109 lines
3.6 KiB
Java
109 lines
3.6 KiB
Java
/*
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* Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package com.sun.tools.internal.xjc.util;
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import org.xml.sax.helpers.XMLFilterImpl;
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import org.xml.sax.helpers.DefaultHandler;
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import org.xml.sax.XMLFilter;
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import org.xml.sax.ContentHandler;
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import org.xml.sax.SAXException;
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import org.xml.sax.Attributes;
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/**
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* {@link XMLFilter} that can cut sub-trees.
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*
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* @author Kohsuke Kawaguchi
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*/
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public abstract class SubtreeCutter extends XMLFilterImpl {
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/**
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* When we are pruning a sub tree, this field holds the depth of
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* elements that are being cut. Used to resume event forwarding.
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*
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* As long as this value is 0, we will pass through data.
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*/
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private int cutDepth=0;
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/**
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* This object will receive SAX events while a sub tree is being
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* pruned.
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*/
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private static final ContentHandler stub = new DefaultHandler();
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/**
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* This field remembers the user-specified ContentHandler.
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* So that we can restore it once the sub tree is completely pruned.
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*/
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private ContentHandler next;
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public void startDocument() throws SAXException {
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cutDepth=0;
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super.startDocument();
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}
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public boolean isCutting() {
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return cutDepth>0;
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}
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/**
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* Starts cutting a sub-tree. Should be called from within the
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* {@link #startElement(String, String, String, Attributes)} implementation
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* before the execution is passed to {@link SubtreeCutter#startElement(String, String, String, Attributes)} .
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* The current element will be cut.
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*/
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public void startCutting() {
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super.setContentHandler(stub);
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cutDepth=1;
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}
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public void setContentHandler(ContentHandler handler) {
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next = handler;
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// changes take effect immediately unless the sub-tree is being pruned
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if(getContentHandler()!=stub)
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super.setContentHandler(handler);
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}
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public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {
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if(cutDepth>0)
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cutDepth++;
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super.startElement(uri, localName, qName, atts);
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}
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public void endElement(String namespaceURI, String localName, String qName) throws SAXException {
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super.endElement(namespaceURI, localName, qName);
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if( cutDepth!=0 ) {
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cutDepth--;
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if( cutDepth == 1 ) {
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// pruning completed. restore the user handler
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super.setContentHandler(next);
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cutDepth=0;
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}
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}
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}
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}
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