/*
* Copyright 2017 The GDL Authors
*
* 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.s1ck.gdl;
import org.antlr.v4.runtime.ANTLRErrorStrategy;
import org.antlr.v4.runtime.ANTLRFileStream;
import org.antlr.v4.runtime.ANTLRInputStream;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.DefaultErrorStrategy;
import org.antlr.v4.runtime.tree.ParseTreeWalker;
import org.s1ck.gdl.model.Edge;
import org.s1ck.gdl.model.Graph;
import org.s1ck.gdl.model.Vertex;
import org.s1ck.gdl.model.predicates.Predicate;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;
import java.util.Map;
import java.util.Optional;
/**
* Helper class that wraps ANTLR initialization logic.
*/
public class GDLHandler {
/**
* GDL listener implementation.
*/
private GDLLoader loader;
/**
* Private constructor to avoid external initialization.
*
* @param loader GDL loader
*/
private GDLHandler(GDLLoader loader) {
this.loader = loader;
}
/**
* Append the given GDL string to the current database.
*
* @param asciiString GDL string (must not be {@code null}).
*/
public void append(String asciiString) {
if (asciiString == null) {
throw new IllegalArgumentException("AsciiString must not be null");
}
ANTLRInputStream antlrInputStream = new ANTLRInputStream(asciiString);
GDLLexer lexer = new GDLLexer(antlrInputStream);
GDLParser parser = new GDLParser(new CommonTokenStream(lexer));
// update the loader state while walking the parse tree
new ParseTreeWalker().walk(loader, parser.database());
}
/**
* Returns a collection of all graphs defined in the GDL script.
*
* @return graph collection
*/
public Collection<Graph> getGraphs() {
return loader.getGraphs();
}
/**
* Returns a collection of all vertices defined in the GDL script.
*
* @return vertex collection
*/
public Collection<Vertex> getVertices() {
return loader.getVertices();
}
/**
* Returns a collection of all edges defined in the GDL script.
*
* @return edge collection
*/
public Collection<Edge> getEdges() {
return loader.getEdges();
}
/**
* Returns the predicates defined by the query in CNF.
*
* @return predicates
*/
public Optional<Predicate> getPredicates() { return loader.getPredicates(); }
/**
* Returns a cache that contains a mapping from user-defined variables to graph instances.
*
* @return immutable graph cache
*/
public Map<String, Graph> getGraphCache() {
return loader.getGraphCache();
}
/**
* Returns a cache that contains a mapping from variables to graph instances.
*
* @param includeUserDefined true, iff user-defined variables shall be included in the cache
* @param includeAutoGenerated true, iff auto-generated variables shall be included in the cache
*
* @return immutable graph cache
*/
public Map<String, Graph> getGraphCache(boolean includeUserDefined, boolean includeAutoGenerated) {
return loader.getGraphCache(includeUserDefined, includeAutoGenerated);
}
/**
* Returns a cache that contains a mapping from user-defined variables to vertex instances.
*
* @return immutable vertex cache
*/
public Map<String, Vertex> getVertexCache() {
return loader.getVertexCache();
}
/**
* Returns a cache that contains a mapping from variables to vertex instances.
*
* @param includeUserDefined true, iff user-defined variables shall be included in the cache
* @param includeAutoGenerated true, iff auto-generated variables shall be included in the cache
*
* @return immutable vertex cache
*/
public Map<String, Vertex> getVertexCache(boolean includeUserDefined, boolean includeAutoGenerated) {
return loader.getVertexCache(includeUserDefined, includeAutoGenerated);
}
/**
* Returns a cache that contains a mapping from user-defined variables to edge instances.
*
* @return immutable edge cache
*/
public Map<String, Edge> getEdgeCache() {
return loader.getEdgeCache();
}
/**
* Returns a cache that contains a mapping from variables to edge instances.
*
* @param includeUserDefined true, iff user-defined variables shall be included in the cache
* @param includeAutoGenerated true, iff auto-generated variables shall be included in the cache
*
* @return immutable edge cache
*/
public Map<String, Edge> getEdgeCache(boolean includeUserDefined, boolean includeAutoGenerated) {
return loader.getEdgeCache(includeUserDefined, includeAutoGenerated);
}
/**
* Builds a GDL Handler.
*/
public static class Builder {
/**
* Graph label.
*/
private String graphLabel = "__GRAPH";
/**
* Vertex label.
*/
private String vertexLabel = "__VERTEX";
/**
* Edge label.
*/
private String edgeLabel = "__EDGE";
/**
* Flag to indicate if the default graph label shall be used if none is present.
*/
private boolean useDefaultGraphLabel = true;
/**
* Flag to indicate if the default vertex label shall be used if none is present.
*/
private boolean useDefaultVertexLabel = true;
/**
* Flag to indicate if the default edge label shall be used if none is present.
*/
private boolean useDefaultEdgeLabel = true;
/**
* Strategy for handling parser errors.
*/
private ANTLRErrorStrategy errorStrategy = new DefaultErrorStrategy();
/**
* Default graph label is used if none is set in the GDL script.
*
* @param graphLabel graph label (must not be {@code null}).
* @return builder
*/
public Builder setDefaultGraphLabel(String graphLabel) {
this.graphLabel = graphLabel;
return this;
}
/**
* Default vertex label is used if none is set in the GDL script.
*
* @param vertexLabel vertex label (must not be {@code null}).
* @return builder
*/
public Builder setDefaultVertexLabel(String vertexLabel) {
this.vertexLabel = vertexLabel;
return this;
}
/**
* Default edge label is used if none is set in the GDL script.
*
* @param edgeLabel edge label (must not be {@code null}).
* @return builder
*/
public Builder setDefaultEdgeLabel(String edgeLabel) {
this.edgeLabel = edgeLabel;
return this;
}
/**
* Enable default graph label.
*
* @return builder
*/
public Builder enableDefaultGraphLabel() {
this.useDefaultGraphLabel = true;
return this;
}
/**
* Disable default graph label.
*
* @return builder
*/
public Builder disableDefaultGraphLabel() {
this.useDefaultGraphLabel = false;
return this;
}
/**
* Enable default vertex label.
*
* @return builder
*/
public Builder enableDefaultVertexLabel() {
this.useDefaultVertexLabel = true;
return this;
}
/**
* Disable default vertex label.
*
* @return builder
*/
public Builder disableDefaultVertexLabel() {
this.useDefaultVertexLabel = false;
return this;
}
/**
* Enable default edge label.
*
* @return builder
*/
public Builder enableDefaultEdgeLabel() {
this.useDefaultEdgeLabel = true;
return this;
}
/**
* Disable default edge label.
*
* @return builder
*/
public Builder disableDefaultEdgeLabel() {
this.useDefaultEdgeLabel = false;
return this;
}
/**
* Set the error handler strategy for ANTLR. If not set, {@link DefaultErrorStrategy} is used.
*
* @param errorStrategy ANTLR error strategy
* @return builder
*/
public Builder setErrorStrategy(ANTLRErrorStrategy errorStrategy) {
this.errorStrategy = errorStrategy;
return this;
}
/**
* Initialize GDL Handler from given ASCII String.
*
* @param asciiString GDL string (must not be {@code null}).
* @return GDL handler
*/
public GDLHandler buildFromString(String asciiString) {
ANTLRInputStream antlrInputStream = new ANTLRInputStream(asciiString);
return build(antlrInputStream);
}
/**
* Initializes GDL Handler from given input stream.
*
* @param stream InputStream (must not be {@code null}).
* @return GDL handler
* @throws IOException
*/
public GDLHandler buildFromStream(InputStream stream) throws IOException {
ANTLRInputStream antlrInputStream = new ANTLRInputStream(stream);
return build(antlrInputStream);
}
/**
* Initializes GDL Handler from given file.
*
* @param fileName GDL file (must not be {@code null}).
* @return GDL handler
*/
public GDLHandler buildFromFile(String fileName) throws IOException {
ANTLRInputStream antlrInputStream = new ANTLRFileStream(fileName);
return build(antlrInputStream);
}
/**
* Checks valid input and creates GDL Handler.
*
* @param antlrInputStream ANTLR input stream
* @return GDL handler
*/
private GDLHandler build(ANTLRInputStream antlrInputStream) {
if (graphLabel == null) {
throw new IllegalArgumentException("Graph label must not be null.");
}
if (vertexLabel == null) {
throw new IllegalArgumentException("Vertex label must not be null.");
}
if (edgeLabel == null) {
throw new IllegalArgumentException("Edge label must not be null.");
}
if (errorStrategy == null) {
throw new IllegalArgumentException("Error handler must not be null.");
}
GDLLexer lexer = new GDLLexer(antlrInputStream);
GDLParser parser = new GDLParser(new CommonTokenStream(lexer));
parser.setErrorHandler(errorStrategy);
GDLLoader loader = new GDLLoader(graphLabel, vertexLabel, edgeLabel,
useDefaultGraphLabel, useDefaultVertexLabel, useDefaultEdgeLabel);
new ParseTreeWalker().walk(loader, parser.database());
return new GDLHandler(loader);
}
}
}
