| /* |
| * Copyright (c) 1997, 2021 Oracle and/or its affiliates. All rights reserved. |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0, which is available at |
| * http://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| package com.sun.tools.xjc.util; |
| |
| import org.xml.sax.helpers.XMLFilterImpl; |
| import org.xml.sax.helpers.DefaultHandler; |
| import org.xml.sax.XMLFilter; |
| import org.xml.sax.ContentHandler; |
| import org.xml.sax.SAXException; |
| import org.xml.sax.Attributes; |
| |
| /** |
| * {@link XMLFilter} that can cut sub-trees. |
| * |
| * @author Kohsuke Kawaguchi |
| */ |
| public abstract class SubtreeCutter extends XMLFilterImpl { |
| /** |
| * When we are pruning a sub tree, this field holds the depth of |
| * elements that are being cut. Used to resume event forwarding. |
| * |
| * As long as this value is 0, we will pass through data. |
| */ |
| private int cutDepth=0; |
| |
| |
| /** |
| * This object will receive SAX events while a sub tree is being |
| * pruned. |
| */ |
| private static final ContentHandler stub = new DefaultHandler(); |
| |
| /** |
| * This field remembers the user-specified ContentHandler. |
| * So that we can restore it once the sub tree is completely pruned. |
| */ |
| private ContentHandler next; |
| |
| |
| @Override |
| public void startDocument() throws SAXException { |
| cutDepth=0; |
| super.startDocument(); |
| } |
| |
| public boolean isCutting() { |
| return cutDepth>0; |
| } |
| |
| /** |
| * Starts cutting a sub-tree. Should be called from within the |
| * {@link #startElement(String, String, String, Attributes)} implementation |
| * before the execution is passed to {@link SubtreeCutter#startElement(String, String, String, Attributes)} . |
| * The current element will be cut. |
| */ |
| public void startCutting() { |
| super.setContentHandler(stub); |
| cutDepth=1; |
| } |
| |
| @Override |
| public void setContentHandler(ContentHandler handler) { |
| next = handler; |
| // changes take effect immediately unless the sub-tree is being pruned |
| if(getContentHandler()!=stub) |
| super.setContentHandler(handler); |
| } |
| |
| @Override |
| public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException { |
| if(cutDepth>0) |
| cutDepth++; |
| super.startElement(uri, localName, qName, atts); |
| } |
| |
| @Override |
| public void endElement(String namespaceURI, String localName, String qName) throws SAXException { |
| super.endElement(namespaceURI, localName, qName); |
| |
| if( cutDepth!=0 ) { |
| cutDepth--; |
| if( cutDepth == 1 ) { |
| // pruning completed. restore the user handler |
| super.setContentHandler(next); |
| cutDepth=0; |
| } |
| } |
| } |
| } |