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/*
* Copyright (C) 2015 The Android Open Source Project
*
* 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://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 com.android.statementservice.retriever;
import android.util.JsonReader;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;
/**
* Utility class that parses JSON-formatted statements.
*/
/* package private */ final class StatementParser {
private static final String FIELD_NOT_STRING_FORMAT_STRING = "Expected %s to be string.";
private static final String FIELD_NOT_ARRAY_FORMAT_STRING = "Expected %s to be array.";
/**
* Parses a JSON array of statements.
*/
static ParsedStatement parseStatementList(String statementList, AbstractAsset source)
throws JSONException, IOException {
List<Statement> statements = new ArrayList<Statement>();
List<String> delegates = new ArrayList<String>();
JsonReader reader = new JsonReader(new StringReader(statementList));
reader.setLenient(false);
reader.beginArray();
while (reader.hasNext()) {
ParsedStatement result;
try {
result = parseStatement(reader, source);
} catch (AssociationServiceException e) {
// The element in the array is well formatted Json but not a well-formed Statement.
continue;
}
statements.addAll(result.getStatements());
delegates.addAll(result.getDelegates());
}
reader.endArray();
return new ParsedStatement(statements, delegates);
}
/**
* Parses a single JSON statement.
*/
static ParsedStatement parseStatement(String statementString, AbstractAsset source)
throws AssociationServiceException, IOException, JSONException {
JsonReader reader = new JsonReader(new StringReader(statementString));
reader.setLenient(false);
return parseStatement(reader, source);
}
/**
* Parses a single JSON statement. This method guarantees that exactly one JSON object
* will be consumed.
*/
static ParsedStatement parseStatement(JsonReader reader, AbstractAsset source)
throws JSONException, AssociationServiceException, IOException {
List<Statement> statements = new ArrayList<Statement>();
List<String> delegates = new ArrayList<String>();
JSONObject statement = JsonParser.parse(reader);
if (statement.optString(Utils.DELEGATE_FIELD_DELEGATE, null) != null) {
delegates.add(statement.optString(Utils.DELEGATE_FIELD_DELEGATE));
} else {
JSONObject targetObject = statement.optJSONObject(Utils.ASSET_DESCRIPTOR_FIELD_TARGET);
if (targetObject == null) {
throw new AssociationServiceException(String.format(
FIELD_NOT_STRING_FORMAT_STRING, Utils.ASSET_DESCRIPTOR_FIELD_TARGET));
}
JSONArray relations = statement.optJSONArray(Utils.ASSET_DESCRIPTOR_FIELD_RELATION);
if (relations == null) {
throw new AssociationServiceException(String.format(
FIELD_NOT_ARRAY_FORMAT_STRING, Utils.ASSET_DESCRIPTOR_FIELD_RELATION));
}
AbstractAsset target = AssetFactory.create(targetObject);
for (int i = 0; i < relations.length(); i++) {
statements.add(Statement
.create(source, target, Relation.create(relations.getString(i))));
}
}
return new ParsedStatement(statements, delegates);
}
}
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