001// Copyright 2010 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007// http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.func;
016
017/**
018 * The result of the evaluation of a {@link LazyFunction}.
019 * 
020 * @since 5.2.0
021 */
022public class LazyContinuation<T>
023{
024    private final LazyValue<T> nextValue;
025
026    private final LazyFunction<T> nextFunction;
027
028    public LazyContinuation(T nextValue, LazyFunction<T> nextFunction)
029    {
030        this(new StaticValue<T>(nextValue), nextFunction);
031    }
032
033    public LazyContinuation(LazyValue<T> nextValue, LazyFunction<T> nextFunction)
034    {
035        assert nextValue != null;
036        assert nextFunction != null;
037
038        this.nextValue = nextValue;
039        this.nextFunction = nextFunction;
040    }
041
042    /**
043     * Returns, indirectly, the next value computed by the lazy function. The LazyValue represents
044     * a deferred computation.
045     */
046    public LazyValue<T> nextValue()
047    {
048        return nextValue;
049    }
050
051    /** Returns a new lazy function that will return the next continuation. */
052    public LazyFunction<T> nextFunction()
053    {
054        return nextFunction;
055    }
056
057}