| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 |
| * |
| * https://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.apache.avro.compiler.idl; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.IdentityHashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.function.Function; |
| |
| import org.apache.avro.Protocol; |
| import org.apache.avro.Schema; |
| import org.apache.avro.compiler.schema.Schemas; |
| |
| /** |
| * Utility class to resolve schemas that are unavailable at the time they are |
| * referenced in the IDL. |
| */ |
| final class SchemaResolver { |
| |
| private SchemaResolver() { |
| } |
| |
| private static final String UR_SCHEMA_ATTR = "org.apache.avro.compiler.idl.unresolved.name"; |
| |
| private static final String UR_SCHEMA_NAME = "UnresolvedSchema"; |
| |
| private static final String UR_SCHEMA_NS = "org.apache.avro.compiler"; |
| |
| /** |
| * Create a schema to represent a "unresolved" schema. (used to represent a |
| * schema where the definition is not known at the time) This concept might be |
| * generalizable... |
| * |
| * @param name |
| * @return |
| */ |
| static Schema unresolvedSchema(final String name) { |
| Schema schema = Schema.createRecord(UR_SCHEMA_NAME, "unresolved schema", UR_SCHEMA_NS, false, |
| Collections.EMPTY_LIST); |
| schema.addProp(UR_SCHEMA_ATTR, name); |
| return schema; |
| } |
| |
| /** |
| * Is this a unresolved schema. |
| * |
| * @param schema |
| * @return |
| */ |
| static boolean isUnresolvedSchema(final Schema schema) { |
| return (schema.getType() == Schema.Type.RECORD && schema.getProp(UR_SCHEMA_ATTR) != null |
| && UR_SCHEMA_NAME.equals(schema.getName()) && UR_SCHEMA_NS.equals(schema.getNamespace())); |
| } |
| |
| /** |
| * get the unresolved schema name. |
| * |
| * @param schema |
| * @return |
| */ |
| static String getUnresolvedSchemaName(final Schema schema) { |
| if (!isUnresolvedSchema(schema)) { |
| throw new IllegalArgumentException("Not a unresolved schema: " + schema); |
| } |
| return schema.getProp(UR_SCHEMA_ATTR); |
| } |
| |
| /** |
| * Is this a unresolved schema. |
| * |
| * @param schema |
| * @return |
| */ |
| static boolean isFullyResolvedSchema(final Schema schema) { |
| if (isUnresolvedSchema(schema)) { |
| return false; |
| } else { |
| return Schemas.visit(schema, new IsResolvedSchemaVisitor()); |
| } |
| } |
| |
| /** |
| * Will clone the provided protocol while resolving all unreferenced schemas |
| * |
| * @param protocol |
| * @return |
| */ |
| static Protocol resolve(final Protocol protocol) { |
| Protocol result = new Protocol(protocol.getName(), protocol.getDoc(), protocol.getNamespace()); |
| final Collection<Schema> types = protocol.getTypes(); |
| // replace unresolved schemas. |
| List<Schema> newSchemas = new ArrayList<>(types.size()); |
| IdentityHashMap<Schema, Schema> replacements = new IdentityHashMap<>(); |
| for (Schema schema : types) { |
| newSchemas.add(Schemas.visit(schema, new ResolvingVisitor(schema, replacements, new SymbolTable(protocol)))); |
| } |
| result.setTypes(newSchemas); // replace types with resolved ones |
| |
| // Resolve all schemas referenced by protocol Messages. |
| for (Map.Entry<String, Protocol.Message> entry : protocol.getMessages().entrySet()) { |
| Protocol.Message value = entry.getValue(); |
| Protocol.Message nvalue; |
| if (value.isOneWay()) { |
| Schema replacement = resolve(replacements, value.getRequest(), protocol); |
| nvalue = result.createMessage(value.getName(), value.getDoc(), value, replacement); |
| } else { |
| Schema request = resolve(replacements, value.getRequest(), protocol); |
| Schema response = resolve(replacements, value.getResponse(), protocol); |
| Schema errors = resolve(replacements, value.getErrors(), protocol); |
| nvalue = result.createMessage(value.getName(), value.getDoc(), value, request, response, errors); |
| } |
| result.getMessages().put(entry.getKey(), nvalue); |
| } |
| Schemas.copyProperties(protocol, result); |
| return result; |
| } |
| |
| private static Schema resolve(final IdentityHashMap<Schema, Schema> replacements, final Schema request, |
| final Protocol protocol) { |
| Schema replacement = replacements.get(request); |
| if (replacement == null) { |
| replacement = Schemas.visit(request, new ResolvingVisitor(request, replacements, new SymbolTable(protocol))); |
| } |
| return replacement; |
| } |
| |
| private static class SymbolTable implements Function<String, Schema> { |
| |
| private final Protocol symbolTable; |
| |
| public SymbolTable(Protocol symbolTable) { |
| this.symbolTable = symbolTable; |
| } |
| |
| @Override |
| public Schema apply(final String f) { |
| return symbolTable.getType(f); |
| } |
| } |
| |
| } |