Java tutorial
package org.jolokia.converter.object; /* * Copyright 2009-2011 Roland Huss * * 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. */ import java.util.*; import javax.management.openmbean.*; import org.json.simple.*; /** * Converter for {@link TabularData} * * @author roland * @since 28.09.11 */ class TabularDataConverter extends OpenTypeConverter<TabularType> { // Fixed key names for tabular data represention maps for MXBeans. private static final String TD_KEY_KEY = "key"; private static final String TD_KEY_VALUE = "value"; /** * Constructor * * @param pDispatcher parent converter used for recursive conversion */ public TabularDataConverter(OpenTypeConverter pDispatcher) { super(pDispatcher); } /** {@inheritDoc} */ @Override boolean canConvert(OpenType pType) { return pType instanceof TabularType; } /** {@inheritDoc} */ @Override Object convertToObject(TabularType pType, Object pFrom) { JSONObject value = getAsJsonObject(pFrom); // Convert simple map representation (with rowtype "key" and "value") if (checkForMapAttributeWithSimpleKey(pType)) { return convertToTabularTypeFromMap(pType, value); } // If it is given a a full representation (with "indexNames" and "values"), then parse this // accordingly if (checkForFullTabularDataRepresentation(value, pType)) { return convertTabularDataFromFullRepresentation(value, pType); } // Its a plain TabularData, which is tried to convert rom a maps of maps TabularDataSupport tabularData = new TabularDataSupport(pType); // Recursively go down the map and collect the values putRowsToTabularData(tabularData, value, pType.getIndexNames().size()); return tabularData; } // ========================================================================================================= private JSONObject getAsJsonObject(Object pFrom) { JSONAware jsonVal = toJSON(pFrom); if (!(jsonVal instanceof JSONObject)) { throw new IllegalArgumentException( "Expected JSON type for a TabularData is JSONObject, not " + jsonVal.getClass()); } return (JSONObject) jsonVal; } private boolean checkForMapAttributeWithSimpleKey(TabularType pType) { // The key and value must have a specific format return checkForMapKey(pType) && checkForMapValue(pType); } // A map is translated into a TabularData with a rowtype with two entries: "value" and "key" private boolean checkForMapValue(TabularType pType) { CompositeType rowType = pType.getRowType(); // Two entries in the row: "key" and "value" return rowType.containsKey(TD_KEY_VALUE) && rowType.containsKey(TD_KEY_KEY) && rowType.keySet().size() == 2; } // The tabular data representing a map must have a single index named "key" which must be a simple type private boolean checkForMapKey(TabularType pType) { List<String> indexNames = pType.getIndexNames(); return // Single index named "key" indexNames.size() == 1 && indexNames.contains(TD_KEY_KEY) && // Only convert to map for simple types for all others use normal conversion. See #105 for details. pType.getRowType().getType(TD_KEY_KEY) instanceof SimpleType; } // Check for a full table data representation and do some sanity checks private boolean checkForFullTabularDataRepresentation(JSONObject pValue, TabularType pType) { if (pValue.containsKey("indexNames") && pValue.containsKey("values") && pValue.size() == 2) { Object jsonVal = pValue.get("indexNames"); if (!(jsonVal instanceof JSONArray)) { throw new IllegalArgumentException( "Index names for tabular data must given as JSON array, not " + jsonVal.getClass()); } JSONArray indexNames = (JSONArray) jsonVal; List<String> tabularIndexNames = pType.getIndexNames(); if (indexNames.size() != tabularIndexNames.size()) { throw new IllegalArgumentException( "Given array with index names must have " + tabularIndexNames.size() + " entries " + "(given: " + indexNames + ", required: " + tabularIndexNames + ")"); } for (Object index : indexNames) { if (!tabularIndexNames.contains(index.toString())) { throw new IllegalArgumentException("No index with name '" + index + "' known " + "(given: " + indexNames + ", required: " + tabularIndexNames + ")"); } } return true; } return false; } private TabularData convertToTabularTypeFromMap(TabularType pType, JSONObject pValue) { CompositeType rowType = pType.getRowType(); // A TabularData is requested for mapping a map for the call to an MXBean // as described in http://download.oracle.com/javase/6/docs/api/javax/management/MXBean.html // This means, we will convert a JSONObject to the required format TabularDataSupport tabularData = new TabularDataSupport(pType); @SuppressWarnings("unchecked") Map<String, String> jsonObj = (Map<String, String>) pValue; for (Map.Entry<String, String> entry : jsonObj.entrySet()) { Map<String, Object> map = new HashMap<String, Object>(); map.put("key", getDispatcher().convertToObject(rowType.getType("key"), entry.getKey())); map.put("value", getDispatcher().convertToObject(rowType.getType("value"), entry.getValue())); try { CompositeData compositeData = new CompositeDataSupport(rowType, map); tabularData.put(compositeData); } catch (OpenDataException e) { throw new IllegalArgumentException(e.getMessage(), e); } } return tabularData; } // Convert complex representation containing "indexNames" and "values" private TabularData convertTabularDataFromFullRepresentation(JSONObject pValue, TabularType pType) { JSONAware jsonVal; jsonVal = (JSONAware) pValue.get("values"); if (!(jsonVal instanceof JSONArray)) { throw new IllegalArgumentException("Values for tabular data of type " + pType + " must given as JSON array, not " + jsonVal.getClass()); } TabularDataSupport tabularData = new TabularDataSupport(pType); for (Object val : (JSONArray) jsonVal) { if (!(val instanceof JSONObject)) { throw new IllegalArgumentException( "Tabular-Data values must be given as JSON objects, not " + val.getClass()); } tabularData.put((CompositeData) getDispatcher().convertToObject(pType.getRowType(), val)); } return tabularData; } private void putRowsToTabularData(TabularDataSupport pTabularData, JSONObject pValue, int pLevel) { TabularType type = pTabularData.getTabularType(); for (Object value : pValue.values()) { if (!(value instanceof JSONObject)) { throw new IllegalArgumentException( "Cannot convert " + pValue + " to type " + type + " because the object values provided (" + value.getClass() + ") is not of the expected type JSONObject at level " + pLevel); } JSONObject jsonValue = (JSONObject) value; if (pLevel > 1) { putRowsToTabularData(pTabularData, jsonValue, pLevel - 1); } else { pTabularData.put((CompositeData) getDispatcher().convertToObject(type.getRowType(), jsonValue)); } } } }