jakarta.faces.context.ResponseWriter Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2020 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 jakarta.faces.context;
import java.io.IOException;
import java.io.Writer;
import jakarta.faces.component.UIComponent;
/**
*
* ResponseWriter is an abstract class describing an adapter
* to an underlying output mechanism for character-based output. In addition to the low-level write()
* methods inherited from java.io.Writer, this class provides utility methods that are useful in producing
* elements and attributes for markup languages like HTML and XML.
*
*/
public abstract class ResponseWriter extends Writer {
/**
*
* Return the content type (such as "text/html") for this {@link ResponseWriter}. Note: this must not include the
* "charset=" suffix.
*
*
* @return the content type
*/
public abstract String getContentType();
/**
*
* Return the character encoding (such as "ISO-8859-1") for this {@link ResponseWriter}. Please see
* the IANA for a list of character encodings.
*
*
* @return the character encoding
*/
public abstract String getCharacterEncoding();
/**
*
* Flush any ouput buffered by the output method to the underlying Writer or OutputStream. This method will not flush
* the underlying Writer or OutputStream; it simply clears any values buffered by this {@link ResponseWriter}.
*
*/
@Override
public abstract void flush() throws IOException;
/**
*
* Write whatever text should begin a response.
*
*
* @throws IOException if an input/output error occurs
*/
public abstract void startDocument() throws IOException;
/**
*
* Write whatever text should end a response. If there is an open element that has been created by a call to
* startElement(), that element will be closed first.
*
*
* @throws IOException if an input/output error occurs
*/
public abstract void endDocument() throws IOException;
/**
*
* Write the start of an element, up to and including the element name. Once
* this method has been called, clients can call the writeAttribute() or writeURIAttribute()
* methods to add attributes and corresponding values. The starting element will be closed (that is, the trailing '>'
* character added) on any subsequent call to startElement(), writeComment(),
* writeText(), endElement(), endDocument(), close(),
* flush(), or write().
*
*
*
*
*
* If the argument component's pass through attributes includes an attribute of the name given by the value of the
* symbolic constant {@link jakarta.faces.render.Renderer#PASSTHROUGH_RENDERER_LOCALNAME_KEY}, use that as the element
* name, instead of the value passed as the first parameter to this method. Care must be taken so that this value is not
* also rendered when any other pass through attributes on this component are rendered.
*
*
*
*
* @param name Name of the element to be started
*
* @param component The {@link UIComponent} (if any) to which this element corresponds.
* This component is inspected for its pass through attributes as described in the standard HTML_BASIC {@code
* RenderKit} specification.
*
* @throws IOException if an input/output error occurs
* @throws NullPointerException if name is null
*/
public abstract void startElement(String name, UIComponent component) throws IOException;
/**
*
* Write the end of an element, after closing any open element created by a
* call to startElement(). Elements must be closed in the inverse order from which they were opened; it is
* an error to do otherwise.
*
*
*
*
*
* If the argument component's pass through attributes includes an attribute of the name given by the value of the
* symbolic constant {@link jakarta.faces.render.Renderer#PASSTHROUGH_RENDERER_LOCALNAME_KEY}, use that as the element
* name, instead of the value passed as the first parameter to this method.
*
*
*
*
* @param name Name of the element to be ended
* @throws IOException if an input/output error occurs
* @throws NullPointerException if name is null
*/
public abstract void endElement(String name) throws IOException;
/**
*
* Write an attribute name and corresponding value, after converting that text to a String (if necessary), and after
* performing any escaping appropriate for the markup language being rendered. This method may only be called after a
* call to startElement(), and before the opened element has been closed.
*
*
* @param name Attribute name to be added
* @param value Attribute value to be added
* @param property Name of the property or attribute (if any) of the {@link UIComponent} associated with the containing
* element, to which this generated attribute corresponds
* @throws IllegalStateException if this method is called when there is no currently open element
* @throws IOException if an input/output error occurs
* @throws NullPointerException if name is null
*/
public abstract void writeAttribute(String name, Object value, String property) throws IOException;
/**
*
* Write a URI attribute name and corresponding value, after converting that
* text to a String (if necessary), and after performing any encoding or
* escaping appropriate to the markup language being rendered. When rendering
* in a WWW environment, the escaping conventions established in the W3C URI spec document
* <http://www.w3.org/Addressing/URL/uri-spec.html>
* must be followed. In particular, spaces ' ' must be encoded as %20 and not the plus character '+'. This method
* may only be called after a call to startElement(), and before the opened element has been closed.
*
*
* @param name Attribute name to be added
* @param value Attribute value to be added
* @param property Name of the property or attribute (if any) of the {@link UIComponent} associated with the containing
* element, to which this generated attribute corresponds
* @throws IllegalStateException if this method is called when there is no currently open element
* @throws IOException if an input/output error occurs
* @throws NullPointerException if name is null
*/
public abstract void writeURIAttribute(String name, Object value, String property) throws IOException;
/**
*
* Open an XML CDATA block. Note that XML does not allow nested CDATA blocks, though this
* method does not enforce that constraint. The default implementation of this method takes no action when invoked.
*
*
* @throws IOException if input/output error occures
*/
public void startCDATA() throws IOException {
}
/**
*
*
* Close an XML CDATA block. The default implementation of this method takes no action when invoked.
*
*
* @throws IOException if input/output error occures
*/
public void endCDATA() throws IOException {
throw new UnsupportedOperationException();
}
/**
*
* Write a comment containing the specified text, after converting that text to a String (if necessary), and after
* performing any escaping appropriate for the markup language being rendered. If there is an open element that has been
* created by a call to startElement(), that element will be closed first.
*
*
* @param comment Text content of the comment
* @throws IOException if an input/output error occurs
* @throws NullPointerException if comment is null
*/
public abstract void writeComment(Object comment) throws IOException;
/**
*
* Write a string containing the markup specific preamble. No escaping is performed. The default implementation simply
* calls through to {@link #write(java.lang.String)} .
*
*
*
*
*
* The implementation makes no checks if this is the correct place in the response to have a preamble, nor does it
* prevent the preamble from being written more than once.
*
*
*
*
* @since 2.2
* @param preamble Text content of the preamble
* @throws IOException if an input/output error occurs
*/
public void writePreamble(String preamble) throws IOException {
write(preamble);
}
/**
*
* Write a string containing the markup specific doctype. No escaping is performed. The default implementation simply
* calls through to {@link #write(java.lang.String)} .
*
*
*
*
*
* The implementation makes no checks if this is the correct place in the response to have a doctype, nor does it
* prevent the doctype from being written more than once.
*
*
*
*
* @since 2.2
* @param doctype Text content of the doctype
* @throws IOException if an input/output error occurs
*/
public void writeDoctype(String doctype) throws IOException {
write(doctype);
}
/**
*
* Write an object, after converting it to a String (if necessary), and after performing any escaping appropriate for
* the markup language being rendered. If there is an open element that has been created by a call to
* startElement(), that element will be closed first.
*
*
* @param text Text to be written
* @param property Name of the property or attribute (if any) of the {@link UIComponent} associated with the containing
* element, to which this generated text corresponds
* @throws IOException if an input/output error occurs
* @throws NullPointerException if text is null
*/
public abstract void writeText(Object text, String property) throws IOException;
/**
*
* Write an object, after converting it to a String (if necessary), and after performing any escaping appropriate for
* the markup language being rendered. This method is equivalent to
* {@link #writeText(java.lang.Object,java.lang.String)} but adds a component property to allow custom
* ResponseWriter implementations to associate a component with an arbitrary portion of text.
*
*
*
* The default implementation simply ignores the component argument and calls through to
* {@link #writeText(java.lang.Object,java.lang.String)}
*
*
* @param text Text to be written
* @param component The {@link UIComponent} (if any) to which this element corresponds
* @param property Name of the property or attribute (if any) of the {@link UIComponent} associated with the containing
* element, to which this generated text corresponds
* @throws IOException if an input/output error occurs
* @throws NullPointerException if text is null
* @since 1.2
*/
public void writeText(Object text, UIComponent component, String property) throws IOException {
writeText(text, property);
}
/**
*
* Write text from a character array, after any performing any escaping appropriate for the markup language being
* rendered. If there is an open element that has been created by a call to startElement(), that element
* will be closed first.
*
*
* @param text Text to be written
* @param off Starting offset (zero-relative)
* @param len Number of characters to be written
* @throws IndexOutOfBoundsException if the calculated starting or ending position is outside the bounds of the
* character array
* @throws IOException if an input/output error occurs
* @throws NullPointerException if text is null
*/
public abstract void writeText(char text[], int off, int len) throws IOException;
/**
*
* Create and return a new instance of this {@link ResponseWriter}, using the specified Writer as the
* output destination.
*
*
* @param writer The Writer that is the output destination
*
* @return the new ResponseWriter
*/
public abstract ResponseWriter cloneWithWriter(Writer writer);
}