com.tangosol.run.xml.CollectionAdapter Maven / Gradle / Ivy
/*
* Copyright (c) 2000, 2020, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
package com.tangosol.run.xml;
import com.tangosol.util.ClassHelper;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
/**
* A CollectionAdapter supports properties whose types implement the
* java.util.Collection interface.
*
* <property>
* <name>People</name>
* <xml-name>people</xml-name> <!-- defaults to <name> -->
* <type>java.util.Collection</type> <!-- defaults via reflection -->
* <class>java.util.LinkedList</class> <!-- defaults to <type> -->
* <empty-is-null>true</empty-is-null> <!-- defaults to false -->
* <element>
* <xml-name>person</xml-name> <!-- optional, nests the elements -->
* <type>com...PersonBean</type> <!-- required -->
* <adapter>...</adapter> <!-- optional -->
* <...> <!-- for the type-specific adapter -->
* </element>
* </property>
*
*
* Example of collection nested within collection tags:
*
* <doc>
* <people>
* <person>
* <...>
* </person>
* <person>
* <...>
* </person>
* ...
* </people>
* </doc>
*
*
* @version 1.00 2001.03.18
* @author cp
*/
public class CollectionAdapter
extends IterableAdapter
{
// ----- constructors ---------------------------------------------------
/**
* Construct a CollectionAdapter.
*
* @param infoBean BeanInfo for a bean containing this property
* @param clzType the type of the property
* @param sName the property name
* @param sXml the XML tag name
* @param xml additional XML information
*/
public CollectionAdapter(XmlBean.BeanInfo infoBean, Class clzType, String sName, String sXml, XmlElement xml)
{
super(infoBean, clzType, sName, sXml, xml);
azzert(Collection.class.isAssignableFrom(clzType));
// determine the collection class used
Class clzCollection = getType();
XmlValue xmlClz = xml.getElement("class");
if (xmlClz != null)
{
clzCollection = infoBean.resolveClass(xmlClz.getString());
}
m_clzCollection = clzCollection;
XmlElement xmlElement = xml.getElement("element");
if (xmlElement == null)
{
throw new IllegalStateException(
"Missing the \"\" information for the \"" +
sName + "\" property of the \"" +
ClassHelper.getSimpleName(infoBean.getType()) +
"\" XmlBean.");
}
m_adapterElement = findAdapter(infoBean, xmlElement);
}
// ----- Object method helpers ------------------------------------------
/**
* Make a clone of the passed object.
*
* @param o the object to clone
*
* @return a clone of the passed object
*/
public Object clone(Object o)
{
if (o == null)
{
return null;
}
PropertyAdapter adapterElement = m_adapterElement;
Collection colOld = (Collection) o;
Collection colNew = instantiateCollection();
for (Iterator iter = colOld.iterator(); iter.hasNext(); )
{
Object oElement = iter.next();
if (oElement != null)
{
oElement = adapterElement.clone(oElement);
}
colNew.add(oElement);
}
return colNew;
}
// ----- XmlSerializable helpers ----------------------------------------
/**
* @param xml the XML element containing the XML elements to deserialize
* from
*
* @return the object deserialized from the XML (not null)
*/
protected Object readElements(XmlElement xml)
{
Collection collection = instantiateCollection();
PropertyAdapter adapterElement = m_adapterElement;
boolean fAnonymous = adapterElement.isAnonymous();
Iterator iter = fAnonymous ?
xml.getElementList().iterator() :
XmlHelper.getElements(
xml, getElementName(), adapterElement.getNamespaceUri());
while (iter.hasNext())
{
XmlElement xmlElement = (XmlElement) iter.next();
Object oElement = adapterElement.fromXml(xmlElement);
// anonymous collections do not allow null elements
if (!fAnonymous || oElement != null)
{
collection.add(oElement);
}
}
return collection;
}
/**
* @param xml the XML element to which the iterable elements are written
* @param o the object to serialize (not null)
*/
protected void writeElements(XmlElement xml, Object o)
{
Collection collection = (Collection) o;
if (collection.isEmpty())
{
return;
}
PropertyAdapter adapterElement = m_adapterElement;
boolean fAnonymous = adapterElement.isAnonymous();
String sNmsPrefix = null;
String sElement = null;
if (!fAnonymous)
{
sNmsPrefix = adapterElement.getNamespacePrefix();
sElement = XmlHelper.getUniversalName(getElementName(), sNmsPrefix);
}
List list = xml.getElementList();
for (Iterator iter = ((Collection) o).iterator(); iter.hasNext();)
{
Object oElement = iter.next();
// the following is almost identical to a call
// adapterElement.writeXml(xml, oElement);
// except that the element name could be different
XmlElement xmlElement = adapterElement.toXml(oElement);
if (xmlElement != null)
{
if (fAnonymous)
{
List listElement = xmlElement.getElementList();
int cElements = listElement.size();
if (cElements == 1)
{
list.add(listElement.get(0));
}
else if (cElements > 1)
{
throw new IllegalStateException("Too many elements: " + xmlElement +
"\nadapter=" + adapterElement);
}
}
else
{
xmlElement.setName(sElement);
list.add(xmlElement);
}
}
}
/*
if (sNmsPrefix != null)
{
XmlHelper.ensureNamespace(xml, sNmsPrefix, adapterElement.getNamespaceUri());
XmlHelper.purgeChildrenNamespace(xml);
}
*/
}
// ----- ExternalizableLite helpers -------------------------------------
/**
* Read a value from the passed DataInput object.
*
* @param in the DataInput stream to read property data from
*
* @return the data read from the DataInput; never null
*
* @exception IOException if an I/O exception occurs
*/
public Object readExternal(DataInput in)
throws IOException
{
Collection collection = instantiateCollection();
PropertyAdapter adapter = getElementAdapter();
// "in" contains a collection size and, for each element, a non-null
// indicator and (if non-null) the object
for (int i = 0, c = readInt(in); i < c; ++i)
{
collection.add(in.readBoolean() ? adapter.readExternal(in) : null);
}
return collection;
}
/**
* Write the specified data to the passed DataOutput object.
*
* @param out the DataOutput stream to write to
* @param o the data to write to the DataOutput; never null
*
* @exception IOException if an I/O exception occurs
*/
public void writeExternal(DataOutput out, Object o)
throws IOException
{
Collection collection = (Collection) o;
PropertyAdapter adapter = getElementAdapter();
int c = collection.size();
writeInt(out, c);
int cActual = 0;
for (Iterator iter = collection.iterator(); iter.hasNext(); )
{
Object oElement = iter.next();
boolean fExists = (oElement != null);
out.writeBoolean(fExists);
if (fExists)
{
adapter.writeExternal(out, oElement);
}
++cActual;
}
if (c != cActual)
{
throw new IOException("expected " + c + " elements, but wrote " + cActual);
}
}
// ----- PropertyAdapter methods ----------------------------------------
/**
* Determine if the specified value is empty.
*
* @param o the value
*
* @return true if the object is considered to be empty for persistence
* and XML-generation purposes
*/
public boolean isEmpty(Object o)
{
return o == null || isEmptyIsNull() && ((Collection) o).isEmpty();
}
// ----- internal helpers -----------------------------------------------
/**
* @return a PropertyAdapter for collection elements
*/
public PropertyAdapter getElementAdapter()
{
return m_adapterElement;
}
/**
* @return a new Collection instance
*/
protected Collection instantiateCollection()
{
try
{
return (Collection) m_clzCollection.newInstance();
}
catch (Throwable e)
{
throw ensureRuntimeException(e);
}
}
// ----- data members ---------------------------------------------------
private Class m_clzCollection;
private PropertyAdapter m_adapterElement;
}
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