| // Copyright 2011 The Apache Software Foundation |
| // |
| // 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 org.apache.tapestry5.func; |
| |
| import java.util.List; |
| |
| class Interleaver<T> implements LazyFunction<T> |
| { |
| private final int valueIndex; |
| |
| private final List<Flow<T>> flows; |
| |
| Interleaver(List<Flow<T>> flows) |
| { |
| this(flows, 0); |
| } |
| |
| private Interleaver(List<Flow<T>> flows, int valueIndex) |
| { |
| this.flows = flows; |
| this.valueIndex = valueIndex; |
| } |
| |
| @Override |
| public LazyContinuation<T> next() |
| { |
| if (valueIndex == 0) |
| { |
| for (Flow<T> flow : flows) |
| { |
| if (flow.isEmpty()) |
| return null; |
| } |
| |
| } |
| |
| return new LazyContinuation<T>(flows.get(valueIndex).first(), nextFunction()); |
| } |
| |
| private LazyFunction<T> nextFunction() |
| { |
| if (valueIndex < flows.size() - 1) { return new Interleaver<T>(flows, valueIndex + 1); } |
| |
| List<Flow<T>> nextFlows = F.flow(flows).map(new Mapper<Flow<T>, Flow<T>>() |
| { |
| @Override |
| public Flow<T> map(Flow<T> element) |
| { |
| return element.rest(); |
| } |
| }).toList(); |
| |
| return new Interleaver<T>(nextFlows, 0); |
| } |
| |
| } |