| /* |
| * 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.brooklyn.camp.brooklyn.spi.dsl.parse; |
| |
| import java.util.Collection; |
| import java.util.List; |
| |
| import com.fasterxml.jackson.databind.annotation.JsonAppend; |
| import com.fasterxml.jackson.databind.annotation.JsonAppend.Prop; |
| import org.apache.brooklyn.util.collections.MutableList; |
| |
| public class DslParser { |
| private final String expression; |
| int index = -1; |
| |
| public DslParser(String expression) { |
| this.expression = expression; |
| } |
| |
| public synchronized Object parse() { |
| if (index>=0) |
| throw new IllegalStateException("Parser can only be used once"); |
| |
| index++; |
| Object result = next(); |
| |
| if (index < expression.length()) |
| throw new IllegalStateException("Unexpected character at position "+index+" in "+expression); |
| |
| return result; |
| } |
| |
| @SuppressWarnings("unchecked") |
| public Object next() { |
| int start = index; |
| |
| boolean isProperty = (index > 0 && (expression.charAt(index -1) == '[' )) || // for [x] syntax - indexes in lists |
| (index > 1 && (expression.charAt(index -1) == '"' && expression.charAt(index -2) == '[')) ; // for ["x"] syntax - string properties and map keys |
| if (!isProperty) { |
| skipWhitespace(); |
| if (index >= expression.length()) |
| throw new IllegalStateException("Unexpected end of expression to parse, looking for content since position " + start); |
| |
| if (expression.charAt(index) == '"') { |
| // assume a string, that is why for property syntax using [x] or ["x"], we skip this part |
| int stringStart = index; |
| index++; |
| do { |
| if (index >= expression.length()) |
| throw new IllegalStateException("Unexpected end of expression to parse, looking for close quote since position " + stringStart); |
| char c = expression.charAt(index); |
| if (c == '"') break; |
| if (c == '\\') index++; |
| index++; |
| } while (true); |
| index++; |
| return new QuotedString(expression.substring(stringStart, index)); |
| } |
| } |
| // not a string, must be a function (or chain thereof) |
| List<Object> result = new MutableList<Object>(); |
| |
| int fnStart = index; |
| isProperty = expression.charAt(fnStart) == '['; |
| if(!isProperty) { |
| do { |
| if (index >= expression.length()) |
| break; |
| char c = expression.charAt(index); |
| if (Character.isJavaIdentifierPart(c)) ; |
| // these chars also permitted |
| else if (c==':') ; |
| else if (c=='.' && expression.substring(0, index).endsWith("function")) ; // function.xxx used for some static DslAccessible functions |
| |
| // other things e.g. whitespace, parentheses, etc, beak on |
| else break; |
| index++; |
| } while (true); |
| } |
| String fn = isProperty ? "" : expression.substring(fnStart, index); |
| if (fn.length()==0 && !isProperty) |
| throw new IllegalStateException("Expected a function name or double-quoted string at position "+start); |
| skipWhitespace(); |
| |
| if (index < expression.length() && ( expression.charAt(index)=='(' || expression.charAt(index)=='[')) { |
| // collect arguments |
| int parenStart = index; |
| List<Object> args = new MutableList<>(); |
| if (expression.charAt(index)=='[') { |
| if (!fn.isEmpty()) { |
| return new PropertyAccess(fn); |
| } |
| if (expression.charAt(index +1)=='"') { index ++;} // for ["x"] syntax needs to be increased to extract the name of the property correctly |
| } |
| index ++; |
| do { |
| skipWhitespace(); |
| if (index >= expression.length()) |
| throw new IllegalStateException("Unexpected end of arguments to function '"+fn+"', no close parenthesis matching character at position "+parenStart); |
| char c = expression.charAt(index); |
| if(isProperty && c =='"') { index++; break; } // increasing the index for ["x"] syntax to account for the presence of the '"' |
| if (c==')'|| c == ']') break; |
| if (c==',') { |
| if (args.isEmpty()) |
| throw new IllegalStateException("Invalid character at position"+index); |
| index++; |
| } else { |
| if (!args.isEmpty() && !isProperty) |
| throw new IllegalStateException("Expected , before position"+index); |
| } |
| args.add(next()); // call with first letter of the property |
| } while (true); |
| |
| if (fn.isEmpty()) { |
| Object arg = args.get(0); |
| if (arg instanceof PropertyAccess) { |
| result.add(arg); |
| } else if (arg instanceof FunctionWithArgs) { |
| FunctionWithArgs holder = (FunctionWithArgs) arg; |
| if(holder.getArgs() == null || holder.getArgs().isEmpty()) { |
| result.add(new PropertyAccess(holder.getFunction())); |
| } else { |
| throw new IllegalStateException("Expected empty FunctionWithArgs - arguments present!"); |
| } |
| } else { |
| result.add(new PropertyAccess(arg)); |
| } |
| } else { |
| result.add(new FunctionWithArgs(fn, args)); |
| } |
| |
| index++; |
| do { |
| skipWhitespace(); |
| if (index >= expression.length()) |
| return result; |
| char c = expression.charAt(index); |
| if (c == '.') { |
| // chained expression |
| int chainStart = index; |
| index++; |
| Object next = next(); |
| if (next instanceof List) { |
| result.addAll((Collection<?>) next); |
| } else if (next instanceof PropertyAccess) { |
| result.add(next); |
| } else { |
| throw new IllegalStateException("Expected functions following position " + chainStart); |
| } |
| } else if (c == '[') { |
| int selectorsStart = index; |
| Object next = next(); |
| if (next instanceof List) { |
| result.addAll((Collection<? extends PropertyAccess>) next); |
| skipWhitespace(); |
| if (index >= expression.length()) |
| return result; |
| } else { |
| throw new IllegalStateException("Expected property selectors following position " + selectorsStart); |
| } |
| } else { |
| // following word not something handled at this level; assume parent will handle (or throw) - e.g. a , or extra ) |
| return result; |
| } |
| } while (true); |
| } else { |
| // previously we returned a null-arg function; now we treat as explicit property access, |
| // and places that need it as a function with arguments from a map key convert it on to new FunctionWithArgs(selector, null) |
| return new PropertyAccess(fn); |
| } |
| } |
| |
| private void skipWhitespace() { |
| while (index<expression.length() && Character.isWhitespace(expression.charAt(index))) |
| index++; |
| } |
| |
| } |