/*
 * Copyright (c) 2021 Goldman Sachs and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v. 1.0 which accompany this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 */

package org.eclipse.collections.api;

import java.util.Collection;

import org.eclipse.collections.api.block.function.Function;
import org.eclipse.collections.api.block.function.Function2;
import org.eclipse.collections.api.block.function.primitive.BooleanFunction;
import org.eclipse.collections.api.block.function.primitive.ByteFunction;
import org.eclipse.collections.api.block.function.primitive.CharFunction;
import org.eclipse.collections.api.block.function.primitive.DoubleFunction;
import org.eclipse.collections.api.block.function.primitive.FloatFunction;
import org.eclipse.collections.api.block.function.primitive.IntFunction;
import org.eclipse.collections.api.block.function.primitive.LongFunction;
import org.eclipse.collections.api.block.function.primitive.ShortFunction;
import org.eclipse.collections.api.block.predicate.Predicate;
import org.eclipse.collections.api.block.predicate.Predicate2;
import org.eclipse.collections.api.block.procedure.Procedure;
import org.eclipse.collections.api.ordered.OrderedIterable;
import org.eclipse.collections.api.tuple.Pair;

A LazyIterable is RichIterable which will defer evaluation for certain methods like select, reject, collect, etc. Any methods that do not return a LazyIterable when called will cause evaluation to be forced.
Since:1.0
/** * A LazyIterable is RichIterable which will defer evaluation for certain methods like select, reject, collect, etc. * Any methods that do not return a LazyIterable when called will cause evaluation to be forced. * * @since 1.0 */
public interface LazyIterable<T> extends RichIterable<T> { @Override T getFirst();
Creates a deferred iterable for selecting elements from the current iterable.
/** * Creates a deferred iterable for selecting elements from the current iterable. */
@Override LazyIterable<T> select(Predicate<? super T> predicate); @Override <P> LazyIterable<T> selectWith(Predicate2<? super T, ? super P> predicate, P parameter); @Override <S> LazyIterable<S> selectInstancesOf(Class<S> clazz);
Creates a deferred iterable for rejecting elements from the current iterable.
/** * Creates a deferred iterable for rejecting elements from the current iterable. */
@Override LazyIterable<T> reject(Predicate<? super T> predicate); @Override <P> LazyIterable<T> rejectWith(Predicate2<? super T, ? super P> predicate, P parameter);
Creates a deferred iterable for collecting elements from the current iterable.
/** * Creates a deferred iterable for collecting elements from the current iterable. */
@Override <V> LazyIterable<V> collect(Function<? super T, ? extends V> function); @Override <P, V> LazyIterable<V> collectWith(Function2<? super T, ? super P, ? extends V> function, P parameter);
Creates a deferred iterable for selecting and collecting elements from the current iterable.
/** * Creates a deferred iterable for selecting and collecting elements from the current iterable. */
@Override <V> LazyIterable<V> collectIf(Predicate<? super T> predicate, Function<? super T, ? extends V> function);
Creates a deferred take iterable for the current iterable using the specified count as the limit.
/** * Creates a deferred take iterable for the current iterable using the specified count as the limit. */
LazyIterable<T> take(int count);
Creates a deferred drop iterable for the current iterable using the specified count as the limit.
/** * Creates a deferred drop iterable for the current iterable using the specified count as the limit. */
LazyIterable<T> drop(int count);
See Also:
  • takeWhile.takeWhile(Predicate)
Since:8.0
/** * @see OrderedIterable#takeWhile(Predicate) * @since 8.0 */
LazyIterable<T> takeWhile(Predicate<? super T> predicate);
See Also:
  • dropWhile.dropWhile(Predicate)
Since:8.0
/** * @see OrderedIterable#dropWhile(Predicate) * @since 8.0 */
LazyIterable<T> dropWhile(Predicate<? super T> predicate);
Creates a deferred distinct iterable to get distinct elements from the current iterable.
Since:5.0
/** * Creates a deferred distinct iterable to get distinct elements from the current iterable. * * @since 5.0 */
LazyIterable<T> distinct();
Creates a deferred flattening iterable for the current iterable.
/** * Creates a deferred flattening iterable for the current iterable. */
@Override <V> LazyIterable<V> flatCollect(Function<? super T, ? extends Iterable<V>> function);
Since:9.2
/** * @since 9.2 */
@Override default <P, V> LazyIterable<V> flatCollectWith(Function2<? super T, ? super P, ? extends Iterable<V>> function, P parameter) { return this.flatCollect(each -> function.apply(each, parameter)); }
Creates a deferred iterable that will join this iterable with the specified iterable.
/** * Creates a deferred iterable that will join this iterable with the specified iterable. */
LazyIterable<T> concatenate(Iterable<T> iterable);
Creates a deferred zip iterable.
/** * Creates a deferred zip iterable. */
@Override <S> LazyIterable<Pair<T, S>> zip(Iterable<S> that);
Creates a deferred zipWithIndex iterable.
/** * Creates a deferred zipWithIndex iterable. */
@Override LazyIterable<Pair<T, Integer>> zipWithIndex();
Creates a deferred chunk iterable.
/** * Creates a deferred chunk iterable. */
@Override LazyIterable<RichIterable<T>> chunk(int size);
Creates a deferred tap iterable.
/** * Creates a deferred tap iterable. */
@Override LazyIterable<T> tap(Procedure<? super T> procedure);
Iterates over this iterable adding all elements into the target collection.
/** * Iterates over this iterable adding all elements into the target collection. */
@Override <R extends Collection<T>> R into(R target);
Returns a lazy BooleanIterable which will transform the underlying iterable data to boolean values based on the booleanFunction.
/** * Returns a lazy BooleanIterable which will transform the underlying iterable data to boolean values based on the booleanFunction. */
@Override LazyBooleanIterable collectBoolean(BooleanFunction<? super T> booleanFunction);
Returns a lazy ByteIterable which will transform the underlying iterable data to byte values based on the byteFunction.
/** * Returns a lazy ByteIterable which will transform the underlying iterable data to byte values based on the byteFunction. */
@Override LazyByteIterable collectByte(ByteFunction<? super T> byteFunction);
Returns a lazy CharIterable which will transform the underlying iterable data to char values based on the charFunction.
/** * Returns a lazy CharIterable which will transform the underlying iterable data to char values based on the charFunction. */
@Override LazyCharIterable collectChar(CharFunction<? super T> charFunction);
Returns a lazy DoubleIterable which will transform the underlying iterable data to double values based on the doubleFunction.
/** * Returns a lazy DoubleIterable which will transform the underlying iterable data to double values based on the doubleFunction. */
@Override LazyDoubleIterable collectDouble(DoubleFunction<? super T> doubleFunction);
Returns a lazy FloatIterable which will transform the underlying iterable data to float values based on the floatFunction.
/** * Returns a lazy FloatIterable which will transform the underlying iterable data to float values based on the floatFunction. */
@Override LazyFloatIterable collectFloat(FloatFunction<? super T> floatFunction);
Returns a lazy IntIterable which will transform the underlying iterable data to int values based on the intFunction.
/** * Returns a lazy IntIterable which will transform the underlying iterable data to int values based on the intFunction. */
@Override LazyIntIterable collectInt(IntFunction<? super T> intFunction);
Returns a lazy LongIterable which will transform the underlying iterable data to long values based on the longFunction.
/** * Returns a lazy LongIterable which will transform the underlying iterable data to long values based on the longFunction. */
@Override LazyLongIterable collectLong(LongFunction<? super T> longFunction);
Returns a lazy ShortIterable which will transform the underlying iterable data to short values based on the shortFunction.
/** * Returns a lazy ShortIterable which will transform the underlying iterable data to short values based on the shortFunction. */
@Override LazyShortIterable collectShort(ShortFunction<? super T> shortFunction); }