Java tutorial
/* [BSD 3-Clause License] Copyright (c) 2017, PayPal Holdings, Inc. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package com.paypal.digraph.parser; import java.io.InputStream; import java.util.BitSet; import java.util.Map; import java.util.TreeMap; import java.util.TreeSet; import org.antlr.v4.runtime.ANTLRInputStream; import org.antlr.v4.runtime.BaseErrorListener; import org.antlr.v4.runtime.CommonTokenStream; import org.antlr.v4.runtime.DefaultErrorStrategy; import org.antlr.v4.runtime.InputMismatchException; import org.antlr.v4.runtime.Parser; import org.antlr.v4.runtime.RecognitionException; import org.antlr.v4.runtime.Recognizer; import org.antlr.v4.runtime.Token; import org.antlr.v4.runtime.atn.ATNConfigSet; import org.antlr.v4.runtime.dfa.DFA; import org.antlr.v4.runtime.misc.IntervalSet; import org.antlr.v4.runtime.misc.NotNull; import org.antlr.v4.runtime.misc.Nullable; import org.antlr.v4.runtime.tree.ParseTree; import org.antlr.v4.runtime.tree.ParseTreeWalker; import org.antlr.v4.runtime.tree.TerminalNode; import com.paypal.digraph.parser.antlr.DOTBaseListener; import com.paypal.digraph.parser.antlr.DOTLexer; import com.paypal.digraph.parser.antlr.DOTParser; import com.paypal.digraph.parser.antlr.DOTParser.A_listContext; import com.paypal.digraph.parser.antlr.DOTParser.IdContext; public class GraphParser { private Map<String, GraphNode> mNodeMap = new TreeMap<String, GraphNode>(); private Map<String, GraphEdge> mEdgeMap = new TreeMap<String, GraphEdge>(); private String mGraphId; private String mErrMsg; public GraphParser(InputStream is) throws GraphParserException { DOTLexer lexer = null; DOTParser parser = null; try { lexer = new DOTLexer(new ANTLRInputStream(is)); lexer.addErrorListener(new ErrorListener()); parser = new DOTParser(new CommonTokenStream(lexer)); parser.setErrorHandler(new ExceptionErrorStrategy()); parser.addErrorListener(new ErrorListener()); ParseTree tree = parser.graph(); ParseTreeWalker.DEFAULT.walk(new NodeListener(), tree); ParseTreeWalker.DEFAULT.walk(new EdgeListener(), tree); } catch (Throwable t) { if (mErrMsg != null) throw new GraphParserException(mErrMsg, t); if (lexer != null) { mErrMsg = "at line " + lexer.getLine() + ":" + lexer.getCharPositionInLine(); throw new GraphParserException(mErrMsg, t); } throw new GraphParserException(t); } if (mErrMsg != null) throw new GraphParserException(mErrMsg); } public Map<String, GraphNode> getNodes() { return mNodeMap; } public Map<String, GraphEdge> getEdges() { return mEdgeMap; } public String getGraphId() { return mGraphId; } /* * NodeListener */ private class NodeListener extends DOTBaseListener { Map<String, Object> nodeAttrs = new TreeMap<String, Object>(); /*@Override*/ public void enterGraph(@NotNull DOTParser.GraphContext ctx) { if (ctx.id() != null) mGraphId = ctx.id().getText(); } /*@Override*/ public void exitGraph(@NotNull DOTParser.GraphContext ctx) { // no-op } /*@Override*/ public void enterNode_id(@NotNull DOTParser.Node_idContext ctx) { String nodeId = ctx.id().getText(); GraphNode node = mNodeMap.get(nodeId); if (node == null) { node = new GraphNode(nodeId); mNodeMap.put(nodeId, node); } node.setAttributes(nodeAttrs); } /*@Override*/ public void exitNode_id(@NotNull DOTParser.Node_idContext ctx) { // no-op } /*@Override*/ public void enterNode_stmt(@NotNull DOTParser.Node_stmtContext ctx) { populateAttributes(ctx.attr_list(), nodeAttrs); } /*@Override*/ public void exitNode_stmt(@NotNull DOTParser.Node_stmtContext ctx) { nodeAttrs.clear(); } } /* * EdgeListener */ private class EdgeListener extends DOTBaseListener { GraphCtx graphCtx = new GraphCtx(null); EdgeCtx edgeCtx; /*@Override*/ public void enterNode_id(@NotNull DOTParser.Node_idContext ctx) { String nodeId = ctx.id().getText(); graphCtx.addNode(nodeId); } /*@Override*/ public void exitNode_id(@NotNull DOTParser.Node_idContext ctx) { // no-op } /*@Override*/ public void enterSubgraph(@NotNull DOTParser.SubgraphContext ctx) { // enter new nested subgraph ctx graphCtx = new GraphCtx(graphCtx); } /*@Override*/ public void exitSubgraph(@NotNull DOTParser.SubgraphContext ctx) { // leave nested ctx, pop previous parent ctx graphCtx = graphCtx.parent; } /*@Override*/ public void enterEdge_stmt(@NotNull DOTParser.Edge_stmtContext ctx) { // enter new nested edge ctx edgeCtx = new EdgeCtx(edgeCtx, new GraphCtx(graphCtx), new GraphCtx(graphCtx), ctx.attr_list()); graphCtx = edgeCtx.src; // point to src, next node/subgraph populates it } /*@Override*/ public void exitEdge_stmt(@NotNull DOTParser.Edge_stmtContext ctx) { addEdges(edgeCtx.src.graph, edgeCtx.dest.graph, edgeCtx.attrs); // leave nested ctx, pop previous parent ctx edgeCtx = edgeCtx.parent; graphCtx = graphCtx.parent; } /*@Override*/ public void enterEdgeop(@NotNull DOTParser.EdgeopContext ctx) { addEdges(edgeCtx.src.graph, edgeCtx.dest.graph, edgeCtx.attrs); if (edgeCtx.srcFlag) { // pointing to src, shift to populate dest graphCtx = edgeCtx.dest; edgeCtx.srcFlag = false; } else { // pointing to dest already, shift src/dest for next edgeop edgeCtx.src = edgeCtx.dest; edgeCtx.dest = new GraphCtx(graphCtx.parent); graphCtx = edgeCtx.dest; } } /*@Override*/ public void exitEdgeop(@NotNull DOTParser.EdgeopContext ctx) { // no-op } private void addEdges(NodeIdSet srcSet, NodeIdSet destSet, Map<String, Object> attrs) { for (String src : srcSet) { for (String dest : destSet) { addEdge(src, dest, attrs); } } } private void addEdge(String nodeId1, String nodeId2, Map<String, Object> attrs) { String edgeId = nodeId1 + "-" + nodeId2; GraphEdge edge = mEdgeMap.get(edgeId); if (edge == null) { GraphNode node1 = mNodeMap.get(nodeId1); GraphNode node2 = mNodeMap.get(nodeId2); edge = new GraphEdge(edgeId, node1, node2); mEdgeMap.put(edgeId, edge); } edge.setAttributes(attrs); } } /* * NodeIdSet */ private class NodeIdSet extends TreeSet<String> { public NodeIdSet() { super(); } public NodeIdSet(NodeIdSet other) { super(other); } } /* * GraphCtx */ private class GraphCtx { GraphCtx parent; NodeIdSet graph = new NodeIdSet(); GraphCtx(GraphCtx parent) { this.parent = parent; } void addNode(String nodeId) { graph.add(nodeId); if (parent != null) parent.addNode(nodeId); } public String toString() { return graph.toString(); } } /* * EdgeCtx */ private class EdgeCtx { EdgeCtx parent; GraphCtx src; GraphCtx dest; boolean srcFlag = true; Map<String, Object> attrs = new TreeMap<String, Object>(); EdgeCtx(EdgeCtx parent, GraphCtx src, GraphCtx dest, DOTParser.Attr_listContext ctx) { this.parent = parent; this.src = src; this.dest = dest; populateAttributes(ctx, attrs); } public String toString() { return src + "->" + dest; } } /* * populateAttributes helper */ private void populateAttributes(DOTParser.Attr_listContext ctx, Map<String, Object> attrs) { attrs.clear(); if (ctx == null) return; for (A_listContext listCtx : ctx.a_list()) { String[] kv = { null, null }; int i = 0; for (IdContext idCtx : listCtx.id()) { TerminalNode idObj = idCtx.ID(); if (idObj == null) idObj = idCtx.NUMBER(); if (idObj == null) idObj = idCtx.STRING(); if (idObj == null) idObj = idCtx.HTML_STRING(); String text = idObj.getText(); if (idObj.getSymbol().getType() == DOTParser.STRING) { text = trimDoubleQuotes(text); text = text.replace("\\\"", "\""); } kv[i++] = text; if (i > 1) { attrs.put(kv[0], kv[1]); i = 0; } } } } private static String trimDoubleQuotes(String text) { int textLength = text.length(); if (textLength >= 2 && text.charAt(0) == '"' && text.charAt(textLength - 1) == '"') { return text.substring(1, textLength - 1); } return text; } /* * ErrorListener */ private class ErrorListener extends BaseErrorListener { public void syntaxError(@NotNull Recognizer<?, ?> recognizer, @Nullable Object offendingSymbol, int line, int charPositionInLine, @NotNull String msg, @Nullable RecognitionException e) { mErrMsg = "at line " + line + ":" + charPositionInLine + " " + msg; throw e; } @Override public void reportAmbiguity(@NotNull Parser recognizer, @NotNull DFA dfa, int startIndex, int stopIndex, boolean exact, @Nullable BitSet ambigAlts, @NotNull ATNConfigSet configs) { } @Override public void reportAttemptingFullContext(@NotNull Parser recognizer, @NotNull DFA dfa, int startIndex, int stopIndex, @Nullable BitSet conflictingAlts, @NotNull ATNConfigSet configs) { } @Override public void reportContextSensitivity(@NotNull Parser recognizer, @NotNull DFA dfa, int startIndex, int stopIndex, int prediction, @NotNull ATNConfigSet configs) { } } /* * ExceptionErrorStrategy */ private class ExceptionErrorStrategy extends DefaultErrorStrategy { @Override public void recover(Parser recognizer, RecognitionException e) { throw e; } @Override public void reportInputMismatch(Parser recognizer, InputMismatchException e) throws RecognitionException { String msg = "mismatched input " + getTokenErrorDisplay(e.getOffendingToken()); msg += " expecting one of " + e.getExpectedTokens().toString(recognizer.getTokenNames()); RecognitionException ex = new RecognitionException(msg, recognizer, recognizer.getInputStream(), recognizer.getContext()); ex.initCause(e); throw ex; } @Override public void reportMissingToken(Parser recognizer) { beginErrorCondition(recognizer); Token t = recognizer.getCurrentToken(); IntervalSet expecting = getExpectedTokens(recognizer); String msg = "missing " + expecting.toString(recognizer.getTokenNames()) + " at " + getTokenErrorDisplay(t); throw new RecognitionException(msg, recognizer, recognizer.getInputStream(), recognizer.getContext()); } } private static void log(Object o) { System.out.println(o); } }