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Ponzu is a collections framework for Java. It has JDK-compatible List, Set and Map implementations with a rich API and set of utility classes that work with any JDK compatible Collections, Arrays, Maps or Strings.

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/*
 * Copyright 2011 Goldman Sachs.
 *
 * 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.webguys.ponzu.api;

import java.util.Collection;

import com.webguys.ponzu.api.block.function.Function;
import com.webguys.ponzu.api.block.predicate.Predicate;
import com.webguys.ponzu.api.tuple.Pair;

/**
 * Any methods that do not return a LazyIterable when called will cause evaluation to be forced.
 * A LazyIterable is RichIterable which will defer evaluation for certain methods like filte, filterNot, transform, etc.
 *
 * @since 1.0
 */
public interface LazyIterable
        extends RichIterable
{
    /**
     * Creates a deferred iterable for filtering elements from the current iterable.
     */
    LazyIterable filter(Predicate predicate);

    /**
     * Creates a deferred iterable for filtering out elements from the current iterable.
     */
    LazyIterable filterNot(Predicate predicate);

    /**
     * Creates a deferred iterable for collecting elements from the current iterable.
     */
     LazyIterable transform(Function function);

    /**
     * Creates a deferred iterable for filtering and transforming elements from the current iterable.
     */
     LazyIterable transformIf(Predicate predicate, Function function);

    /**
     * Creates a deferred take iterable for the current iterable using the specified count as the limit.
     */
    LazyIterable take(int count);

    /**
     * Creates a deferred drop iterable for the current iterable using the specified count as the limit.
     */
    LazyIterable drop(int count);

    /**
     * Creates a deferred flattening iterable for the current iterable.
     */
     LazyIterable flatTransform(Function> function);

    /**
     * Creates a deferred iterable that will join this iterable with the specified iterable.
     */
    LazyIterable concatenate(Iterable iterable);

    /**
     * Creates a deferred zip iterable.
     */
     LazyIterable> zip(Iterable that);

    /**
     * Creates a deferred zipWithIndex iterable.
     */
    LazyIterable> zipWithIndex();

    /**
     * Creates a deferred chunking iterable.
     */
    LazyIterable> chunk(int size);

    /**
     * Iterates over this iterable adding all elements into the target collection.
     */
    > R into(R target);
}