoundByteIterable}.
*/
public abstract class CompoundByteIteratorBase extends ByteIterator {
@Nullable
private ByteIterator current;
protected CompoundByteIteratorBase(@NotNull ByteIterator current) {
this.current = current;
}
protected CompoundByteIteratorBase() {
this(ByteIterable.EMPTY_ITERATOR);
}
@Override
public boolean hasNext() {
if (current == null) {
return false;
}
if (current.hasNext()) {
return true;
}
current = nextIterator();
return hasNext();
}
@Override
public long skip(final long length) {
long skipped = 0;
while (current != null) {
skipped += current.skip(length - skipped);
if (skipped >= length || !hasNext()) {
break;
}
}
return skipped;
}
@Override
public byte next() {
hasNext();
//noinspection ConstantConditions
return current.next();
}
@NotNull
protected ByteIterator getCurrent() {
if (current == null) {
throw new ExodusException("Can't get current ByteIterator, hasNext() == false");
}
return current;
}
/**
* @return null to finish.
*/
protected abstract ByteIterator nextIterator();
}