package org.apache.myfaces.tobago.internal.context;
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
*/
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.myfaces.tobago.internal.util.FastStringWriter;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
/**
* In some cases the rendered output must be places in the Response in a different order than it was rendered.
* The <code>ResponseWriterDivider</code> helps to manage a list of buffers which holds the temporary output.
*/
public class ResponseWriterDivider {
private static final Logger LOG = LoggerFactory.getLogger(ResponseWriterDivider.class);
private List<ResponseWriter> writers;
private List<FastStringWriter> buffers;
private ResponseWriter original;
private int current;
private String nameInRequest;
public static ResponseWriterDivider getInstance(FacesContext facesContext, String nameInRequest) {
final Map<String, Object> map = facesContext.getExternalContext().getRequestMap();
ResponseWriterDivider divider = (ResponseWriterDivider) map.get(nameInRequest);
if (divider == null) {
divider = new ResponseWriterDivider(facesContext);
map.put(nameInRequest, divider);
divider.nameInRequest = nameInRequest;
}
return divider;
}
private ResponseWriterDivider(FacesContext facesContext) {
writers = new ArrayList<ResponseWriter>();
buffers = new ArrayList<FastStringWriter>();
current = -1;
original = facesContext.getResponseWriter();
}
/**
* Create (if needed) and activate a new branch.
* After this call, all output will be stored in this new branch.
* <p>
* It is usually needed to get the response writer again with HtmlRendererUtils.getTobagoResponseWriter();
* @return true if the branch was not created new. So the branch was already existent.
*/
public boolean activateBranch(FacesContext facesContext) {
assert writers.size() == buffers.size();
boolean created = true;
current++;
if (writers.size() == current) {
FastStringWriter buffer = new FastStringWriter();
buffers.add(buffer);
ResponseWriter newWriter = facesContext.getResponseWriter().cloneWithWriter(buffer);
writers.add(newWriter);
created = false;
}
facesContext.setResponseWriter(writers.get(current));
if (LOG.isDebugEnabled()) {
LOG.debug(this.toString());
}
return created;
}
/**
* Passivate the current branch.
* After this call, all output will be written in the former branch (if any) or into the original writer.
* <p>
* It is usually needed to get the response writer again with HtmlRendererUtils.getTobagoResponseWriter();
* @return true, if the current writer is not the original writer. So the "stack" is at the bottom.
*/
public boolean passivateBranch(FacesContext facesContext) {
assert writers.size() == buffers.size();
current--;
if (current >= 0) {
facesContext.setResponseWriter(writers.get(current));
if (LOG.isDebugEnabled()) {
LOG.debug(this.toString());
}
return true;
} else {
facesContext.setResponseWriter(original);
if (LOG.isDebugEnabled()) {
LOG.debug(this.toString());
}
return false;
}
}
/**
* Write the collected stuff in the original writer.
* This is always the last call on this object.
*/
public void writeOutAndCleanUp(FacesContext facesContext) throws IOException {
facesContext.setResponseWriter(original);
for (FastStringWriter buffer : buffers) {
original.write(buffer.toString());
}
// clean up.
final Map<String, Object> map = facesContext.getExternalContext().getRequestMap();
map.remove(nameInRequest);
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append("StringBuilder("+System.identityHashCode(this)+") current=" + current + "\n");
int i = 0;
for (FastStringWriter buffer : buffers) {
builder.append("\n- buffer "+ i++ +" ------------------------------------------------------------\n");
builder.append(buffer.toString());
}
builder.append("\n-----------------------------------------------------------------------\n");
return builder.toString();
}
}