| /* |
| * 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. |
| */ |
| |
| package org.apache.jasper.runtime; |
| |
| import javax.servlet.ServletConfig; |
| import javax.servlet.jsp.JspException; |
| import javax.servlet.jsp.tagext.Tag; |
| |
| import org.apache.jasper.Constants; |
| import org.apache.juli.logging.Log; |
| import org.apache.juli.logging.LogFactory; |
| import org.apache.tomcat.InstanceManager; |
| |
| /** |
| * Pool of tag handlers that can be reused. |
| * |
| * @author Jan Luehe |
| */ |
| public class TagHandlerPool { |
| |
| private Tag[] handlers; |
| |
| public static final String OPTION_TAGPOOL="tagpoolClassName"; |
| public static final String OPTION_MAXSIZE="tagpoolMaxSize"; |
| |
| private final Log log = LogFactory.getLog(TagHandlerPool.class); |
| |
| // index of next available tag handler |
| private int current; |
| protected InstanceManager instanceManager = null; |
| |
| public static TagHandlerPool getTagHandlerPool( ServletConfig config) { |
| TagHandlerPool result=null; |
| |
| String tpClassName=getOption( config, OPTION_TAGPOOL, null); |
| if( tpClassName != null ) { |
| try { |
| Class<?> c=Class.forName( tpClassName ); |
| result=(TagHandlerPool)c.newInstance(); |
| } catch (Exception e) { |
| e.printStackTrace(); |
| result=null; |
| } |
| } |
| if( result==null ) result=new TagHandlerPool(); |
| result.init(config); |
| |
| return result; |
| } |
| |
| protected void init( ServletConfig config ) { |
| int maxSize=-1; |
| String maxSizeS=getOption(config, OPTION_MAXSIZE, null); |
| if( maxSizeS != null ) { |
| try { |
| maxSize=Integer.parseInt(maxSizeS); |
| } catch( Exception ex) { |
| maxSize=-1; |
| } |
| } |
| if( maxSize <0 ) { |
| maxSize=Constants.MAX_POOL_SIZE; |
| } |
| this.handlers = new Tag[maxSize]; |
| this.current = -1; |
| instanceManager = InstanceManagerFactory.getInstanceManager(config); |
| } |
| |
| /** |
| * Constructs a tag handler pool with the default capacity. |
| */ |
| public TagHandlerPool() { |
| // Nothing - jasper generated servlets call the other constructor, |
| // this should be used in future + init . |
| } |
| |
| /** |
| * Gets the next available tag handler from this tag handler pool, |
| * instantiating one if this tag handler pool is empty. |
| * |
| * @param handlerClass Tag handler class |
| * |
| * @return Reused or newly instantiated tag handler |
| * |
| * @throws JspException if a tag handler cannot be instantiated |
| */ |
| public Tag get(Class<? extends Tag> handlerClass) throws JspException { |
| Tag handler; |
| synchronized( this ) { |
| if (current >= 0) { |
| handler = handlers[current--]; |
| return handler; |
| } |
| } |
| |
| // Out of sync block - there is no need for other threads to |
| // wait for us to construct a tag for this thread. |
| try { |
| if (Constants.USE_INSTANCE_MANAGER_FOR_TAGS) { |
| return (Tag) instanceManager.newInstance(handlerClass.getName(), handlerClass.getClassLoader()); |
| } else { |
| Tag instance = handlerClass.newInstance(); |
| instanceManager.newInstance(instance); |
| return instance; |
| } |
| } catch (Exception e) { |
| throw new JspException(e.getMessage(), e); |
| } |
| } |
| |
| /** |
| * Adds the given tag handler to this tag handler pool, unless this tag |
| * handler pool has already reached its capacity, in which case the tag |
| * handler's release() method is called. |
| * |
| * @param handler Tag handler to add to this tag handler pool |
| */ |
| public void reuse(Tag handler) { |
| synchronized( this ) { |
| if (current < (handlers.length - 1)) { |
| handlers[++current] = handler; |
| return; |
| } |
| } |
| // There is no need for other threads to wait for us to release |
| handler.release(); |
| try { |
| instanceManager.destroyInstance(handler); |
| } catch (Exception e) { |
| log.warn("Error processing preDestroy on tag instance of " |
| + handler.getClass().getName(), e); |
| } |
| } |
| |
| /** |
| * Calls the release() method of all available tag handlers in this tag |
| * handler pool. |
| */ |
| public synchronized void release() { |
| for (int i = current; i >= 0; i--) { |
| handlers[i].release(); |
| try { |
| instanceManager.destroyInstance(handlers[i]); |
| } catch (Exception e) { |
| log.warn("Error processing preDestroy on tag instance of " |
| + handlers[i].getClass().getName(), e); |
| } |
| } |
| } |
| |
| protected static String getOption( ServletConfig config, String name, String defaultV) { |
| if( config == null ) return defaultV; |
| |
| String value=config.getInitParameter(name); |
| if( value != null ) return value; |
| if( config.getServletContext() ==null ) |
| return defaultV; |
| value=config.getServletContext().getInitParameter(name); |
| if( value!=null ) return value; |
| return defaultV; |
| } |
| |
| } |
| |