org.soulwing.prospecto.runtime.text.AbstractViewWriter Maven / Gradle / Ivy
/*
* File created on Mar 19, 2016
*
* Copyright (c) 2016 Carl Harris, Jr
* and others as noted
*
* 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.soulwing.prospecto.runtime.text;
import java.util.Iterator;
import org.soulwing.prospecto.api.View;
import org.soulwing.prospecto.api.ViewException;
import org.soulwing.prospecto.api.ViewWriter;
import org.soulwing.prospecto.api.options.Options;
import org.soulwing.prospecto.api.options.WriterKeys;
/**
* An object that produces a representation of a view on a specified target.
*
* This class is designed to allow a callback-driven interpretation of a
* view's event stream.
*
* A writer is not thread safe.
*
* @author Carl Harris
*/
public abstract class AbstractViewWriter implements ViewWriter {
private final View view;
private final Options options;
/**
* Constructs a new writer.
* @param view the subject view
* @param options configuration options
*
*/
protected AbstractViewWriter(View view,
Options options) {
this.view = view;
this.options = options;
}
public Options getOptions() {
return options;
}
/**
* Writes the view to the target output stream.
*
* The underlying output stream is not closed by this method.
* @throws ViewException if an error occurs in writing the view.
* @throws IllegalStateException if this method has already been invoked on
* this writer instance
*/
@Override
public final void writeView() throws ViewException {
try {
beforeViewEvents();
final Iterator events = view.iterator();
while (events.hasNext()) {
final View.Event event = events.next();
switch (event.getType()) {
case BEGIN_OBJECT:
onBeginObject(event);
break;
case END_OBJECT:
onEndObject(event);
break;
case BEGIN_ARRAY:
onBeginArray(event);
break;
case END_ARRAY:
onEndArray(event);
break;
case VALUE:
doValue(event);
break;
case META:
onMeta(event);
break;
case DISCRIMINATOR:
onDiscriminator(event);
break;
default:
throw new IllegalStateException("unrecognized event type: "
+ event.getType().name());
}
}
afterViewEvents();
}
catch (ViewException ex) {
throw ex;
}
catch (Exception ex) {
throw new ViewException(ex);
}
}
private void doValue(View.Event event) throws Exception {
if (event.getValue() != null
|| getOptions().isEnabled(WriterKeys.INCLUDE_NULL_PROPERTIES)) {
onValue(event);
}
}
/**
* Notifies the recipient that the view's event stream will start.
*/
protected void beforeViewEvents() throws Exception {
}
/**
* Notifies the recipient that the view's event stream has ended.
* @throws Exception
*/
protected void afterViewEvents() throws Exception {
}
/**
* Notifies the recipient that the next {@code event} is of type
* {@link View.Event.Type#BEGIN_OBJECT}.
* @param event the subject event
* @throws Exception
*/
protected abstract void onBeginObject(View.Event event) throws Exception;
/**
* Notifies the recipient that the next {@code event} is of type
* {@link View.Event.Type#END_OBJECT}.
* @param event the subject event
* @throws Exception
*/
protected abstract void onEndObject(View.Event event) throws Exception;
/**
* Notifies the recipient that the next {@code event} is of type
* {@link View.Event.Type#BEGIN_ARRAY}.
* @param event the subject event
* @throws Exception
*/
protected abstract void onBeginArray(View.Event event) throws Exception;
/**
* Notifies the recipient that the next {@code event} is of type
* {@link View.Event.Type#END_ARRAY}.
* @param event the subject event
* @throws Exception
*/
protected abstract void onEndArray(View.Event event) throws Exception;
/**
* Notifies the recipient that the next {@code event} is of type
* {@link View.Event.Type#VALUE}.
* @param event the subject event
* @throws Exception
*/
protected abstract void onValue(View.Event event) throws Exception;
/**
* Notifies the recipient that the next {@code event} is of type
* {@link View.Event.Type#META}.
* @param event the subject event
* @throws Exception
*/
protected abstract void onMeta(View.Event event) throws Exception;
/**
* Notifies the recipient that the next {@code event} is of type
* {@link View.Event.Type#DISCRIMINATOR}.
* @param event the subject event
* @throws Exception
*/
protected abstract void onDiscriminator(View.Event event) throws Exception;
/**
* Gets the source view for this writer.
* @return source view
*/
protected final View getView() {
return view;
}
}