com.sun.faces.application.view.WriteBehindStateWriter Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of jakarta.faces Show documentation
Show all versions of jakarta.faces Show documentation
EE4J Compatible Implementation for Jakarta Faces API
The newest version!
/*
* Copyright (c) 1997, 2021 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package com.sun.faces.application.view;
import static jakarta.faces.application.StateManager.IS_SAVING_STATE;
import static java.lang.Boolean.TRUE;
import java.io.IOException;
import java.io.Writer;
import java.util.Map;
import com.sun.faces.RIConstants;
import com.sun.faces.io.FastStringWriter;
import com.sun.faces.util.Util;
import jakarta.faces.application.StateManager;
import jakarta.faces.context.FacesContext;
import jakarta.faces.context.ResponseWriter;
import jakarta.faces.view.ViewDeclarationLanguage;
/**
* Custom {@link Writer} to efficiently handle the state manager replacement marker written out by
* {@link MultiViewHandler#writeState(jakarta.faces.context.FacesContext)}.
*/
final class WriteBehindStateWriter extends Writer {
// length of the state marker
private static final int STATE_MARKER_LEN = RIConstants.SAVESTATE_FIELD_MARKER.length();
private static final ThreadLocal CUR_WRITER = new ThreadLocal<>();
private Writer out;
private final Writer orig;
private FastStringWriter fWriter;
private boolean stateWritten;
private final int bufSize;
private final char[] buf;
private final FacesContext context;
private Object state;
// -------------------------------------------------------- Constructors
/**
* Constructs a new WriteBehindStateWriter instance.
*
* @param out the writer we write non-buffered content to
* @param context the {@link FacesContext} for the current request
* @param bufSize the buffer size for post-processing buffered content
*/
public WriteBehindStateWriter(Writer out, FacesContext context, int bufSize) {
this.out = out;
orig = out;
this.context = context;
this.bufSize = bufSize;
buf = new char[bufSize];
CUR_WRITER.set(this);
}
// ------------------------------------------------- Methods from Writer
/**
* Writes directly to the current out.
*
* @see Writer#write(int)
*/
@Override
public void write(int c) throws IOException {
out.write(c);
}
/**
* Writes directly to the current out.
*
* @see Writer#write(char[])
*/
@Override
public void write(char[] cbuf) throws IOException {
out.write(cbuf);
}
/**
* Writes directly to the current out.
*
* @see Writer#write(String)
*/
@Override
public void write(String str) throws IOException {
out.write(str);
}
/**
* Writes directly to the current out.
*
* @see Writer#write(String, int, int)
*/
@Override
public void write(String str, int off, int len) throws IOException {
out.write(str, off, len);
}
/**
* Writes directly to the current out.
*
* @see Writer#write(char[], int, int)
*/
@Override
public void write(char[] cbuf, int off, int len) throws IOException {
out.write(cbuf, off, len);
}
/**
* This is a no-op.
*/
@Override
public void flush() throws IOException {
// no-op
}
/**
* This is a no-op.
*/
@Override
public void close() throws IOException {
// no-op
}
// ------------------------------------------------------ Public Methods
/**
* @return the WriteBehindStateWriter being used for processing this request
*/
public static WriteBehindStateWriter getCurrentInstance() {
return CUR_WRITER.get();
}
/**
* Clear the ThreadLocal state.
*/
public void release() {
CUR_WRITER.remove();
}
/**
* When called, the original writer is backed up and replaced with a new FastStringWriter. All content written after
* this method is called will then be buffered and written out later after the entire view has been rendered.
*/
public void writingState() {
if (!stateWritten) {
stateWritten = true;
out = fWriter = new FastStringWriter(1024);
}
}
/**
* @return true if {@link #writingState()} has been called, otherwise returns false
*/
public boolean stateWritten() {
return stateWritten;
}
/**
*
* Write directly from our FastStringWriter to the provided writer.
*
*
* @throws IOException if an error occurs
*/
public void flushToWriter() throws IOException {
// Save the state to a new instance of StringWriter to
// avoid multiple serialization steps if the view contains
// multiple forms.
StateManager stateManager = Util.getStateManager(context);
ResponseWriter origWriter = context.getResponseWriter();
StringBuilder stateBuilder = getState(stateManager, origWriter);
StringBuilder builder = fWriter.getBuffer();
// Begin writing...
int totalLen = builder.length();
int stateLen = stateBuilder.length();
int pos = 0;
int tildeIdx = getNextDelimiterIndex(builder, pos);
while (pos < totalLen) {
if (tildeIdx != -1) {
if (tildeIdx > pos && tildeIdx - pos > bufSize) {
// There's enough content before the first ~
// to fill the entire buffer
builder.getChars(pos, pos + bufSize, buf, 0);
orig.write(buf);
pos += bufSize;
} else {
// Write all content up to the first '~'
builder.getChars(pos, tildeIdx, buf, 0);
int len = tildeIdx - pos;
orig.write(buf, 0, len);
// Now check to see if the state saving string is
// at the beginning of pos, if so, write our
// state out.
if (builder.indexOf(RIConstants.SAVESTATE_FIELD_MARKER, pos) == tildeIdx) {
// buf is effectively zero'd out at this point
int statePos = 0;
while (statePos < stateLen) {
if (stateLen - statePos > bufSize) {
// enough state to fill the buffer
stateBuilder.getChars(statePos, statePos + bufSize, buf, 0);
orig.write(buf);
statePos += bufSize;
} else {
int slen = stateLen - statePos;
stateBuilder.getChars(statePos, stateLen, buf, 0);
orig.write(buf, 0, slen);
statePos += slen;
}
}
// Push us past the last '~' at the end of the marker
pos += len + STATE_MARKER_LEN;
tildeIdx = getNextDelimiterIndex(builder, pos);
stateBuilder = getState(stateManager, origWriter);
stateLen = stateBuilder.length();
} else {
pos = tildeIdx;
tildeIdx = getNextDelimiterIndex(builder, tildeIdx + 1);
}
}
} else {
// We've written all of the state field markers.
// finish writing content
if (totalLen - pos > bufSize) {
// There's enough content to fill the buffer
builder.getChars(pos, pos + bufSize, buf, 0);
orig.write(buf);
pos += bufSize;
} else {
// We're near the end of the response
builder.getChars(pos, totalLen, buf, 0);
int len = totalLen - pos;
orig.write(buf, 0, len);
pos += len + 1;
}
}
}
// all state has been written. Have 'out' point to the
// response so that all subsequent writes will make it to the
// browser.
out = orig;
}
/**
* Get the state.
*
*
* In Faces it is required by the specification that the view state hidden input in each h:form has a unique id. So we
* have to call this method multiple times as each h:form needs to generate the element id for itself.
*
*
* @param stateManager the state manager.
* @param origWriter the original response writer.
* @return the state.
* @throws IOException when an I/O error occurs.
*/
private StringBuilder getState(StateManager stateManager, ResponseWriter origWriter) throws IOException {
FastStringWriter stateWriter = new FastStringWriter(stateManager.isSavingStateInClient(context) ? bufSize : 128);
context.setResponseWriter(origWriter.cloneWithWriter(stateWriter));
if (state == null) {
String viewId = context.getViewRoot().getViewId();
ViewDeclarationLanguage vdl = context.getApplication().getViewHandler().getViewDeclarationLanguage(context, viewId);
if (vdl != null) {
Map contextAttributes = context.getAttributes();
try {
contextAttributes.put(IS_SAVING_STATE, TRUE);
state = vdl.getStateManagementStrategy(context, viewId)
.saveView(context);
} finally {
contextAttributes.remove(IS_SAVING_STATE);
}
}
}
stateManager.writeState(context, state);
context.setResponseWriter(origWriter);
return stateWriter.getBuffer();
}
/**
* @param builder buffered content
* @param offset the offset to start the search from
* @return the index of the next delimiter, if any
*/
private static int getNextDelimiterIndex(StringBuilder builder, int offset) {
return builder.indexOf(RIConstants.SAVESTATE_FIELD_DELIMITER, offset);
}
}