serval-dna/java/org/servalproject/json/JSONTableScanner.java
2016-07-25 16:54:11 +09:30

118 lines
3.9 KiB
Java

/**
* Copyright (C) 2014 Serval Project Inc.
*
* This file is part of Serval Software (http://www.servalproject.org)
*
* Serval Software is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This source code is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this source code; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.servalproject.json;
import java.lang.reflect.InvocationTargetException;
import java.io.IOException;
import java.util.Vector;
import java.util.Map;
import java.util.HashMap;
import java.util.HashSet;
public class JSONTableScanner {
private static class Column {
public boolean supported;
public String label;
public Class type;
public JSONTokeniser.Narrow opts;
}
HashMap<String,Column> columnMap;
Column[] columns;
public JSONTableScanner()
{
columnMap = new HashMap<String,Column>();
}
public JSONTableScanner addColumn(String label, Class type)
{
return addColumn(label, type, JSONTokeniser.Narrow.NO_NULL);
}
public JSONTableScanner addColumn(String label, Class type, JSONTokeniser.Narrow opts)
{
assert !columnMap.containsKey(label);
Column col = new Column();
col.label = label;
col.type = type;
col.opts = opts;
col.supported = JSONTokeniser.supportsNarrowTo(col.type);
columnMap.put(label, col);
return this;
}
public void consumeHeaderArray(JSONTokeniser json) throws IOException, JSONInputException
{
Vector<String> headers = new Vector<String>();
json.consumeArray(headers, String.class);
if (headers.size() < 1)
throw new JSONInputException("malformed JSON table, empty headers array");
columns = new Column[headers.size()];
HashSet<String> headerSet = new HashSet<String>(columnMap.size());
for (int i = 0; i < headers.size(); ++i) {
String header = headers.get(i);
if (columnMap.containsKey(header)) {
if (headerSet.contains(header))
throw new JSONInputException("malformed JSON table, duplicate column header: \"" + header + "\"");
headerSet.add(header);
columns[i] = columnMap.get(header);
}
}
for (String header: columnMap.keySet())
if (!headerSet.contains(header))
throw new JSONInputException("malformed JSON table, missing column header: \"" + header + "\"");
}
@SuppressWarnings("unchecked")
public Map<String,Object> consumeRowArray(JSONTokeniser json) throws IOException, JSONInputException
{
Object[] row = new Object[columns.length];
json.consumeArray(row, JSONTokeniser.Narrow.ALLOW_NULL);
HashMap<String,Object> rowMap = new HashMap<String,Object>(row.length);
for (int i = 0; i < row.length; ++i) {
Column col = columns[i];
Object value = null;
if (col != null) {
try {
if (col.supported)
value = JSONTokeniser.narrow(row[i], col.type, col.opts);
else {
value = JSONTokeniser.narrow(row[i], col.opts);
if (value != null)
value = col.type.getConstructor(value.getClass()).newInstance(value);
}
rowMap.put(col.label, value);
} catch (JSONInputException e){
throw new JSONInputException("invalid column value: " + col.label + "; " + e.getMessage(), e);
} catch (InvocationTargetException e) {
throw new JSONInputException("invalid column value: " + col.label + "=\"" + value + "\"", e.getTargetException());
} catch (Exception e) {
throw new JSONInputException("invalid column value: " + col.label + "=\"" + value + "\"", e);
}
}
}
return rowMap;
}
}