/**
* Copyright (c) 2006, Gaudenz Alder
*/
package com.mxgraph.io;
import java.util.Map;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import com.mxgraph.model.mxGraphModel.mxChildChange;
import com.mxgraph.model.mxICell;
/**
* Codec for mxChildChanges. This class is created and registered
* dynamically at load time and used implicitely via mxCodec
* and the mxCodecRegistry.
*/
public class mxChildChangeCodec extends mxObjectCodec
{
/**
* Constructs a new model codec.
*/
public mxChildChangeCodec()
{
this(new mxChildChange(), new String[] { "model", "child",
"previousIndex" }, new String[] { "parent", "previous" }, null);
}
/**
* Constructs a new model codec for the given arguments.
*/
public mxChildChangeCodec(Object template, String[] exclude,
String[] idrefs, Map<String, String> mapping)
{
super(template, exclude, idrefs, mapping);
}
/* (non-Javadoc)
* @see com.mxgraph.io.mxObjectCodec#isReference(java.lang.Object, java.lang.String, java.lang.Object, boolean)
*/
@Override
public boolean isReference(Object obj, String attr, Object value,
boolean isWrite)
{
if (attr.equals("child") && obj instanceof mxChildChange
&& (((mxChildChange) obj).getPrevious() != null || !isWrite))
{
return true;
}
return idrefs.contains(attr);
}
/* (non-Javadoc)
* @see com.mxgraph.io.mxObjectCodec#afterEncode(com.mxgraph.io.mxCodec, java.lang.Object, org.w3c.dom.Node)
*/
@Override
public Node afterEncode(mxCodec enc, Object obj, Node node)
{
if (obj instanceof mxChildChange)
{
mxChildChange change = (mxChildChange) obj;
Object child = change.getChild();
if (isReference(obj, "child", child, true))
{
// Encodes as reference (id)
mxCodec.setAttribute(node, "child", enc.getId(child));
}
else
{
// At this point, the encoder is no longer able to know which cells
// are new, so we have to encode the complete cell hierarchy and
// ignore the ones that are already there at decoding time. Note:
// This can only be resolved by moving the notify event into the
// execute of the edit.
enc.encodeCell((mxICell) child, node, true);
}
}
return node;
}
/**
* Reads the cells into the graph model. All cells are children of the root
* element in the node.
*/
public Node beforeDecode(mxCodec dec, Node node, Object into)
{
if (into instanceof mxChildChange)
{
mxChildChange change = (mxChildChange) into;
if (node.getFirstChild() != null
&& node.getFirstChild().getNodeType() == Node.ELEMENT_NODE)
{
// Makes sure the original node isn't modified
node = node.cloneNode(true);
Node tmp = node.getFirstChild();
change.setChild(dec.decodeCell(tmp, false));
Node tmp2 = tmp.getNextSibling();
tmp.getParentNode().removeChild(tmp);
tmp = tmp2;
while (tmp != null)
{
tmp2 = tmp.getNextSibling();
if (tmp.getNodeType() == Node.ELEMENT_NODE)
{
// Ignores all existing cells because those do not need
// to be re-inserted into the model. Since the encoded
// version of these cells contains the new parent, this
// would leave to an inconsistent state on the model
// (ie. a parent change without a call to
// parentForCellChanged).
String id = ((Element) tmp).getAttribute("id");
if (dec.lookup(id) == null)
{
dec.decodeCell(tmp, true);
}
}
tmp.getParentNode().removeChild(tmp);
tmp = tmp2;
}
}
else
{
String childRef = ((Element) node).getAttribute("child");
change.setChild((mxICell) dec.getObject(childRef));
}
}
return node;
}
/* (non-Javadoc)
* @see com.mxgraph.io.mxObjectCodec#afterDecode(com.mxgraph.io.mxCodec, org.w3c.dom.Node, java.lang.Object)
*/
@Override
public Object afterDecode(mxCodec dec, Node node, Object obj)
{
if (obj instanceof mxChildChange)
{
mxChildChange change = (mxChildChange) obj;
// Cells are encoded here after a complete transaction so the previous
// parent must be restored on the cell for the case where the cell was
// added. This is needed for the local model to identify the cell as a
// new cell and register the ID.
((mxICell) change.getChild()).setParent((mxICell) change
.getPrevious());
change.setPrevious(change.getParent());
change.setPreviousIndex(change.getIndex());
}
return obj;
}
}