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package com.sun.faces.application.view;
import java.io.Writer;
import java.io.IOException;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.application.StateManager;
import com.sun.faces.RIConstants;
import com.sun.faces.util.Util;
import com.sun.faces.io.FastStringWriter;
/**
* Custom {@link Writer} to efficiently handle the state manager replacement
* marker written out by {@link MultiViewHandler#writeState(javax.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<WriteBehindStateWriter> CUR_WRITER =
new ThreadLocal<WriteBehindStateWriter>();
private Writer out;
private Writer orig;
private FastStringWriter fWriter;
private boolean stateWritten;
private int bufSize;
private char[] buf;
private FacesContext context;
// -------------------------------------------------------- Constructors
/**
* Constructs a new <code>WriteBehindStateWriter</code> 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;
this.orig = out;
this.context = context;
this.bufSize = bufSize;
this.buf = new char[bufSize];
CUR_WRITER.set(this);
}
// ------------------------------------------------- Methods from Writer
/**
* Writes directly to the current <code>out</code>.
*
* @see Writer#write(int)
*/
public void write(int c) throws IOException {
out.write(c);
}
/**
* Writes directly to the current <code>out</code>.
*
* @see Writer#write(char[])
*/
public void write(char cbuf[]) throws IOException {
out.write(cbuf);
}
/**
* Writes directly to the current <code>out</code>.
*
* @see Writer#write(String)
*/
public void write(String str) throws IOException {
out.write(str);
}
/**
* Writes directly to the current <code>out</code>.
*
* @see Writer#write(String, int, int)
*/
public void write(String str, int off, int len) throws IOException {
out.write(str, off, len);
}
/**
* Writes directly to the current <code>out</code>.
*
* @see Writer#write(char[], int, int)
*/
public void write(char cbuf[], int off, int len) throws IOException {
out.write(cbuf, off, len);
}
/**
* This is a no-op.
*/
public void flush() throws IOException {
// no-op
}
/**
* This is a no-op.
*/
public void close() throws IOException {
// no-op
}
// ------------------------------------------------------ Public Methods
/**
* @return the <code>WriteBehindStateWriter</code> 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) {
this.stateWritten = true;
out = fWriter = new FastStringWriter(1024);
}
}
/**
* @return <code>true</code> if {@link #writingState()} has been called,
* otherwise returns <code>false</code>
*/
public boolean stateWritten() {
return stateWritten;
}
/**
* <p> Write directly from our FastStringWriter to the provided writer.</p>
*
* @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 begining 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);
} else {
pos = tildeIdx;
tildeIdx = getNextDelimiterIndex(builder,
tildeIdx + 1);
}
}
stateBuilder = getState(stateManager, origWriter);
stateLen = stateBuilder.length();
} 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.
*
* <p>
* In JSF 2.2 it is required by the specification that the view state in
* each h:form has a unique view state id. So we have to call this method
* multiple times as each h:form needs to generate the view state string
* for itself.
* </p>
*
* @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 state =
new FastStringWriter((stateManager.isSavingStateInClient(
context)) ? bufSize : 128);
context.setResponseWriter(origWriter.cloneWithWriter(state));
stateManager.writeState(context, stateManager.saveView(context));
context.setResponseWriter(origWriter);
StringBuilder stateBuilder = state.getBuffer();
return stateBuilder;
}
/**
* @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);
}
}