Java tutorial
/* * jabsorb - a Java to JavaScript Advanced Object Request Broker * http://www.jabsorb.org * * Copyright 2007-2008 The jabsorb team * * based on original code from * JSON-RPC-Java - a JSON-RPC to Java Bridge with dynamic invocation * * Copyright Metaparadigm Pte. Ltd. 2004. * Michael Clark <michael@metaparadigm.com> * * 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 org.jabsorb.ng.serializer.impl; import java.util.AbstractList; import java.util.ArrayList; import java.util.LinkedList; import java.util.List; import java.util.Vector; import org.jabsorb.ng.JSONSerializer; import org.jabsorb.ng.serializer.AbstractSerializer; import org.jabsorb.ng.serializer.MarshallException; import org.jabsorb.ng.serializer.ObjectMatch; import org.jabsorb.ng.serializer.SerializerState; import org.jabsorb.ng.serializer.UnmarshallException; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; /** * Serializes lists * * TODO: if this serializes a superclass does it need to also specify the * subclasses? */ public class ListSerializer extends AbstractSerializer { /** * Classes that this can serialize to. */ private static final Class<?>[] _JSONClasses = new Class<?>[] { JSONObject.class }; /** * Classes that this can serialize. */ private static final Class<?>[] _serializableClasses = new Class<?>[] { List.class, ArrayList.class, LinkedList.class, Vector.class }; /** * Unique serialization id. */ private static final long serialVersionUID = 2; @Override public boolean canSerialize(final Class<?> clazz, final Class<?> jsonClazz) { return (super.canSerialize(clazz, jsonClazz) || ((jsonClazz == null || jsonClazz == JSONObject.class) && List.class.isAssignableFrom(clazz))); } @Override public Class<?>[] getJSONClasses() { return _JSONClasses; } @Override public Class<?>[] getSerializableClasses() { return _serializableClasses; } @Override public Object marshall(final SerializerState state, final Object p, final Object o) throws MarshallException { final List<?> list = (List<?>) o; final JSONObject obj = new JSONObject(); final JSONArray arr = new JSONArray(); // TODO: this same block is done everywhere. // Have a single function to do it. if (ser.getMarshallClassHints()) { try { obj.put("javaClass", o.getClass().getName()); } catch (final JSONException e) { throw new MarshallException("javaClass not found!", e); } } try { obj.put("list", arr); state.push(o, arr, "list"); } catch (final JSONException e) { throw new MarshallException("Error setting list: " + e, e); } int index = 0; try { for (final Object item : list) { // Convert the item final Object json = ser.marshall(state, arr, item, index); // Check for circular references if (JSONSerializer.CIRC_REF_OR_DUPLICATE != json) { arr.put(json); } else { // put a slot where the object would go, so it can be fixed // up properly in the fix up phase arr.put(JSONObject.NULL); } index++; } } catch (final MarshallException e) { throw new MarshallException("element " + index, e); } finally { state.pop(); } return obj; } // TODO: try unMarshall and unMarshall share 90% code. Put in into an // intermediate function. // TODO: Also cache the result somehow so that an unmarshall // following a tryUnmarshall doesn't do the same work twice! @Override public ObjectMatch tryUnmarshall(final SerializerState state, final Class<?> clazz, final Object o) throws UnmarshallException { final JSONObject jso = (JSONObject) o; String java_class; // Hint presence try { java_class = jso.getString("javaClass"); } catch (final JSONException e) { throw new UnmarshallException("Could not read javaClass", e); } if (java_class == null) { throw new UnmarshallException("no type hint"); } // Class compatibility check if (!classNameCheck(java_class)) { throw new UnmarshallException("not a List"); } // JSON Format check JSONArray jsonlist; try { jsonlist = jso.getJSONArray("list"); } catch (final JSONException e) { throw new UnmarshallException("Could not read list: " + e.getMessage(), e); } if (jsonlist == null) { throw new UnmarshallException("list missing"); } // Content check final ObjectMatch m = new ObjectMatch(-1); state.setSerialized(o, m); int idx = 0; try { for (idx = 0; idx < jsonlist.length(); idx++) { m.setMismatch(ser.tryUnmarshall(state, null, jsonlist.get(idx)).max(m).getMismatch()); } } catch (final UnmarshallException e) { throw new UnmarshallException("element " + idx + " " + e.getMessage(), e); } catch (final JSONException e) { throw new UnmarshallException("element " + idx + " " + e.getMessage(), e); } return m; } @Override public Object unmarshall(final SerializerState state, final Class<?> clazz, final Object o) throws UnmarshallException { final JSONObject jso = (JSONObject) o; String java_class; // Hint check try { java_class = jso.getString("javaClass"); } catch (final JSONException e) { throw new UnmarshallException("Could not read javaClass", e); } if (java_class == null) { throw new UnmarshallException("no type hint"); } // Create the list final AbstractList<Object> ablist; if (java_class.equals("java.util.List") || java_class.equals("java.util.AbstractList") || java_class.equals("java.util.ArrayList")) { ablist = new ArrayList<Object>(); } else if (java_class.equals("java.util.LinkedList")) { ablist = new LinkedList<Object>(); } else if (java_class.equals("java.util.Vector")) { ablist = new Vector<Object>(); } else { throw new UnmarshallException("not a List"); } // Parse the JSON list JSONArray jsonlist; try { jsonlist = jso.getJSONArray("list"); } catch (final JSONException e) { throw new UnmarshallException("Could not read list: " + e.getMessage(), e); } if (jsonlist == null) { throw new UnmarshallException("list missing"); } state.setSerialized(o, ablist); int idx = 0; try { for (idx = 0; idx < jsonlist.length(); idx++) { ablist.add(ser.unmarshall(state, null, jsonlist.get(idx))); } } catch (final UnmarshallException e) { throw new UnmarshallException("element " + idx + " " + e.getMessage(), e); } catch (final JSONException e) { throw new UnmarshallException("element " + idx + " " + e.getMessage(), e); } return ablist; } }