/*
* 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.
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package javax.servlet.jsp;

import javax.servlet.Servlet;
import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;


The JspFactory is an abstract class that defines a number of factory
methods available to a JSP page at runtime for the purposes of creating
instances of various interfaces and classes used to support the JSP
implementation.

A conformant JSP Engine implementation will, during it's initialization
instantiate an implementation dependent subclass of this class, and make
it globally available for use by JSP implementation classes by registering
the instance created with this class via the
static  setDefaultFactory()  method.

The PageContext and the JspEngineInfo classes are the only
implementation-dependent classes that can be created from the factory.

JspFactory objects should not be used by JSP page authors.
/**
 * <p>
 * The JspFactory is an abstract class that defines a number of factory
 * methods available to a JSP page at runtime for the purposes of creating
 * instances of various interfaces and classes used to support the JSP
 * implementation.
 * <p>
 * A conformant JSP Engine implementation will, during it's initialization
 * instantiate an implementation dependent subclass of this class, and make
 * it globally available for use by JSP implementation classes by registering
 * the instance created with this class via the
 * static <code> setDefaultFactory() </code> method.
 * <p>
 * The PageContext and the JspEngineInfo classes are the only
 * implementation-dependent classes that can be created from the factory.
 * <p>
 * JspFactory objects should not be used by JSP page authors.
 */

public abstract class JspFactory {

    private static volatile JspFactory deflt = null;

    
Sole constructor. (For invocation by subclass constructors,
typically implicit.)
/**
     * Sole constructor. (For invocation by subclass constructors,
     * typically implicit.)
     */
    public JspFactory() {
        // NOOP by default
    }

    

set the default factory for this implementation. It is illegal for
any principal other than the JSP Engine runtime to call this method.

Params:
deflt –        The default factory implementation/**
     * <p>
     * set the default factory for this implementation. It is illegal for
     * any principal other than the JSP Engine runtime to call this method.
     * </p>
     *
     * @param deflt        The default factory implementation
     */

    public static void setDefaultFactory(JspFactory deflt) {
        JspFactory.deflt = deflt;
    }

    
Returns the default factory for this implementation.
Returns:
the default factory for this implementation/**
     * Returns the default factory for this implementation.
     *
     * @return the default factory for this implementation
     */

    public static JspFactory getDefaultFactory() {
        return deflt;
    }

    

obtains an instance of an implementation dependent
javax.servlet.jsp.PageContext abstract class for the calling Servlet
and currently pending request and response.


This method is typically called early in the processing of the
_jspService() method of a JSP implementation class in order to
obtain a PageContext object for the request being processed.


Invoking this method shall result in the PageContext.initialize()
method being invoked. The PageContext returned is properly initialized.


All PageContext objects obtained via this method shall be released
by invoking releasePageContext().

Params:
servlet –      the requesting servlet
request –      the current request pending on the servlet
response –     the current response pending on the servlet
errorPageURL – the URL of the error page for the requesting JSP, or
                        null
needsSession – true if the JSP participates in a session
buffer –  size of buffer in bytes, JspWriter.NO_BUFFER if no buffer, JspWriter.DEFAULT_BUFFER if implementation default.
autoflush –    should the buffer autoflush to the output stream on
                        buffer overflow, or throw an IOException?
See Also:
PageContext
Returns:
the page context/**
     * <p>
     * obtains an instance of an implementation dependent
     * javax.servlet.jsp.PageContext abstract class for the calling Servlet
     * and currently pending request and response.
     * </p>
     *
     * <p>
     * This method is typically called early in the processing of the
     * _jspService() method of a JSP implementation class in order to
     * obtain a PageContext object for the request being processed.
     * </p>
     * <p>
     * Invoking this method shall result in the PageContext.initialize()
     * method being invoked. The PageContext returned is properly initialized.
     * </p>
     * <p>
     * All PageContext objects obtained via this method shall be released
     * by invoking releasePageContext().
     * </p>
     *
     * @param servlet      the requesting servlet
     * @param request      the current request pending on the servlet
     * @param response     the current response pending on the servlet
     * @param errorPageURL the URL of the error page for the requesting JSP, or
     *                         null
     * @param needsSession true if the JSP participates in a session
     * @param buffer       size of buffer in bytes, {@link JspWriter#NO_BUFFER}
     *                         if no buffer, {@link JspWriter#DEFAULT_BUFFER}
     *                         if implementation default.
     * @param autoflush    should the buffer autoflush to the output stream on
     *                         buffer overflow, or throw an IOException?
     *
     * @return the page context
     *
     * @see javax.servlet.jsp.PageContext
     */

    public abstract PageContext getPageContext(Servlet servlet,
            ServletRequest request, ServletResponse response,
            String errorPageURL, boolean needsSession, int buffer,
            boolean autoflush);

    

called to release a previously allocated PageContext object.
Results in PageContext.release() being invoked.
This method should be invoked prior to returning from the _jspService()
method of a JSP implementation class.

Params:
pc – A PageContext previously obtained by getPageContext()/**
     * <p>
     * called to release a previously allocated PageContext object.
     * Results in PageContext.release() being invoked.
     * This method should be invoked prior to returning from the _jspService()
     * method of a JSP implementation class.
     * </p>
     *
     * @param pc A PageContext previously obtained by getPageContext()
     */
    public abstract void releasePageContext(PageContext pc);

    

called to get implementation-specific information on the current JSP
engine.

Returns:
a JspEngineInfo object describing the current JSP engine/**
     * <p>
     * called to get implementation-specific information on the current JSP
     * engine.
     * </p>
     *
     * @return a JspEngineInfo object describing the current JSP engine
     */

    public abstract JspEngineInfo getEngineInfo();

    

Obtain the JspApplicationContext instance that was
associated within the passed ServletContext for this web
application.

Params:
context – the current web application's ServletContext
Returns:
JspApplicationContext instance
Since:
2.1/**
     * <p>
     * Obtain the <code>JspApplicationContext</code> instance that was
     * associated within the passed <code>ServletContext</code> for this web
     * application.
     * </p>
     *
     * @param context the current web application's <code>ServletContext</code>
     * @return <code>JspApplicationContext</code> instance
     * @since 2.1
     */
    public abstract JspApplicationContext getJspApplicationContext(
            ServletContext context);
}