/*
* Copyright (C) 2011 Google Inc.
*
* 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 com.google.inject.grapher;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import com.google.inject.Binding;
import com.google.inject.Injector;
import com.google.inject.Key;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* Abstract injector grapher that builds the dependency graph but doesn't render it.
*
* @author bojand@google.com (Bojan Djordjevic)
* @since 4.0
*/
public abstract class AbstractInjectorGrapher implements InjectorGrapher {
private final RootKeySetCreator rootKeySetCreator;
private final AliasCreator aliasCreator;
private final NodeCreator nodeCreator;
private final EdgeCreator edgeCreator;
/**
* Parameters used to override default settings of the grapher.
*
* @since 4.0
*/
public static final class GrapherParameters {
private RootKeySetCreator rootKeySetCreator = new DefaultRootKeySetCreator();
private AliasCreator aliasCreator = new ProviderAliasCreator();
private NodeCreator nodeCreator = new DefaultNodeCreator();
private EdgeCreator edgeCreator = new DefaultEdgeCreator();
public RootKeySetCreator getRootKeySetCreator() {
return rootKeySetCreator;
}
public GrapherParameters setRootKeySetCreator(RootKeySetCreator rootKeySetCreator) {
this.rootKeySetCreator = rootKeySetCreator;
return this;
}
public AliasCreator getAliasCreator() {
return aliasCreator;
}
public GrapherParameters setAliasCreator(AliasCreator aliasCreator) {
this.aliasCreator = aliasCreator;
return this;
}
public NodeCreator getNodeCreator() {
return nodeCreator;
}
public GrapherParameters setNodeCreator(NodeCreator nodeCreator) {
this.nodeCreator = nodeCreator;
return this;
}
public EdgeCreator getEdgeCreator() {
return edgeCreator;
}
public GrapherParameters setEdgeCreator(EdgeCreator edgeCreator) {
this.edgeCreator = edgeCreator;
return this;
}
}
public AbstractInjectorGrapher() {
this(new GrapherParameters());
}
public AbstractInjectorGrapher(GrapherParameters options) {
this.rootKeySetCreator = options.getRootKeySetCreator();
this.aliasCreator = options.getAliasCreator();
this.nodeCreator = options.getNodeCreator();
this.edgeCreator = options.getEdgeCreator();
}
@Override
public final void graph(Injector injector) throws IOException {
graph(injector, rootKeySetCreator.getRootKeys(injector));
}
@Override
public final void graph(Injector injector, Set<Key<?>> root) throws IOException {
reset();
Iterable<Binding<?>> bindings = getBindings(injector, root);
Map<NodeId, NodeId> aliases = resolveAliases(aliasCreator.createAliases(bindings));
createNodes(nodeCreator.getNodes(bindings), aliases);
createEdges(edgeCreator.getEdges(bindings), aliases);
postProcess();
}
/** Resets the state of the grapher before rendering a new graph. */
protected abstract void reset() throws IOException;
/** Adds a new interface node to the graph. */
protected abstract void newInterfaceNode(InterfaceNode node) throws IOException;
/** Adds a new implementation node to the graph. */
protected abstract void newImplementationNode(ImplementationNode node) throws IOException;
/** Adds a new instance node to the graph. */
protected abstract void newInstanceNode(InstanceNode node) throws IOException;
/** Adds a new dependency edge to the graph. */
protected abstract void newDependencyEdge(DependencyEdge edge) throws IOException;
/** Adds a new binding edge to the graph. */
protected abstract void newBindingEdge(BindingEdge edge) throws IOException;
/** Performs any post processing required after all nodes and edges have been added. */
protected abstract void postProcess() throws IOException;
private void createNodes(Iterable<Node> nodes, Map<NodeId, NodeId> aliases) throws IOException {
for (Node node : nodes) {
NodeId originalId = node.getId();
NodeId resolvedId = resolveAlias(aliases, originalId);
node = node.copy(resolvedId);
// Only render nodes that aren't aliased to some other node.
if (resolvedId.equals(originalId)) {
if (node instanceof InterfaceNode) {
newInterfaceNode((InterfaceNode) node);
} else if (node instanceof ImplementationNode) {
newImplementationNode((ImplementationNode) node);
} else {
newInstanceNode((InstanceNode) node);
}
}
}
}
private void createEdges(Iterable<Edge> edges, Map<NodeId, NodeId> aliases) throws IOException {
for (Edge edge : edges) {
edge =
edge.copy(resolveAlias(aliases, edge.getFromId()), resolveAlias(aliases, edge.getToId()));
if (!edge.getFromId().equals(edge.getToId())) {
if (edge instanceof BindingEdge) {
newBindingEdge((BindingEdge) edge);
} else {
newDependencyEdge((DependencyEdge) edge);
}
}
}
}
private NodeId resolveAlias(Map<NodeId, NodeId> aliases, NodeId nodeId) {
return aliases.containsKey(nodeId) ? aliases.get(nodeId) : nodeId;
}
/**
* Transitively resolves aliases. Given aliases (X to Y) and (Y to Z), it will return mappings (X
* to Z) and (Y to Z).
*/
private Map<NodeId, NodeId> resolveAliases(Iterable<Alias> aliases) {
Map<NodeId, NodeId> resolved = Maps.newHashMap();
Map<NodeId, Set<NodeId>> inverse = Maps.newHashMap();
for (Alias alias : aliases) {
NodeId from = alias.getFromId();
NodeId to = alias.getToId();
if (resolved.containsKey(to)) {
to = resolved.get(to);
}
resolved.put(from, to);
if (inverse.get(to) == null) {
inverse.put(to, Sets.<NodeId>newHashSet());
}
inverse.get(to).add(from);
Set<NodeId> prev = inverse.get(from);
if (prev != null) {
for (NodeId id : prev) {
resolved.remove(id);
inverse.get(from).remove(id);
resolved.put(id, to);
inverse.get(to).add(id);
}
}
}
return resolved;
}
/** Returns the bindings for the root keys and their transitive dependencies. */
private Iterable<Binding<?>> getBindings(Injector injector, Set<Key<?>> root) {
Set<Key<?>> keys = Sets.newHashSet(root);
Set<Key<?>> visitedKeys = Sets.newHashSet();
List<Binding<?>> bindings = Lists.newArrayList();
TransitiveDependencyVisitor keyVisitor = new TransitiveDependencyVisitor();
while (!keys.isEmpty()) {
Iterator<Key<?>> iterator = keys.iterator();
Key<?> key = iterator.next();
iterator.remove();
if (!visitedKeys.contains(key)) {
Binding<?> binding = injector.getBinding(key);
bindings.add(binding);
visitedKeys.add(key);
keys.addAll(binding.acceptTargetVisitor(keyVisitor));
}
}
return bindings;
}
}