com.amazonservices.mws.client.MwsXmlReader Maven / Gradle / Ivy
/*******************************************************************************
* Copyright 2009-2012 Amazon Services. All Rights Reserved.
* Licensed 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://aws.amazon.com/apache2.0
* This file 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.
*******************************************************************************
* Marketplace Web Service Runtime Client Library
*/
package com.amazonservices.mws.client;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.InputSource;
import javax.xml.datatype.XMLGregorianCalendar;
import javax.xml.parsers.DocumentBuilder;
import java.io.InputStream;
import java.io.StringReader;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;
/**
* A MwsReader that reads XML from a java.io.Reader.
*
* @author mayerj
*/
public class MwsXmlReader implements MwsReader {
/** The input reader under the stream reader. */
private final InputStream is;
/** The parsed document. */
private final Document document;
/**
* The current document element. null if beginObject on missing element.
*/
private Element currentElement;
/**
* The current child of element or null if element has no children. Used for
* round robin searching for elements by name. Most efficient when children
* of element are looked up in order as is the usual case.
*/
private Node currentChild;
/**
* Lookup a child element by tag name.
*
* Will round-robin search using the child field. When returning an element,
* child is set to next element after the found element.
*
* @param name
* The tag name to find.
*
* @return The child element or null.
*/
private Element getChildElement(String name) {
if (currentChild == null) {
// element has no children.
return null;
}
Node start = currentChild;
do {
Node node = currentChild;
currentChild = currentChild.getNextSibling();
if (currentChild == null) {
currentChild = currentElement.getFirstChild();
}
if (node.getNodeType() == Node.ELEMENT_NODE
&& node.getNodeName().equals(name)) {
return (Element) node;
}
} while (currentChild != start);
return null;
}
/**
* Read begin tag, text, end tag.
*
* @param name
*
* @return The trimmed text content or null.
*/
private String getElementText(Element element) {
Node node = element.getFirstChild();
if (node == null || node.getNodeType() != Node.TEXT_NODE) {
return null;
}
return node.getNodeValue().trim();
}
/**
* Read an element into a new instance of a class.
*
* @param element
* The element, if null returns null.
*
* @param cls
* The class to create an instance of.
*
* @return The new instance.
*/
@SuppressWarnings("unchecked")
private T parseElement(Element element, Class cls) {
T value;
if (element == null) {
value = null;
} else if (MwsObject.class.isAssignableFrom(cls)) {
value = MwsUtl.newInstance(cls);
Element holdElement = currentElement;
Node holdChild = currentChild;
setCurrentElement(element);
((MwsObject) value).readFragmentFrom(this);
currentElement = holdElement;
currentChild = holdChild;
} else if (cls == Object.class) {
value = (T)element;
} else {
String v = getElementText(element);
value = parseString(v, cls);
}
return value;
}
/**
* Parse a string to a value of the given class.
*
* @param v
* The string to parse.
* @param cls
* The class to parse it to.
*
* @return The parsed value may be null.
*/
@SuppressWarnings("unchecked")
private T parseString(String v, Class cls) {
Object value;
if (v == null || v.length() == 0) {
value = null;
} else if (cls == String.class) {
value = v;
} else if (cls == Boolean.class || cls == boolean.class) {
if (v.equalsIgnoreCase("true")) {
value = Boolean.TRUE;
} else if (v.equalsIgnoreCase("false")) {
value = Boolean.FALSE;
} else {
throw new IllegalStateException(
"Expected true/false, found text '" + v + "'.");
}
} else if (cls == Integer.class || cls == int.class) {
value = Integer.valueOf(v);
} else if (cls == Long.class || cls == long.class) {
value = Long.valueOf(v);
} else if (cls == Float.class || cls == float.class) {
value = Float.valueOf(v);
} else if (cls == Double.class || cls == double.class) {
value = Double.valueOf(v);
} else if (cls == BigDecimal.class) {
value = new BigDecimal(v);
} else if (XMLGregorianCalendar.class == cls) {
value = MwsUtl.getDTF().newXMLGregorianCalendar(v);
} else if (Enum.class.isAssignableFrom(cls)) {
value = MwsUtl.getEnumValue(cls, v);
} else {
throw new IllegalArgumentException(String.format("Unable to parse String %s to Class %s", v, cls));
}
return (T) value;
}
/**
* Set the current element and positions to its first child.
*
* @param element
*/
private void setCurrentElement(Element element) {
currentElement = element;
currentChild = element.getFirstChild();
}
@Override
public void close() {
MwsUtl.close(is);
}
@Override
public T read(String name, Class cls) {
Element element = getChildElement(name);
T value = parseElement(element, cls);
return value;
}
@Override
public T readAttribute(String name, Class cls) {
return parseString(currentElement.getAttribute(name), cls);
}
@Override
public List readList(String memberName, Class cls) {
List list = new ArrayList();
Node node = currentElement.getFirstChild();
while (node != null) {
if (node.getNodeType() == Node.ELEMENT_NODE
&& node.getNodeName().equals(memberName)) {
// Handle repeating-sibling style lists List readList(String name, String memberName, Class cls) {
List list = new ArrayList();
Node node = currentElement.getFirstChild();
while (node != null && list.isEmpty()) { // Stop if list is non-empty
if (node.getNodeType() == Node.ELEMENT_NODE &&
node.getNodeName().equals(name)) {
// Handle child-member style lists readAny() {
List list = new ArrayList();
Node node = currentElement.getFirstChild();
while (node != null) {
if(node.getNodeType() == Node.ELEMENT_NODE) {
list.add((Element) node);
}
node = node.getNextSibling();
}
return list;
}
@Override
public T readValue(Class cls) {
return parseElement(currentElement, cls);
}
/**
* Create a MwsXmlReader instance around a java.io.InputStream
*
* This constructor wraps the input stream, to close it call the close
* method on the returned instance.
*
* @param is
* The input stream to wrap.
*/
public MwsXmlReader(InputStream is) {
try {
this.is = is;
DocumentBuilder docBuilder = MwsUtl.getDBF().newDocumentBuilder();
document = docBuilder.parse(is);
Element root = document.getDocumentElement();
root.normalize();
setCurrentElement(root);
} catch (Exception e) {
throw MwsUtl.wrap(e);
}
}
/**
* Create a MwsXmlReader instance that reads a string.
*/
public MwsXmlReader(String xml) {
try {
this.is = null;
InputSource src = new InputSource(new StringReader(xml));
DocumentBuilder docBuilder = MwsUtl.getDBF().newDocumentBuilder();
document = docBuilder.parse(src);
Element root = document.getDocumentElement();
root.normalize();
setCurrentElement(root);
} catch (Exception e) {
throw MwsUtl.wrap(e);
}
}
}