Java tutorial
/* * Copyright 2015-2015 Amazon Technologies, 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://aws.amazon.com/apache2.0 * * This file 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.amazonaws.services.dynamodbv2.xspec; import java.util.ArrayList; import java.util.List; import java.util.regex.Pattern; import org.apache.http.annotation.Immutable; /** * Internal representation of a path to an attribute. */ @Immutable final class Path extends UnitOfExpression { private final List<PathElement> elements; Path(String path) { this.elements = parse(path); } private List<PathElement> parse(String path) { if (path == null) { throw new NullPointerException("path"); } final String[] split = path.split(Pattern.quote(".")); final List<PathElement> elements = new ArrayList<PathElement>(); for (String element : split) { int index = element.indexOf('['); if (index == -1) { elements.add(new NamedElement(element)); continue; } if (index == 0) { throw new IllegalArgumentException("Bogus path: " + path); } elements.add(new NamedElement(element.substring(0, index))); do { element = element.substring(index + 1); index = element.indexOf(']'); if (index == -1) { throw new IllegalArgumentException("Bogus path: " + path); } int arrayIndex = Integer.parseInt(element.substring(0, index)); elements.add(new ArrayIndexElement(arrayIndex)); element = element.substring(index + 1); index = element.indexOf('['); if (index > 0) throw new IllegalArgumentException("Bogus path: " + path); } while (index != -1); if (!element.isEmpty()) { throw new IllegalArgumentException("Bogus path: " + path); } } return elements; } @Override String asSubstituted(SubstitutionContext context) { StringBuffer sb = new StringBuffer(); for (PathElement e : elements) { if (sb.length() == 0) sb.append(e.asToken(context)); else { sb.append(e.asNestedToken(context)); } } return sb.toString(); } // Reverse to the original input path for debug purposes. @Override public String toString() { StringBuffer sb = new StringBuffer(); for (PathElement e : elements) { if (sb.length() == 0) sb.append(e.toString()); else { sb.append(e.asNestedPath()); } } return sb.toString(); } List<PathElement> getElements() { return elements; } }