| /* |
| * 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 |
| * |
| * 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.apache.calcite.util; |
| |
| import org.apache.calcite.avatica.util.Spaces; |
| |
| import com.google.common.collect.ImmutableList; |
| |
| import org.checkerframework.checker.nullness.qual.Nullable; |
| |
| import java.util.ArrayList; |
| import java.util.LinkedHashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * Builder for JSON documents (represented as {@link List}, {@link Map}, |
| * {@link String}, {@link Boolean}, {@link Long}). |
| */ |
| public class JsonBuilder { |
| /** Maps control characters (0 .. 31) to JSON escaped strings. |
| * Tab, newline, form feed and carriage return are mapped to '\t', '\n', |
| * '\f', 'r' respectively; others are mapped to '\\u00xx' for some 'xx'. */ |
| private static final ImmutableList<String> ESCAPED = ImmutableList.of( |
| "\\u0000", |
| "\\u0001", |
| "\\u0002", |
| "\\u0003", |
| "\\u0004", |
| "\\u0005", |
| "\\u0006", |
| "\\u0007", |
| "\\u0008", |
| "\\t", // tab, ASCII 9 x09 |
| "\\n", // newline, ASCII 10 x0A |
| "\\u000B", |
| "\\f", // form feed, ASCII 12 x0C |
| "\\r", // carriage return, ASCII 13 x0D |
| "\\u000E", |
| "\\u000F", |
| "\\u0010", |
| "\\u0011", |
| "\\u0012", |
| "\\u0013", |
| "\\u0014", |
| "\\u0015", |
| "\\u0016", |
| "\\u0017", |
| "\\u0018", |
| "\\u0019", |
| "\\u001A", |
| "\\u001B", |
| "\\u001C", |
| "\\u001D", |
| "\\u001E", |
| "\\u001F"); |
| |
| /** |
| * Creates a JSON object (represented by a {@link Map}). |
| */ |
| public Map<String, @Nullable Object> map() { |
| // Use LinkedHashMap to preserve order. |
| return new LinkedHashMap<>(); |
| } |
| |
| /** |
| * Creates a JSON object (represented by a {@link List}). |
| */ |
| public List<@Nullable Object> list() { |
| return new ArrayList<>(); |
| } |
| |
| /** |
| * Adds a key/value pair to a JSON object. |
| */ |
| public JsonBuilder put(Map<String, @Nullable Object> map, String name, @Nullable Object value) { |
| map.put(name, value); |
| return this; |
| } |
| |
| /** |
| * Adds a key/value pair to a JSON object if the value is not null. |
| */ |
| public JsonBuilder putIf( |
| Map<String, @Nullable Object> map, String name, @Nullable Object value) { |
| if (value != null) { |
| map.put(name, value); |
| } |
| return this; |
| } |
| |
| /** |
| * Serializes an object consisting of maps, lists and atoms into a JSON |
| * string. |
| * |
| * <p>We should use a JSON library such as Jackson when Mondrian needs |
| * one elsewhere.</p> |
| */ |
| public String toJsonString(Object o) { |
| StringBuilder buf = new StringBuilder(); |
| append(buf, 0, o); |
| return buf.toString(); |
| } |
| |
| /** |
| * Appends a JSON object to a string builder. |
| */ |
| public void append(StringBuilder buf, int indent, @Nullable Object o) { |
| if (o == null) { |
| buf.append("null"); |
| } else if (o instanceof Map) { |
| //noinspection unchecked |
| appendMap(buf, indent, (Map) o); |
| } else if (o instanceof List) { |
| appendList(buf, indent, (List<?>) o); |
| } else if (o instanceof String) { |
| appendString(buf, (String) o); |
| } else { |
| assert o instanceof Number || o instanceof Boolean; |
| buf.append(o); |
| } |
| } |
| |
| private static void appendString(StringBuilder buf, String s) { |
| buf.append('"'); |
| final int n = s.length(); |
| for (int i = 0; i < n; i++) { |
| char c = s.charAt(i); |
| if (c < 32) { |
| buf.append(ESCAPED.get(c)); |
| } else if (c == '\\') { |
| buf.append("\\\\"); |
| } else if (c == '"') { |
| buf.append("\\\""); |
| } else { |
| buf.append(c); |
| } |
| } |
| buf.append('"'); |
| } |
| |
| private void appendMap( |
| StringBuilder buf, int indent, Map<String, @Nullable Object> map) { |
| if (map.isEmpty()) { |
| buf.append("{}"); |
| return; |
| } |
| buf.append("{"); |
| newline(buf, indent + 1); |
| int n = 0; |
| for (Map.Entry<String, @Nullable Object> entry : map.entrySet()) { |
| if (n++ > 0) { |
| buf.append(","); |
| newline(buf, indent + 1); |
| } |
| append(buf, 0, entry.getKey()); |
| buf.append(": "); |
| append(buf, indent + 1, entry.getValue()); |
| } |
| newline(buf, indent); |
| buf.append("}"); |
| } |
| |
| private static void newline(StringBuilder buf, int indent) { |
| Spaces.append(buf.append('\n'), indent * 2); |
| } |
| |
| private void appendList( |
| StringBuilder buf, int indent, List<?> list) { |
| if (list.isEmpty()) { |
| buf.append("[]"); |
| return; |
| } |
| buf.append("["); |
| newline(buf, indent + 1); |
| int n = 0; |
| for (Object o : list) { |
| if (n++ > 0) { |
| buf.append(","); |
| newline(buf, indent + 1); |
| } |
| append(buf, indent + 1, o); |
| } |
| newline(buf, indent); |
| buf.append("]"); |
| } |
| } |