| /* |
| * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package com.sun.xml.internal.bind.v2.runtime.unmarshaller; |
| |
| import javax.xml.namespace.NamespaceContext; |
| |
| import org.xml.sax.SAXException; |
| |
| /** |
| * Walks the XML document structure. |
| * |
| * Implemented by the unmarshaller and called by the API-specific connectors. |
| * |
| * <h2>Event Call Sequence</h2> |
| * |
| * The {@link XmlVisitor} expects the event callbacks in the following order: |
| * <pre> |
| * CALL SEQUENCE := startDocument ELEMENT endDocument |
| * ELEMENT := startPrefixMapping ELEMENT endPrefixMapping |
| * | startElement BODY endElement |
| * BODY := text? (ELEMENT text?)* |
| * </pre> |
| * Note in particular that text events may not be called in a row; |
| * consecutive characters (even those separated by PIs and comments) |
| * must be reported as one event, unlike SAX. |
| * |
| * <p> |
| * All namespace URIs, local names, and prefixes of element and attribute |
| * names must be interned. qnames need not be interned. |
| * |
| * |
| * <h2>Typed PCDATA</h2> |
| * For efficiency, JAXB RI defines a few {@link CharSequence} implementations |
| * that can be used as a parameter to the {@link #text(CharSequence)} method. |
| * For example, see {@link Base64Data}. |
| * |
| * <h2>Error Handling</h2> |
| * The visitor may throw {@link SAXException} to abort the unmarshalling process |
| * in the middle. |
| * |
| * @author Kohsuke Kawaguchi |
| */ |
| public interface XmlVisitor { |
| /** |
| * Notifies a start of the document. |
| * |
| * @param locator |
| * This live object returns the location information as the parsing progresses. |
| * must not be null. |
| * @param nsContext |
| * Some broken XML APIs can't iterate all the in-scope namespace bindings, |
| * which makes it impossible to emulate {@link #startPrefixMapping(String, String)} correctly |
| * when unmarshalling a subtree. Connectors that use such an API can |
| * pass in additional {@link NamespaceContext} object that knows about the |
| * in-scope namespace bindings. Otherwise (and normally) it is null. |
| * |
| * <p> |
| * Ideally this object should be immutable and only represent the namespace URI bindings |
| * in the context (those done above the element that JAXB started unmarshalling), |
| * but it can also work even if it changes as the parsing progress (to include |
| * namespaces declared on the current element being parsed.) |
| */ |
| void startDocument(LocatorEx locator, NamespaceContext nsContext) throws SAXException; |
| void endDocument() throws SAXException; |
| |
| /** |
| * Notifies a start tag of a new element. |
| * |
| * namespace URIs and local names must be interned. |
| */ |
| void startElement(TagName tagName) throws SAXException; |
| void endElement(TagName tagName) throws SAXException; |
| |
| /** |
| * Called before {@link #startElement} event to notify a new namespace binding. |
| */ |
| void startPrefixMapping( String prefix, String nsUri ) throws SAXException; |
| /** |
| * Called after {@link #endElement} event to notify the end of a binding. |
| */ |
| void endPrefixMapping( String prefix ) throws SAXException; |
| |
| /** |
| * Text events. |
| * |
| * <p> |
| * The caller should consult {@link TextPredictor} to see |
| * if the unmarshaller is expecting any PCDATA. If the above is returning |
| * false, the caller is OK to skip any text in XML. The net effect is |
| * that we can ignore whitespaces quickly. |
| * |
| * @param pcdata |
| * represents character data. This object can be mutable |
| * (such as {@link StringBuilder}); it only needs to be fixed |
| * while this method is executing. |
| */ |
| void text( CharSequence pcdata ) throws SAXException; |
| |
| /** |
| * Returns the {@link UnmarshallingContext} at the end of the chain. |
| * |
| * @return |
| * always return the same object, so caching the result is recommended. |
| */ |
| UnmarshallingContext getContext(); |
| |
| /** |
| * Gets the predictor that can be used for the caller to avoid |
| * calling {@link #text(CharSequence)} unnecessarily. |
| */ |
| TextPredictor getPredictor(); |
| |
| interface TextPredictor { |
| /** |
| * Returns true if the visitor is expecting a text event as the next event. |
| * |
| * <p> |
| * This is primarily intended to be used for optimization to avoid buffering |
| * characters unnecessarily. If this method returns false and the connector |
| * sees whitespace it can safely skip it. |
| * |
| * <p> |
| * If this method returns true, all the whitespaces are considered significant |
| * and thus need to be reported as a {@link XmlVisitor#text} event. Furthermore, |
| * if the element has no children (like {@code <foo/>}), then it has to be reported |
| * an empty {@link XmlVisitor#text} event. |
| */ |
| boolean expectText(); |
| } |
| } |