/**
* Copyright 2011-2014 Asakusa Framework Team.
*
* 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.asakusafw.testdriver.json;
import java.io.EOFException;
import java.io.IOException;
import java.io.Reader;
import java.net.URI;
import java.text.MessageFormat;
import com.asakusafw.testdriver.core.DataModelDefinition;
import com.asakusafw.testdriver.core.DataModelReflection;
import com.asakusafw.testdriver.core.DataModelSource;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonStreamParser;
/**
* {@link DataModelSource} from JSON object stream.
* @since 0.2.0
* @version 0.6.0
*/
public class JsonDataModelSource implements DataModelSource {
private final DataModelDefinition<?> definition;
private final URI id;
private final Reader reader;
private final JsonStreamParser parser;
private boolean first = true;
/**
* Creates a new instance.
* @param id source ID (nullable)
* @param definition the data model definition
* @param reader source character stream
* @throws IllegalArgumentException if some parameters were {@code null}
*/
public JsonDataModelSource(URI id, DataModelDefinition<?> definition, Reader reader) {
if (definition == null) {
throw new IllegalArgumentException("definition must not be null"); //$NON-NLS-1$
}
if (reader == null) {
throw new IllegalArgumentException("reader must not be null"); //$NON-NLS-1$
}
this.id = id;
this.definition = definition;
this.reader = reader;
this.parser = new JsonStreamParser(reader);
}
@Override
public DataModelReflection next() throws IOException {
if (first) {
try {
parser.hasNext();
} catch (JsonParseException e) {
if (e.getCause() instanceof EOFException) {
return null;
}
}
first = false;
}
try {
if (parser.hasNext() == false) {
return null;
}
JsonElement element = parser.next();
return JsonObjectDriver.convert(definition, element);
} catch (JsonParseException e) {
throw new IOException(MessageFormat.format(
"Malformed JSON object (id={0})",
id), e);
}
}
@Override
public void close() throws IOException {
reader.close();
}
}