112 lines
3.8 KiB
Java
112 lines
3.8 KiB
Java
/*
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* Copyright (C) 2008 Google Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.mcteam.factions.gson;
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import java.io.IOException;
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import java.util.Map;
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/**
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* A navigator to navigate a tree of JsonElement nodes in Depth-first order
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*
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* @author Inderjeet Singh
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*/
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final class JsonTreeNavigator {
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private final JsonElementVisitor visitor;
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private final boolean visitNulls;
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JsonTreeNavigator(JsonElementVisitor visitor, boolean visitNulls) {
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this.visitor = visitor;
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this.visitNulls = visitNulls;
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}
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public void navigate(JsonElement element) throws IOException {
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if (element.isJsonNull()) {
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visitor.visitNull();
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} else if (element.isJsonArray()) {
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JsonArray array = element.getAsJsonArray();
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visitor.startArray(array);
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boolean isFirst = true;
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for (JsonElement child : array) {
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visitChild(array, child, isFirst);
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if (isFirst) {
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isFirst = false;
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}
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}
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visitor.endArray(array);
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} else if (element.isJsonObject()) {
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JsonObject object = element.getAsJsonObject();
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visitor.startObject(object);
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boolean isFirst = true;
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for (Map.Entry<String, JsonElement> member : object.entrySet()) {
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boolean visited = visitChild(object, member.getKey(), member.getValue(), isFirst);
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if (visited && isFirst) {
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isFirst = false;
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}
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}
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visitor.endObject(object);
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} else { // must be JsonPrimitive
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visitor.visitPrimitive(element.getAsJsonPrimitive());
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}
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}
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/**
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* Returns true if the child was visited, false if it was skipped.
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*/
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private boolean visitChild(JsonObject parent, String childName, JsonElement child,
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boolean isFirst) throws IOException {
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if (child.isJsonNull()) {
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if (visitNulls) {
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visitor.visitNullObjectMember(parent, childName, isFirst);
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navigate(child.getAsJsonNull());
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} else { // Null value is being skipped.
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return false;
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}
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} else if (child.isJsonArray()) {
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JsonArray childAsArray = child.getAsJsonArray();
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visitor.visitObjectMember(parent, childName, childAsArray, isFirst);
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navigate(childAsArray);
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} else if (child.isJsonObject()) {
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JsonObject childAsObject = child.getAsJsonObject();
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visitor.visitObjectMember(parent, childName, childAsObject, isFirst);
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navigate(childAsObject);
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} else { // is a JsonPrimitive
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visitor.visitObjectMember(parent, childName, child.getAsJsonPrimitive(), isFirst);
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}
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return true;
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}
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/**
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* Returns true if the child was visited, false if it was skipped.
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*/
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private void visitChild(JsonArray parent, JsonElement child, boolean isFirst) throws IOException {
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if (child.isJsonNull()) {
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visitor.visitNullArrayMember(parent, isFirst);
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navigate(child);
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} else if (child.isJsonArray()) {
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JsonArray childAsArray = child.getAsJsonArray();
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visitor.visitArrayMember(parent, childAsArray, isFirst);
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navigate(childAsArray);
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} else if (child.isJsonObject()) {
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JsonObject childAsObject = child.getAsJsonObject();
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visitor.visitArrayMember(parent, childAsObject, isFirst);
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navigate(childAsObject);
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} else { // is a JsonPrimitive
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visitor.visitArrayMember(parent, child.getAsJsonPrimitive(), isFirst);
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}
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}
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}
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