package io.github.benas.unixstream.components;
import io.github.benas.unixstream.Stage;
import java.util.stream.Stream;
/**
* Keep the first X elements from a stream.
* This is an alias for {@link Stream#limit(long)}.
*
* @param <T> the type of elements in the stream
* @author Mahmoud Ben Hassine ([email protected])
*/
public class Head<T> implements Stage<T, T> {
public static long DEFAULT_SIZE = 10;
private long size;
/**
* Create a new {@link Head} instance.
*/
public Head() {
this(DEFAULT_SIZE);
}
/**
* Create a new {@link Head} instance.
*
* @param size the number of elements to keep
*/
public Head(final long size) {
if (size < 1) {
throw new IllegalArgumentException("Size must be >= 1");
}
this.size = size;
}
/**
* Create a new {@link Head} instance.
*
* @param <T> the type of elements in the stream
* @return a new {@link Head} instance.
*/
public static <T> Head<T> head() {
return new Head<>();
}
/**
* Create a new {@link Head} instance.
*
* @param size the number of elements to keep
* @param <T> the type of elements in the stream
* @return a new {@link Head} instance.
*/
public static <T> Head<T> head(final long size) {
return new Head<>(size);
}
@Override
public Stream<T> apply(Stream<T> input) {
return input.limit(size);
}
}
