jetbrains.exodus.CompoundByteIterable 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;
/**
* A compound {@link ByteIterable} that can be composed of several sub-iterables.
*/
public class CompoundByteIterable extends ByteIterableBase {
private final ByteIterable[] iterables;
private final int count;
public CompoundByteIterable(ByteIterable[] iterables) {
this(iterables, iterables.length);
}
public CompoundByteIterable(ByteIterable[] iterables, int count) {
if (count < 1) {
throw new ExodusException("Failed to initialize CompoundByteIterable");
}
this.iterables = iterables;
this.count = count;
}
@Override
public int getLength() {
int result = length;
if (result == -1) {
result = 0;
for (int i = 0; i < count; ++i) {
result += iterables[i].getLength();
}
length = result;
}
return result;
}
@Override
protected ByteIterator getIterator() {
return new CompoundByteIteratorBase(iterables[0].iterator()) {
int off = 0;
@Override
public ByteIterator nextIterator() {
off++;
return off < count ? iterables[off].iterator() : null;
}
};
}
}