/* * The Apache Software License, Version 1.1 * * * Copyright (c) 2003 The Apache Software Foundation. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, * if any, must include the following acknowledgment: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowledgment may appear in the software itself, * if and wherever such third-party acknowledgments normally appear. * * 4. The names "Xalan" and "Apache Software Foundation" must * not be used to endorse or promote products derived from this * software without prior written permission. For written * permission, please contact apache@apache.org. * * 5. Products derived from this software may not be called "Apache", * nor may "Apache" appear in their name, without prior written * permission of the Apache Software Foundation. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation and was * originally based on software copyright (c) 2003, International Business * Machines, Inc., http://www.ibm.com. For more information on the Apache * Software Foundation, please see * . */ package org.apache.xml.serializer; /** * This class is a stack frame that consists of * information about the element currently being processed * by a serializer. Consider this example: * 
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* * A stack frame will be pushed for "A" at depth 1, * then another one for "B1" at depth 2. * Then "B1" stackframe is popped. When the stack frame for "B2" is * pushed, this implementation re-uses the old stack fram object used * by "B1" to be efficient at not creating too many of these object. * * This is by no means a public class, and neither are its fields or methods, * they are all helper fields for a serializer. * * The purpose of this class is to be more consistent with pushing information * when a new element is being serialized and more quickly restoring the old * information about the parent element with a simple pop() when the * child element is done. Previously there was some redundant and error-prone * calculations going on to retore information. * */ class ElemContext { // Fields that form the context of the element /** * The nesting depth of the element inside other elements. */ final int m_currentElemDepth; /** HTML field, the element description of the HTML element */ ElemDesc m_elementDesc = null; /** * The local name of the element. */ String m_elementLocalName = null; /** * The fully qualified name of the element (with prefix, if any). */ String m_elementName = null; /** * The URI of the element. */ String m_elementURI = null; /** If the element is in the cdata-section-names list * then the value is true. If it is true the text children of the element * should be output in CDATA section blocks. */ boolean m_isCdataSection; /** True if the current element has output escaping disabled. * This is true for SCRIPT and STYLE elements. */ boolean m_isRaw = false; /** The next element "stack frame". This value will only be * set once as deeper stack frames are not deleted when popped off, * but are rather re-used when a push is required. * * This makes for very fast pushing and popping of stack frames * because very few stack frame objects are ever created, they are * mostly re-used. This re-use saves object creation but it also means * that connections between the frames via m_next and m_prev * never changes either. Just the contents of the frames change * as they are re-used. Only the reference to the current stack frame, which * is held by the serializer is changed via a quick pop() or push(). */ private ElemContext m_next; /** The previous element "stack frame". */ final ElemContext m_prev; /** * Set to true when a start tag is started, or open, but not all the * attributes or namespace information is yet collected. */ boolean m_startTagOpen = false; /** * Constructor to create the root of the element contexts. * */ ElemContext() { // this assignment means can never pop this context off m_prev = this; // depth 0 because it doesn't correspond to any element m_currentElemDepth = 0; } /** * Constructor to create the "stack frame" for a given element depth. * * This implementation will re-use the context at each depth. If * a documents deepest element depth is N then there will be (N+1) * such objects created, no more than that. * * @param previous The "stack frame" corresponding to the new * elements parent element. */ private ElemContext(final ElemContext previous) { m_prev = previous; m_currentElemDepth = previous.m_currentElemDepth + 1; } /** * Pop the current "stack frame". * @return Returns the parent "stack frame" of the one popped. */ final ElemContext pop() { /* a very simple pop. No clean up is done of the deeper * stack frame. All deeper stack frames are still attached * but dormant, just waiting to be re-used. */ return this.m_prev; } /** * This method pushes an element "stack frame" * but with no initialization of values in that frame. * This method is used for optimization purposes, like when pushing * a stack frame for an HTML "IMG" tag which has no children and * the stack frame will almost immediately be popped. */ final ElemContext push() { ElemContext frame = this.m_next; if (frame == null) { /* We have never been at this depth yet, and there is no * stack frame to re-use, so we now make a new one. */ frame = new ElemContext(this); this.m_next = frame; } /* * We shouldn't need to set this true because we should just * be pushing a dummy stack frame that will be instantly popped. * Yet we need to be ready in case this element does have * unexpected children. */ frame.m_startTagOpen = true; return frame; } /** * Push an element context on the stack. This context keeps track of * information gathered about the element. * @param uri The URI for the namespace for the element name, * can be null if it is not yet known. * @param localName The local name of the element (no prefix), * can be null. * @param qName The qualified name (with prefix, if any) * of the element, this parameter is required. */ final ElemContext push( final String uri, final String localName, final String qName) { ElemContext frame = this.m_next; if (frame == null) { /* We have never been at this depth yet, and there is no * stack frame to re-use, so we now make a new one. */ frame = new ElemContext(this); this.m_next = frame; } // Initialize, or reset values in the new or re-used stack frame. frame.m_elementName = qName; frame.m_elementLocalName = localName; frame.m_elementURI = uri; frame.m_isCdataSection = false; frame.m_startTagOpen = true; // is_Raw is already set in the HTML startElement() method // frame.m_isRaw = false; return frame; } }