/** * Create the graph used to hold the deductions. Can be overridden by subclasses that need special * purpose graph implementations here. Assumes the graph underlying fdeductions and associated * SafeGraph wrapper can be reused if present thus enabling preservation of listeners. */ protected Graph createDeductionsGraph() { if (fdeductions != null) { Graph dg = fdeductions.getGraph(); if (dg != null) { // Reuse the old graph in order to preserve any listeners safeDeductions.clear(); return dg; } } Graph dg = Factory.createGraphMem(); safeDeductions = new SafeGraph(dg); return dg; }