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Axis2 Data Binding module
/*
* 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.axis2.databinding.utils;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
/**
* A state machine to read elements with simple content. Returns the text of the element and the
* stream reader will be one event beyond the end element at return
*/
public class SimpleElementReaderStateMachine implements States, Constants {
private QName elementNameToTest = null;
private int currentState = INIT_STATE;
private boolean nillable = false;
private String text = "";
private String errorMessage = "";
private boolean elementSkipped = false;
public boolean isElementSkipped() {
return elementSkipped;
}
/**
*
*/
public String getText() {
return text;
}
/** sets the nillable flag */
public void setNillable() {
nillable = true;
}
/**
* the Qname of the element to be tested
*
* @param elementNameToTest
*/
public void setElementNameToTest(QName elementNameToTest) {
this.elementNameToTest = elementNameToTest;
}
/**
* Resets the state machine. Once the reset is called the state machine is good enough for a
* fresh run
*/
public void reset() {
elementNameToTest = null;
currentState = INIT_STATE;
nillable = false;
text = "";
errorMessage = "";
}
/**
* public read method - reads a given reader to extract the text value
*
* @param reader
*/
public void read(XMLStreamReader reader) throws XMLStreamException {
do {
updateState(reader);
//test for the nillable attribute
if (currentState == START_ELEMENT_FOUND_STATE &&
nillable) {
if (TRUE.equals(reader.getAttributeValue(XSI_NAMESPACE, NIL))) {
text = null;
//force the state to be null found
currentState = NULLED_STATE;
}
}
if (currentState == TEXT_FOUND_STATE) {
//read the text value and store it
text = reader.getText();
}
if (currentState != FINISHED_STATE
&& currentState != ILLEGAL_STATE) {
reader.next();
}
} while (currentState != FINISHED_STATE
&& currentState != ILLEGAL_STATE);
if (currentState == ILLEGAL_STATE) {
throw new RuntimeException("Illegal state!" + errorMessage);
}
}
/**
* Updates the state depending on the parser
*
* @param reader
*/
private void updateState(XMLStreamReader reader) throws XMLStreamException {
int event = reader.getEventType();
switch (currentState) {
case INIT_STATE:
if (event == XMLStreamConstants.START_DOCUMENT) {
currentState = STARTED_STATE;
//start element found at init
} else if (event == XMLStreamConstants.START_ELEMENT) {
if (elementNameToTest.equals(reader.getName())) {
currentState = START_ELEMENT_FOUND_STATE;
} else {
currentState = STARTED_STATE;
}
} else if (event == XMLStreamConstants.END_ELEMENT) {
// an end element is found at the init state
// we should break the process here ?
currentState = FINISHED_STATE;
elementSkipped = true;
}
break;
case STARTED_STATE:
if (event == XMLStreamConstants.START_ELEMENT) {
if (elementNameToTest.equals(reader.getName())) {
currentState = START_ELEMENT_FOUND_STATE;
}
}
break;
case START_ELEMENT_FOUND_STATE:
if (event == XMLStreamConstants.CHARACTERS) {
currentState = TEXT_FOUND_STATE;
} else if (event == XMLStreamConstants.END_ELEMENT) {
//force the text to be empty!
text = "";
if (elementNameToTest.equals(reader.getName())) {
currentState = END_ELEMENT_FOUND_STATE;
} else {
currentState = ILLEGAL_STATE;
errorMessage = "Wrong element name " + reader.getName(); //todo I18n this
}
}
break;
case TEXT_FOUND_STATE:
if (event == XMLStreamConstants.END_ELEMENT) {
if (elementNameToTest.equals(reader.getName())) {
currentState = END_ELEMENT_FOUND_STATE;
} else {
currentState = ILLEGAL_STATE;
//set the error message
errorMessage = "Wrong element name " + reader.getName(); //todo I18n this
}
} else if (event == XMLStreamConstants.CHARACTERS) {
text = text + reader.getText(); //append the text
//do not change the state
}
break;
case END_ELEMENT_FOUND_STATE:
currentState = FINISHED_STATE;
break;
//the element was found to be null and this state was forced.
//we are sure here that the parser was at the
//START_ELEMENT_FOUND_STATE before
//being forced. Hence we need to advance the parser upto the
// end element and set the state to be end element found
case NULLED_STATE:
while (event != XMLStreamConstants.END_ELEMENT) {
event = reader.next();
}
currentState = END_ELEMENT_FOUND_STATE;
break;
default:
if (event == XMLStreamConstants.CHARACTERS) {
if (reader.getText().trim().length() == 0) {
//the text is empty - don't change the state
} else {
//we do NOT handle mixed content
currentState = ILLEGAL_STATE;
errorMessage = "Mixed Content " + reader.getText();
}
} else {
currentState = ILLEGAL_STATE;
errorMessage = "Current state is " + currentState;
}
break;
}
}
}