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A general and simple library for Android
/*
* Copyright (C) 2016, 2017, 2018, 2019 HaiYang Li
*
* 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.landawn.abacus.util.stream;
import java.util.Iterator;
import java.util.NoSuchElementException;
import com.landawn.abacus.annotation.Internal;
import com.landawn.abacus.util.LongIterator;
import com.landawn.abacus.util.LongList;
import com.landawn.abacus.util.N;
import com.landawn.abacus.util.function.Supplier;
/**
*
*/
@Internal
public abstract class LongIteratorEx extends LongIterator implements IteratorEx {
public static final LongIteratorEx EMPTY = new LongIteratorEx() {
@Override
public boolean hasNext() {
return false;
}
@Override
public long nextLong() {
throw new NoSuchElementException();
}
@Override
public void skip(long n) {
// Do nothing.
}
@Override
public long count() {
return 0;
}
@Override
public long[] toArray() {
return N.EMPTY_LONG_ARRAY;
}
@Override
public void close() {
// Do nothing.
}
};
public static LongIteratorEx empty() {
return EMPTY;
}
@SafeVarargs
public static LongIteratorEx of(final long... a) {
return N.isNullOrEmpty(a) ? EMPTY : of(a, 0, a.length);
}
public static LongIteratorEx of(final long[] a, final int fromIndex, final int toIndex) {
N.checkFromToIndex(fromIndex, toIndex, N.len(a));
if (fromIndex == toIndex) {
return EMPTY;
}
return new LongIteratorEx() {
private int cursor = fromIndex;
@Override
public boolean hasNext() {
return cursor < toIndex;
}
@Override
public long nextLong() {
if (cursor >= toIndex) {
throw new NoSuchElementException();
}
return a[cursor++];
}
@Override
public void skip(long n) {
N.checkArgNotNegative(n, "n");
cursor = n < toIndex - cursor ? cursor + (int) n : toIndex;
}
@Override
public long count() {
return toIndex - cursor;
}
@Override
public long[] toArray() {
return N.copyOfRange(a, cursor, toIndex);
}
@Override
public LongList toList() {
return LongList.of(N.copyOfRange(a, cursor, toIndex));
}
@Override
public void close() {
// Do nothing.
}
};
}
public static LongIteratorEx of(final LongIterator iter) {
if (iter == null) {
return empty();
} else if (iter instanceof LongIteratorEx) {
return ((LongIteratorEx) iter);
}
return new LongIteratorEx() {
@Override
public boolean hasNext() {
return iter.hasNext();
}
@Override
public long nextLong() {
return iter.nextLong();
}
@Override
public void close() {
// Do nothing.
}
};
}
/**
* Lazy evaluation.
*
* @param iteratorSupplier
* @return
*/
public static LongIteratorEx of(final Supplier iteratorSupplier) {
N.checkArgNotNull(iteratorSupplier, "iteratorSupplier");
return new LongIteratorEx() {
private LongIterator iter = null;
private LongIteratorEx iterEx = null;
private boolean isInitialized = false;
@Override
public boolean hasNext() {
if (isInitialized == false) {
init();
}
return iter.hasNext();
}
@Override
public long nextLong() {
if (isInitialized == false) {
init();
}
return iter.nextLong();
}
@Override
public void skip(long n) {
N.checkArgNotNegative(n, "n");
if (isInitialized == false) {
init();
}
if (iterEx != null) {
iterEx.skip(n);
} else {
super.skip(n);
}
}
@Override
public long count() {
if (isInitialized == false) {
init();
}
if (iterEx != null) {
return iterEx.count();
} else {
return super.count();
}
}
@Override
public void close() {
if (isInitialized == false) {
init();
}
if (iterEx != null) {
iterEx.close();
}
}
private void init() {
if (isInitialized == false) {
isInitialized = true;
iter = iteratorSupplier.get();
iterEx = iter instanceof LongIteratorEx ? (LongIteratorEx) iter : null;
}
}
};
}
/**
* Lazy evaluation.
*
* @param arraySupplier
* @return
*/
public static LongIteratorEx oF(final Supplier arraySupplier) {
N.checkArgNotNull(arraySupplier, "arraySupplier");
return new LongIteratorEx() {
private LongIteratorEx iterEx = null;
private boolean isInitialized = false;
@Override
public boolean hasNext() {
if (isInitialized == false) {
init();
}
return iterEx.hasNext();
}
@Override
public long nextLong() {
if (isInitialized == false) {
init();
}
return iterEx.nextLong();
}
@Override
public void skip(long n) {
N.checkArgNotNegative(n, "n");
if (isInitialized == false) {
init();
}
iterEx.skip(n);
}
@Override
public long count() {
if (isInitialized == false) {
init();
}
return iterEx.count();
}
private void init() {
if (isInitialized == false) {
isInitialized = true;
long[] aar = arraySupplier.get();
iterEx = LongIteratorEx.of(aar);
}
}
};
}
public static LongIteratorEx from(final Iterator iter) {
if (iter == null) {
return empty();
} else if (iter instanceof ObjIteratorEx) {
final ObjIteratorEx iteratorEx = ((ObjIteratorEx) iter);
return new LongIteratorEx() {
@Override
public boolean hasNext() {
return iteratorEx.hasNext();
}
@Override
public long nextLong() {
return iteratorEx.next();
}
@Override
public void skip(long n) {
N.checkArgNotNegative(n, "n");
iteratorEx.skip(n);
}
@Override
public long count() {
return iteratorEx.count();
}
@Override
public void close() {
iteratorEx.close();
}
};
} else {
return new LongIteratorEx() {
@Override
public boolean hasNext() {
return iter.hasNext();
}
@Override
public long nextLong() {
return iter.next();
}
@Override
public void close() {
// Do nothing.
}
};
}
}
@Override
public void skip(long n) {
N.checkArgNotNegative(n, "n");
while (n > 0 && hasNext()) {
nextLong();
n--;
}
}
@Override
public long count() {
long result = 0;
while (hasNext()) {
nextLong();
result++;
}
return result;
}
@Override
public void close() {
// Do nothing.
}
}