org.prebake.service.DotRenderer.java Source code

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Here is the source code for org.prebake.service.DotRenderer.java

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// Copyright 2010, Mike Samuel
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.prebake.service;

import org.prebake.core.BoundName;
import org.prebake.service.plan.PlanGraph;

import com.google.common.base.Function;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;

import java.io.IOError;
import java.io.IOException;
import java.util.List;
import java.util.Set;

import javax.annotation.ParametersAreNonnullByDefault;

/**
 * Converts a plan graph to
 * <a href="http://www.graphviz.org/doc/info/lang.html">DOT format</a>.
 *
 * @author Mike Samuel <mikesamuel@gmail.com>
 */
@ParametersAreNonnullByDefault
final class DotRenderer {
    static void render(final PlanGraph g, final Set<BoundName> prods, final Appendable out) throws IOException {
        final List<BoundName> roots = Lists.newArrayList(prods);
        // Eliminate any products that are dependencies of others.
        {
            final Set<BoundName> notRoots = Sets.newHashSet();
            for (final BoundName prod : prods) {
                if (notRoots.contains(prod)) {
                    break;
                }
                g.walker(new Function<BoundName, Void>() {
                    public Void apply(BoundName node) {
                        if (!node.equals(prod) && prods.contains(node)) {
                            notRoots.add(node);
                        }
                        return null;
                    }
                }).walk(prod);
            }
            roots.removeAll(notRoots);
        }
        out.append("digraph {\n");
        for (BoundName root : roots) {
            try {
                g.walker(new Function<BoundName, Void>() {
                    public Void apply(BoundName node) {
                        try {
                            out.append("  ");
                            writeDotId(node.ident);
                            out.append(";\n");
                            for (BoundName dep : g.edges.get(node)) {
                                out.append("  ");
                                writeDotId(dep.ident);
                                out.append(" -> ");
                                writeDotId(node.ident);
                                out.append(";\n");
                            }
                            // TODO: display intersection of inputs and outputs at edge
                            // to help debug
                        } catch (IOException ex) {
                            throw new IOError(ex);
                        }
                        return null;
                    }

                    private void writeDotId(String id) throws IOException {
                        out.append('"');
                        out.append(id.replaceAll("[\\\\\"]", "\\\\$0"));
                        out.append('"');
                    }
                }).walk(root);
            } catch (IOError err) {
                throw (IOException) err.getCause();
            }
        }
        out.append("}\n");
    }
}