/**
* Copyright 2008 Google Inc.
*
* 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.waveprotocol.wave.model.wave;
import org.waveprotocol.wave.model.id.WaveId;
import org.waveprotocol.wave.model.id.WaveletId;
/**
* A Wave View is a collection of wavelets within a wave.
*
*/
public interface WaveView {
/**
* Gets the unique identifier of the wave in view.
*
* @return the unique identifier of the wave.
*/
WaveId getWaveId();
/**
* Gets the wavelets in this wave view. The order of iteration is unspecified.
*
* @return wavelets in this wave view.
*/
Iterable<? extends Wavelet> getWavelets();
/**
* Gets a wavelet from the view by id.
*
* @return the requested wavelet, or null if it is not in view.
*/
Wavelet getWavelet(WaveletId waveletId);
/**
* Creates a new wavelet in the wave.
*
* @return a new wavelet.
*/
Wavelet createWavelet();
/**
* Gets some wavelet nominated to be a "root".
*
* @return the root wavelet, if it exists in the view.
*/
Wavelet getRoot();
/**
* Creates a "root" wavelet. Implementations of this interface are free to
* choose what the root wavelet is, as long as it is the same wavelet later
* returned by {@link #getRoot()}.
*
* @return the new wavelet.
*/
Wavelet createRoot();
/**
* Gets the user-data wavelet in this view.
*
* @return the root wavelet, if it exists in the view.
*/
Wavelet getUserData();
/**
* Creates the user-data wavelet.
*
* @return the new wavelet.
* @throws IllegalStateException if the user-data wavelet already exists.
*/
Wavelet createUserData();
}