org.tinygroup.jspengine.runtime.JspFactoryImpl.java Source code

Introduction

Here is the source code for org.tinygroup.jspengine.runtime.JspFactoryImpl.java

Source

/**
 *  Copyright (c) 1997-2013, www.tinygroup.org (luo_guo@icloud.com).
 *
 *  Licensed under the GPL, Version 3.0 (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.gnu.org/licenses/gpl.html
 *
 *  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.
 */
package org.tinygroup.jspengine.runtime;

import org.tinygroup.jspengine.Constants;
import org.tinygroup.jspengine.org.apache.commons.logging.Log;
import org.tinygroup.jspengine.org.apache.commons.logging.LogFactory;

import javax.servlet.Servlet;
import javax.servlet.ServletContext;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.jsp.JspApplicationContext;
import javax.servlet.jsp.JspEngineInfo;
import javax.servlet.jsp.JspFactory;
import javax.servlet.jsp.PageContext;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.LinkedList;

/**
 * Implementation of JspFactory.
 *
 * @author Anil K. Vijendran
 * @author Kin-man Chung
 */
public class JspFactoryImpl extends JspFactory {

    // Logger
    private static Log log = LogFactory.getLog(JspFactoryImpl.class);

    private static final String SPEC_VERSION = "2.1";
    private static final boolean USE_POOL = true;

    // Per-thread pool of PageContext objects
    private ThreadLocal pool = new ThreadLocal() {
        protected synchronized Object initialValue() {
            return new LinkedList<PageContext>();
        }
    };

    public PageContext getPageContext(Servlet servlet, ServletRequest request, ServletResponse response,
            String errorPageURL, boolean needsSession, int bufferSize, boolean autoflush) {

        if (Constants.IS_SECURITY_ENABLED) {
            PrivilegedGetPageContext dp = new PrivilegedGetPageContext(this, servlet, request, response,
                    errorPageURL, needsSession, bufferSize, autoflush);
            return (PageContext) AccessController.doPrivileged(dp);
        } else {
            return internalGetPageContext(servlet, request, response, errorPageURL, needsSession, bufferSize,
                    autoflush);
        }
    }

    public void releasePageContext(PageContext pc) {
        if (pc == null)
            return;
        if (Constants.IS_SECURITY_ENABLED) {
            PrivilegedReleasePageContext dp = new PrivilegedReleasePageContext(this, pc);
            AccessController.doPrivileged(dp);
        } else {
            internalReleasePageContext(pc);
        }
    }

    public JspEngineInfo getEngineInfo() {
        return new JspEngineInfo() {
            public String getSpecificationVersion() {
                return SPEC_VERSION;
            }
        };
    }

    public JspApplicationContext getJspApplicationContext(ServletContext context) {
        return JspApplicationContextImpl.findJspApplicationContext(context);
    }

    private PageContext internalGetPageContext(Servlet servlet, ServletRequest request, ServletResponse response,
            String errorPageURL, boolean needsSession, int bufferSize, boolean autoflush) {
        try {
            PageContext pc = null;
            if (USE_POOL) {
                LinkedList<PageContext> pcPool = (LinkedList<PageContext>) pool.get();
                if (!pcPool.isEmpty()) {
                    pc = pcPool.removeFirst();
                }
                if (pc == null) {
                    pc = new PageContextImpl(this);
                }
            } else {
                pc = new PageContextImpl(this);
            }
            pc.initialize(servlet, request, response, errorPageURL, needsSession, bufferSize, autoflush);
            return pc;
        } catch (Throwable ex) {
            /* FIXME: need to do something reasonable here!! */
            log.fatal("Exception initializing page context", ex);
            return null;
        }
    }

    private void internalReleasePageContext(PageContext pc) {
        pc.release();
        if (USE_POOL && (pc instanceof PageContextImpl)) {
            LinkedList<PageContext> pcPool = (LinkedList<PageContext>) pool.get();
            pcPool.addFirst(pc);
        }
    }

    private class PrivilegedGetPageContext implements PrivilegedAction {

        private JspFactoryImpl factory;
        private Servlet servlet;
        private ServletRequest request;
        private ServletResponse response;
        private String errorPageURL;
        private boolean needsSession;
        private int bufferSize;
        private boolean autoflush;

        PrivilegedGetPageContext(JspFactoryImpl factory, Servlet servlet, ServletRequest request,
                ServletResponse response, String errorPageURL, boolean needsSession, int bufferSize,
                boolean autoflush) {
            this.factory = factory;
            this.servlet = servlet;
            this.request = request;
            this.response = response;
            this.errorPageURL = errorPageURL;
            this.needsSession = needsSession;
            this.bufferSize = bufferSize;
            this.autoflush = autoflush;
        }

        public Object run() {
            return factory.internalGetPageContext(servlet, request, response, errorPageURL, needsSession,
                    bufferSize, autoflush);
        }
    }

    private class PrivilegedReleasePageContext implements PrivilegedAction {

        private JspFactoryImpl factory;
        private PageContext pageContext;

        PrivilegedReleasePageContext(JspFactoryImpl factory, PageContext pageContext) {
            this.factory = factory;
            this.pageContext = pageContext;
        }

        public Object run() {
            factory.internalReleasePageContext(pageContext);
            return null;
        }
    }
}