org.simpleframework.xml.strategy.WriteState Maven / Gradle / Ivy
/*
* WriteState.java April 2007
*
* Copyright (C) 2007, Niall Gallagher
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307 USA
*/
package org.simpleframework.xml.strategy;
import org.simpleframework.xml.util.WeakCache;
/**
* The WriteState object is used to store all graphs that
* are currently been written with a given cycle strategy. The goal of
* this object is to act as a temporary store for graphs such that
* when the persistence session has completed the write graph will be
* garbage collected. This ensures that there are no lingering object
* reference that could cause a memory leak. If a graph for the given
* session key does not exist then a new one is created.
*
* @author Niall Gallagher
*
* @see org.simpleframework.xml.strategy.WriteGraph
*/
class WriteState extends WeakCache {
/**
* This is the contract that specifies the attributes to use.
*/
private Contract contract;
/**
* Constructor for the WriteState object. This is
* used to create graphs that are used for writing objects to the
* the XML document. The specified strategy is used to acquire the
* names of the special attributes used during the serialization.
*
* @param contract this is the name scheme used by the strategy
*/
public WriteState(Contract contract) {
this.contract = contract;
}
/**
* This will acquire the graph using the specified session map. If
* a graph does not already exist mapped to the given session then
* one will be created and stored with the key provided. Once the
* specified key is garbage collected then so is the graph object.
*
* @param map this is typically the persistence session map used
*
* @return returns a graph used for writing the XML document
*/
public WriteGraph find(Object map) {
WriteGraph write = fetch(map);
if(write == null) {
write = new WriteGraph(contract);
cache(map, write);
}
return write;
}
}