Java tutorial
/* * Copyright 2001-2002,2004 The Apache Software Foundation. * * 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://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.axis.encoding.ser; import java.io.CharArrayWriter; import java.io.Serializable; import java.lang.reflect.Constructor; import java.util.Map; import javax.xml.namespace.QName; import org.apache.axis.Constants; import org.apache.axis.components.logger.LogFactory; import org.apache.axis.description.ElementDesc; import org.apache.axis.description.FieldDesc; import org.apache.axis.description.TypeDesc; import org.apache.axis.encoding.ConstructorTarget; import org.apache.axis.encoding.DeserializationContext; import org.apache.axis.encoding.Deserializer; import org.apache.axis.encoding.DeserializerImpl; import org.apache.axis.encoding.Target; import org.apache.axis.encoding.TypeMapping; import org.apache.axis.message.MessageElement; import org.apache.axis.message.SOAPHandler; import org.apache.axis.soap.SOAPConstants; import org.apache.axis.utils.BeanPropertyDescriptor; import org.apache.axis.utils.Messages; import org.apache.commons.logging.Log; import org.xml.sax.Attributes; import org.xml.sax.SAXException; /** * General purpose deserializer for an arbitrary java bean. * * @author Sam Ruby <rubys@us.ibm.com> * @author Rich Scheuerle <scheu@us.ibm.com> * @author Tom Jordahl <tomj@macromedia.com> */ public class BeanDeserializer extends DeserializerImpl implements Serializable { protected static Log log = LogFactory.getLog(BeanDeserializer.class.getName()); private final CharArrayWriter val = new CharArrayWriter(); QName xmlType; Class javaType; protected Map propertyMap = null; protected QName prevQName; /** * Constructor if no default constructor */ protected Constructor constructorToUse = null; /** * Constructor Target object to use (if constructorToUse != null) */ protected Target constructorTarget = null; /** Type metadata about this class for XML deserialization */ protected TypeDesc typeDesc = null; // This counter is updated to deal with deserialize collection properties protected int collectionIndex = -1; protected SimpleDeserializer cacheStringDSer = null; protected QName cacheXMLType = null; // Construct BeanSerializer for the indicated class/qname public BeanDeserializer(Class javaType, QName xmlType) { this(javaType, xmlType, TypeDesc.getTypeDescForClass(javaType)); } // Construct BeanDeserializer for the indicated class/qname and meta Data public BeanDeserializer(Class javaType, QName xmlType, TypeDesc typeDesc) { this(javaType, xmlType, typeDesc, BeanDeserializerFactory.getProperties(javaType, typeDesc)); } // Construct BeanDeserializer for the indicated class/qname and meta Data public BeanDeserializer(Class javaType, QName xmlType, TypeDesc typeDesc, Map propertyMap) { this.xmlType = xmlType; this.javaType = javaType; this.typeDesc = typeDesc; this.propertyMap = propertyMap; // create a value try { value = javaType.newInstance(); } catch (Exception e) { // Don't process the exception at this point. // This is defered until the call to startElement // which will throw the exception. } } /** * startElement * * The ONLY reason that this method is overridden is so that * the object value can be set or a reasonable exception is thrown * indicating that the object cannot be created. This is done * at this point so that it occurs BEFORE href/id processing. * @param namespace is the namespace of the element * @param localName is the name of the element * @param prefix is the prefix of the element * @param attributes are the attributes on the element...used to get the * type * @param context is the DeserializationContext */ public void startElement(String namespace, String localName, String prefix, Attributes attributes, DeserializationContext context) throws SAXException { // Create the bean object if it was not already // created in the constructor. if (value == null) { try { value = javaType.newInstance(); } catch (Exception e) { // Use first found constructor. // Note : the right way is to use XML mapping information // for example JSR 109's constructor-parameter-order Constructor[] constructors = javaType.getConstructors(); if (constructors.length > 0) { constructorToUse = constructors[0]; } // Failed to create an object if no constructor if (constructorToUse == null) { throw new SAXException( Messages.getMessage("cantCreateBean00", javaType.getName(), e.toString())); } } } // Invoke super.startElement to do the href/id processing. super.startElement(namespace, localName, prefix, attributes, context); } /** * Deserializer interface called on each child element encountered in * the XML stream. * @param namespace is the namespace of the child element * @param localName is the local name of the child element * @param prefix is the prefix used on the name of the child element * @param attributes are the attributes of the child element * @param context is the deserialization context. * @return is a Deserializer to use to deserialize a child (must be * a derived class of SOAPHandler) or null if no deserialization should * be performed. */ public SOAPHandler onStartChild(String namespace, String localName, String prefix, Attributes attributes, DeserializationContext context) throws SAXException { handleMixedContent(); BeanPropertyDescriptor propDesc = null; FieldDesc fieldDesc = null; SOAPConstants soapConstants = context.getSOAPConstants(); String encodingStyle = context.getEncodingStyle(); boolean isEncoded = Constants.isSOAP_ENC(encodingStyle); QName elemQName = new QName(namespace, localName); // The collectionIndex needs to be reset for Beans with multiple arrays if ((prevQName == null) || (!prevQName.equals(elemQName))) { collectionIndex = -1; } boolean isArray = false; QName itemQName = null; if (typeDesc != null) { // Lookup the name appropriately (assuming an unqualified // name for SOAP encoding, using the namespace otherwise) String fieldName = typeDesc.getFieldNameForElement(elemQName, isEncoded); propDesc = (BeanPropertyDescriptor) propertyMap.get(fieldName); fieldDesc = typeDesc.getFieldByName(fieldName); if (fieldDesc != null) { ElementDesc element = (ElementDesc) fieldDesc; isArray = element.isMaxOccursUnbounded(); itemQName = element.getItemQName(); } } if (propDesc == null) { // look for a field by this name. propDesc = (BeanPropertyDescriptor) propertyMap.get(localName); } // Workaround if (propDesc == null) { StringBuffer sb = new StringBuffer(); sb.append(Character.toLowerCase(localName.charAt(0))); if (localName.length() > 1) sb.append(localName.substring(1)); // look for a field by this name. propDesc = (BeanPropertyDescriptor) propertyMap.get(sb.toString()); } // try and see if this is an xsd:any namespace="##any" element before // reporting a problem if (propDesc == null || (((prevQName != null) && prevQName.equals(elemQName) && !(propDesc.isIndexed() || isArray) && getAnyPropertyDesc() != null))) { // try to put unknown elements into a SOAPElement property, if // appropriate prevQName = elemQName; propDesc = getAnyPropertyDesc(); if (propDesc != null) { try { MessageElement[] curElements = (MessageElement[]) propDesc.get(value); int length = 0; if (curElements != null) { length = curElements.length; } MessageElement[] newElements = new MessageElement[length + 1]; if (curElements != null) { System.arraycopy(curElements, 0, newElements, 0, length); } MessageElement thisEl = context.getCurElement(); newElements[length] = thisEl; propDesc.set(value, newElements); // if this is the first pass through the MessageContexts // make sure that the correct any element is set, // that is the child of the current MessageElement, however // on the first pass this child has not been set yet, so // defer it to the child SOAPHandler if (!localName.equals(thisEl.getName())) { return new SOAPHandler(newElements, length); } return new SOAPHandler(); } catch (Exception e) { throw new SAXException(e); } } } if (propDesc == null) { // No such field throw new SAXException(Messages.getMessage("badElem00", javaType.getName(), localName)); } prevQName = elemQName; // Get the child's xsi:type if available QName childXMLType = context.getTypeFromAttributes(namespace, localName, attributes); String href = attributes.getValue(soapConstants.getAttrHref()); Class fieldType = propDesc.getType(); // If no xsi:type or href, check the meta-data for the field if (childXMLType == null && fieldDesc != null && href == null) { childXMLType = fieldDesc.getXmlType(); if (itemQName != null) { // This is actually a wrapped literal array and should be // deserialized with the ArrayDeserializer childXMLType = Constants.SOAP_ARRAY; fieldType = propDesc.getActualType(); } else { childXMLType = fieldDesc.getXmlType(); } } // Get Deserializer for child, default to using DeserializerImpl Deserializer dSer = getDeserializer(childXMLType, fieldType, href, context); // It is an error if the dSer is not found - the only case where we // wouldn't have a deserializer at this point is when we're trying // to deserialize something we have no clue about (no good xsi:type, // no good metadata). if (dSer == null) { dSer = context.getDeserializerForClass(propDesc.getType()); } // Fastpath nil checks... if (context.isNil(attributes)) { if ((propDesc.isIndexed() || isArray)) { if (!((dSer != null) && (dSer instanceof ArrayDeserializer))) { collectionIndex++; dSer.registerValueTarget(new BeanPropertyTarget(value, propDesc, collectionIndex)); addChildDeserializer(dSer); return (SOAPHandler) dSer; } } return null; } if (dSer == null) { throw new SAXException(Messages.getMessage("noDeser00", childXMLType.toString())); } if (constructorToUse != null) { if (constructorTarget == null) { constructorTarget = new ConstructorTarget(constructorToUse, this); } dSer.registerValueTarget(constructorTarget); } else if (propDesc.isWriteable()) { // If this is an indexed property, and the deserializer we found // was NOT the ArrayDeserializer, this is a non-SOAP array: // <bean> // <field>value1</field> // <field>value2</field> // ... // In this case, we want to use the collectionIndex and make sure // the deserialized value for the child element goes into the // right place in the collection. // Register value target if ((itemQName != null || propDesc.isIndexed() || isArray) && !(dSer instanceof ArrayDeserializer)) { collectionIndex++; dSer.registerValueTarget(new BeanPropertyTarget(value, propDesc, collectionIndex)); } else { // If we're here, the element maps to a single field value, // whether that be a "basic" type or an array, so use the // normal (non-indexed) BeanPropertyTarget form. collectionIndex = -1; dSer.registerValueTarget(new BeanPropertyTarget(value, propDesc)); } } // Let the framework know that we need this deserializer to complete // for the bean to complete. addChildDeserializer(dSer); return (SOAPHandler) dSer; } /** * Get a BeanPropertyDescriptor which indicates where we should * put extensibility elements (i.e. XML which falls under the * auspices of an <xsd:any> declaration in the schema) * * @return an appropriate BeanPropertyDescriptor, or null */ public BeanPropertyDescriptor getAnyPropertyDesc() { if (typeDesc == null) return null; return typeDesc.getAnyDesc(); } /** * Set the bean properties that correspond to element attributes. * * This method is invoked after startElement when the element requires * deserialization (i.e. the element is not an href and the value is not * nil.) * @param namespace is the namespace of the element * @param localName is the name of the element * @param prefix is the prefix of the element * @param attributes are the attributes on the element...used to get the * type * @param context is the DeserializationContext */ public void onStartElement(String namespace, String localName, String prefix, Attributes attributes, DeserializationContext context) throws SAXException { // The value should have been created or assigned already. // This code may no longer be needed. if (value == null && constructorToUse == null) { // create a value try { value = javaType.newInstance(); } catch (Exception e) { throw new SAXException(Messages.getMessage("cantCreateBean00", javaType.getName(), e.toString())); } } // If no type description meta data, there are no attributes, // so we are done. if (typeDesc == null) return; // loop through the attributes and set bean properties that // correspond to attributes for (int i = 0; i < attributes.getLength(); i++) { QName attrQName = new QName(attributes.getURI(i), attributes.getLocalName(i)); String fieldName = typeDesc.getFieldNameForAttribute(attrQName); if (fieldName == null) continue; FieldDesc fieldDesc = typeDesc.getFieldByName(fieldName); // look for the attribute property BeanPropertyDescriptor bpd = (BeanPropertyDescriptor) propertyMap.get(fieldName); if (bpd != null) { if (constructorToUse == null) { // check only if default constructor if (!bpd.isWriteable() || bpd.isIndexed()) continue; } // Get the Deserializer for the attribute Deserializer dSer = getDeserializer(fieldDesc.getXmlType(), bpd.getType(), null, context); if (dSer == null) { dSer = context.getDeserializerForClass(bpd.getType()); // The java type is an array, but the context didn't // know that we are an attribute. Better stick with // simple types.. if (dSer instanceof ArrayDeserializer) { SimpleListDeserializerFactory factory = new SimpleListDeserializerFactory(bpd.getType(), fieldDesc.getXmlType()); dSer = (Deserializer) factory.getDeserializerAs(dSer.getMechanismType()); } } if (dSer == null) throw new SAXException(Messages.getMessage("unregistered00", bpd.getType().toString())); if (!(dSer instanceof SimpleDeserializer)) throw new SAXException( Messages.getMessage("AttrNotSimpleType00", bpd.getName(), bpd.getType().toString())); // Success! Create an object from the string and set // it in the bean try { dSer.onStartElement(namespace, localName, prefix, attributes, context); Object val = ((SimpleDeserializer) dSer).makeValue(attributes.getValue(i)); if (constructorToUse == null) { bpd.set(value, val); } else { // add value for our constructor if (constructorTarget == null) { constructorTarget = new ConstructorTarget(constructorToUse, this); } constructorTarget.set(val); } } catch (Exception e) { throw new SAXException(e); } } // if } // attribute loop } /** * Get the Deserializer for the attribute or child element. * @param xmlType QName of the attribute/child element or null if not known. * @param javaType Class of the corresponding property * @param href String is the value of the href attribute, which is used * to determine whether the child element is complete or an * href to another element. * @param context DeserializationContext * @return Deserializer or null if not found. */ protected Deserializer getDeserializer(QName xmlType, Class javaType, String href, DeserializationContext context) { if (javaType.isArray()) { context.setDestinationClass(javaType); } // See if we have a cached deserializer if (cacheStringDSer != null) { if (String.class.equals(javaType) && href == null && (cacheXMLType == null && xmlType == null || cacheXMLType != null && cacheXMLType.equals(xmlType))) { cacheStringDSer.reset(); return cacheStringDSer; } } Deserializer dSer = null; if (xmlType != null && href == null) { // Use the xmlType to get the deserializer. dSer = context.getDeserializerForType(xmlType); } else { // If the xmlType is not set, get a default xmlType TypeMapping tm = context.getTypeMapping(); QName defaultXMLType = tm.getTypeQName(javaType); // If there is not href, then get the deserializer // using the javaType and default XMLType, // If there is an href, the create the generic // DeserializerImpl and set its default type (the // default type is used if the href'd element does // not have an xsi:type. if (href == null) { dSer = context.getDeserializer(javaType, defaultXMLType); } else { dSer = new DeserializerImpl(); context.setDestinationClass(javaType); dSer.setDefaultType(defaultXMLType); } } if (javaType.equals(String.class) && dSer instanceof SimpleDeserializer) { cacheStringDSer = (SimpleDeserializer) dSer; cacheXMLType = xmlType; } return dSer; } public void characters(char[] chars, int start, int end) throws SAXException { val.write(chars, start, end); } public void onEndElement(String namespace, String localName, DeserializationContext context) throws SAXException { handleMixedContent(); } protected void handleMixedContent() throws SAXException { BeanPropertyDescriptor propDesc = getAnyPropertyDesc(); if (propDesc == null || val.size() == 0) { return; } String textValue = val.toString().trim(); val.reset(); if (textValue.length() == 0) { return; } try { MessageElement[] curElements = (MessageElement[]) propDesc.get(value); int length = 0; if (curElements != null) { length = curElements.length; } MessageElement[] newElements = new MessageElement[length + 1]; if (curElements != null) { System.arraycopy(curElements, 0, newElements, 0, length); } MessageElement thisEl = new MessageElement(new org.apache.axis.message.Text(textValue)); newElements[length] = thisEl; propDesc.set(value, newElements); } catch (Exception e) { throw new SAXException(e); } } }