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/**
 * Copyright 2010-present Facebook.
 *
 * 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.facebook.model;

import com.facebook.FacebookGraphObjectException;
import com.facebook.internal.Utility;
import com.facebook.internal.Validate;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.lang.reflect.*;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;

/**
 * GraphObject is the primary interface used by the Facebook SDK for Android to represent objects in the Facebook
 * Social Graph and the Facebook Open Graph (OG). It is the base interface for all typed access to graph objects
 * in the SDK. No concrete classes implement GraphObject or its derived interfaces. Rather, they are implemented as
 * proxies (see the {@link com.facebook.model.GraphObject.Factory Factory} class) that provide strongly-typed property
 * getters and setters to access the underlying data. Since the primary use case for graph objects is sending and
 * receiving them over the wire to/from Facebook services, they are represented as JSONObjects. No validation is done
 * that a graph object is actually of a specific type -- any graph object can be treated as any GraphObject-derived
 * interface, and the presence or absence of specific properties determines its suitability for use as that
 * particular type of object.
 * 
*/ public interface GraphObject { /** * Returns a new proxy that treats this graph object as a different GraphObject-derived type. * @param graphObjectClass the type of GraphObject to return * @return a new instance of the GraphObject-derived-type that references the same underlying data */ T cast(Class graphObjectClass); /** * Returns a Java Collections map of names and properties. Modifying the returned map modifies the * inner JSON representation. * @return a Java Collections map representing the GraphObject state */ Map asMap(); /** * Gets the underlying JSONObject representation of this graph object. * @return the underlying JSONObject representation of this graph object */ JSONObject getInnerJSONObject(); /** * Gets a property of the GraphObject * @param propertyName the name of the property to get * @return the value of the named property */ Object getProperty(String propertyName); /** * Gets a property of the GraphObject, cast to a particular GraphObject-derived interface. This gives some of * the benefits of having a property getter defined to return a GraphObject-derived type without requiring * explicit definition of an interface to define the getter. * @param propertyName the name of the property to get * @param graphObjectClass the GraphObject-derived interface to cast the property to * @return */ T getPropertyAs(String propertyName, Class graphObjectClass); /** * Gets a property of the GraphObject, cast to a a list of instances of a particular GraphObject-derived interface. * This gives some of the benefits of having a property getter defined to return a GraphObject-derived type without * requiring explicit definition of an interface to define the getter. * @param propertyName the name of the property to get * @param graphObjectClass the GraphObject-derived interface to cast the property to a list of * @return */ GraphObjectList getPropertyAsList(String propertyName, Class graphObjectClass); /** * Sets a property of the GraphObject * @param propertyName the name of the property to set * @param propertyValue the value of the named property to set */ void setProperty(String propertyName, Object propertyValue); /** * Removes a property of the GraphObject * @param propertyName the name of the property to remove */ void removeProperty(String propertyName); /** * Creates proxies that implement GraphObject, GraphObjectList, and their derived types. These proxies allow access * to underlying collections and name/value property bags via strongly-typed property getters and setters. *

* This supports get/set properties that use primitive types, JSON types, Date, other GraphObject types, Iterable, * Collection, List, and GraphObjectList. */ final class Factory { private static final HashSet> verifiedGraphObjectClasses = new HashSet>(); private static final SimpleDateFormat[] dateFormats = new SimpleDateFormat[] { new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.US), new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss", Locale.US), new SimpleDateFormat("yyyy-MM-dd", Locale.US), }; // No objects of this type should exist. private Factory() { } /** * Creates a GraphObject proxy that provides typed access to the data in an underlying JSONObject. * @param json the JSONObject containing the data to be exposed * @return a GraphObject that represents the underlying data * * @throws com.facebook.FacebookException * If the passed in Class is not a valid GraphObject interface */ public static GraphObject create(JSONObject json) { return create(json, GraphObject.class); } /** * Creates a GraphObject-derived proxy that provides typed access to the data in an underlying JSONObject. * @param json the JSONObject containing the data to be exposed * @param graphObjectClass the GraphObject-derived type to return * @return a graphObjectClass that represents the underlying data * * @throws com.facebook.FacebookException * If the passed in Class is not a valid GraphObject interface */ public static T create(JSONObject json, Class graphObjectClass) { return createGraphObjectProxy(graphObjectClass, json); } /** * Creates a GraphObject proxy that initially contains no data. * @return a GraphObject with no data * * @throws com.facebook.FacebookException * If the passed in Class is not a valid GraphObject interface */ public static GraphObject create() { return create(GraphObject.class); } /** * Creates a GraphObject-derived proxy that initially contains no data. * @param graphObjectClass the GraphObject-derived type to return * @return a graphObjectClass with no data * * @throws com.facebook.FacebookException * If the passed in Class is not a valid GraphObject interface */ public static T create(Class graphObjectClass) { return createGraphObjectProxy(graphObjectClass, new JSONObject()); } /** * Determines if two GraphObjects represent the same underlying graph object, based on their IDs. * @param a a graph object * @param b another graph object * @return true if both graph objects have an ID and it is the same ID, false otherwise */ public static boolean hasSameId(GraphObject a, GraphObject b) { if (a == null || b == null || !a.asMap().containsKey("id") || !b.asMap().containsKey("id")) { return false; } if (a.equals(b)) { return true; } Object idA = a.getProperty("id"); Object idB = b.getProperty("id"); if (idA == null || idB == null || !(idA instanceof String) || !(idB instanceof String)) { return false; } return idA.equals(idB); } /** * Creates a GraphObjectList-derived proxy that provides typed access to the data in an underlying JSONArray. * @param array the JSONArray containing the data to be exposed * @param graphObjectClass the GraphObject-derived type to return * @return a graphObjectClass that represents the underlying data * * @throws com.facebook.FacebookException * If the passed in Class is not a valid GraphObject interface */ public static GraphObjectList createList(JSONArray array, Class graphObjectClass) { return new GraphObjectListImpl(array, graphObjectClass); } /** * Creates a GraphObjectList-derived proxy that initially contains no data. * @param graphObjectClass the GraphObject-derived type to return * @return a GraphObjectList with no data * * @throws com.facebook.FacebookException * If the passed in Class is not a valid GraphObject interface */ public static GraphObjectList createList(Class graphObjectClass) { return createList(new JSONArray(), graphObjectClass); } private static T createGraphObjectProxy(Class graphObjectClass, JSONObject state) { verifyCanProxyClass(graphObjectClass); Class[] interfaces = new Class[] { graphObjectClass }; GraphObjectProxy graphObjectProxy = new GraphObjectProxy(state, graphObjectClass); @SuppressWarnings("unchecked") T graphObject = (T) Proxy.newProxyInstance(GraphObject.class.getClassLoader(), interfaces, graphObjectProxy); return graphObject; } private static Map createGraphObjectProxyForMap(JSONObject state) { Class[] interfaces = new Class[]{Map.class}; GraphObjectProxy graphObjectProxy = new GraphObjectProxy(state, Map.class); @SuppressWarnings("unchecked") Map graphObject = (Map) Proxy .newProxyInstance(GraphObject.class.getClassLoader(), interfaces, graphObjectProxy); return graphObject; } private static synchronized boolean hasClassBeenVerified(Class graphObjectClass) { return verifiedGraphObjectClasses.contains(graphObjectClass); } private static synchronized void recordClassHasBeenVerified(Class graphObjectClass) { verifiedGraphObjectClasses.add(graphObjectClass); } private static void verifyCanProxyClass(Class graphObjectClass) { if (hasClassBeenVerified(graphObjectClass)) { return; } if (!graphObjectClass.isInterface()) { throw new FacebookGraphObjectException("Factory can only wrap interfaces, not class: " + graphObjectClass.getName()); } Method[] methods = graphObjectClass.getMethods(); for (Method method : methods) { String methodName = method.getName(); int parameterCount = method.getParameterTypes().length; Class returnType = method.getReturnType(); boolean hasPropertyNameOverride = method.isAnnotationPresent(PropertyName.class); if (method.getDeclaringClass().isAssignableFrom(GraphObject.class)) { // Don't worry about any methods from GraphObject or one of its base classes. continue; } else if (parameterCount == 1 && returnType == Void.TYPE) { if (hasPropertyNameOverride) { // If a property override is present, it MUST be valid. We don't fallback // to using the method name if (!Utility.isNullOrEmpty(method.getAnnotation(PropertyName.class).value())) { continue; } } else if (methodName.startsWith("set") && methodName.length() > 3) { // Looks like a valid setter continue; } } else if (parameterCount == 0 && returnType != Void.TYPE) { if (hasPropertyNameOverride) { // If a property override is present, it MUST be valid. We don't fallback // to using the method name if (!Utility.isNullOrEmpty(method.getAnnotation(PropertyName.class).value())) { continue; } } else if (methodName.startsWith("get") && methodName.length() > 3) { // Looks like a valid getter continue; } } throw new FacebookGraphObjectException("Factory can't proxy method: " + method.toString()); } recordClassHasBeenVerified(graphObjectClass); } // If expectedType is a generic type, expectedTypeAsParameterizedType must be provided in order to determine // generic parameter types. static U coerceValueToExpectedType(Object value, Class expectedType, ParameterizedType expectedTypeAsParameterizedType) { if (value == null) { if (boolean.class.equals(expectedType)) { @SuppressWarnings("unchecked") U result = (U) (Boolean) false; return result; } else if (char.class.equals(expectedType)) { @SuppressWarnings("unchecked") U result = (U) (Character) '\0'; return result; } else if (expectedType.isPrimitive()) { @SuppressWarnings("unchecked") U result = (U) (Number) 0; return result; } else { return null; } } Class valueType = value.getClass(); if (expectedType.isAssignableFrom(valueType)) { @SuppressWarnings("unchecked") U result = (U) value; return result; } if (expectedType.isPrimitive()) { // If the result is a primitive, let the runtime succeed or fail at unboxing it. @SuppressWarnings("unchecked") U result = (U) value; return result; } if (GraphObject.class.isAssignableFrom(expectedType)) { @SuppressWarnings("unchecked") Class graphObjectClass = (Class) expectedType; // We need a GraphObject, but we don't have one. if (JSONObject.class.isAssignableFrom(valueType)) { // We can wrap a JSONObject as a GraphObject. @SuppressWarnings("unchecked") U result = (U) createGraphObjectProxy(graphObjectClass, (JSONObject) value); return result; } else if (GraphObject.class.isAssignableFrom(valueType)) { // We can cast a GraphObject-derived class to another GraphObject-derived class. @SuppressWarnings("unchecked") U result = (U) ((GraphObject) value).cast(graphObjectClass); return result; } else { throw new FacebookGraphObjectException("Can't create GraphObject from " + valueType.getName()); } } else if (Iterable.class.equals(expectedType) || Collection.class.equals(expectedType) || List.class.equals(expectedType) || GraphObjectList.class.equals(expectedType)) { if (expectedTypeAsParameterizedType == null) { throw new FacebookGraphObjectException("can't infer generic type of: " + expectedType.toString()); } Type[] actualTypeArguments = expectedTypeAsParameterizedType.getActualTypeArguments(); if (actualTypeArguments == null || actualTypeArguments.length != 1 || !(actualTypeArguments[0] instanceof Class)) { throw new FacebookGraphObjectException( "Expect collection properties to be of a type with exactly one generic parameter."); } Class collectionGenericArgument = (Class) actualTypeArguments[0]; if (JSONArray.class.isAssignableFrom(valueType)) { JSONArray jsonArray = (JSONArray) value; @SuppressWarnings("unchecked") U result = (U) createList(jsonArray, collectionGenericArgument); return result; } else { throw new FacebookGraphObjectException("Can't create Collection from " + valueType.getName()); } } else if (String.class.equals(expectedType)) { if (Double.class.isAssignableFrom(valueType) || Float.class.isAssignableFrom(valueType)) { @SuppressWarnings("unchecked") U result = (U) String.format("%f", value); return result; } else if (Number.class.isAssignableFrom(valueType)) { @SuppressWarnings("unchecked") U result = (U) String.format("%d", value); return result; } } else if (Date.class.equals(expectedType)) { if (String.class.isAssignableFrom(valueType)) { for (SimpleDateFormat format : dateFormats) { try { Date date = format.parse((String) value); if (date != null) { @SuppressWarnings("unchecked") U result = (U) date; return result; } } catch (ParseException e) { // Keep going. } } } } throw new FacebookGraphObjectException("Can't convert type" + valueType.getName() + " to " + expectedType.getName()); } static String convertCamelCaseToLowercaseWithUnderscores(String string) { string = string.replaceAll("([a-z])([A-Z])", "$1_$2"); return string.toLowerCase(Locale.US); } private static Object getUnderlyingJSONObject(Object obj) { if (obj == null) { return null; } Class objClass = obj.getClass(); if (GraphObject.class.isAssignableFrom(objClass)) { GraphObject graphObject = (GraphObject) obj; return graphObject.getInnerJSONObject(); } else if (GraphObjectList.class.isAssignableFrom(objClass)) { GraphObjectList graphObjectList = (GraphObjectList) obj; return graphObjectList.getInnerJSONArray(); } else if (Iterable.class.isAssignableFrom(objClass)) { JSONArray jsonArray = new JSONArray(); Iterable iterable = (Iterable) obj; for (Object o : iterable ) { if (GraphObject.class.isAssignableFrom(o.getClass())) { jsonArray.put(((GraphObject)o).getInnerJSONObject()); } else { jsonArray.put(o); } } return jsonArray; } return obj; } private abstract static class ProxyBase implements InvocationHandler { // Pre-loaded Method objects for the methods in java.lang.Object private static final String EQUALS_METHOD = "equals"; private static final String TOSTRING_METHOD = "toString"; protected final STATE state; protected ProxyBase(STATE state) { this.state = state; } // Declared to return Object just to simplify implementation of proxy helpers. protected final Object throwUnexpectedMethodSignature(Method method) { throw new FacebookGraphObjectException(getClass().getName() + " got an unexpected method signature: " + method.toString()); } protected final Object proxyObjectMethods(Object proxy, Method method, Object[] args) throws Throwable { String methodName = method.getName(); if (methodName.equals(EQUALS_METHOD)) { Object other = args[0]; if (other == null) { return false; } InvocationHandler handler = Proxy.getInvocationHandler(other); if (!(handler instanceof GraphObjectProxy)) { return false; } GraphObjectProxy otherProxy = (GraphObjectProxy) handler; return this.state.equals(otherProxy.state); } else if (methodName.equals(TOSTRING_METHOD)) { return toString(); } // For others, just defer to the implementation object. return method.invoke(this.state, args); } } private final static class GraphObjectProxy extends ProxyBase { private static final String CLEAR_METHOD = "clear"; private static final String CONTAINSKEY_METHOD = "containsKey"; private static final String CONTAINSVALUE_METHOD = "containsValue"; private static final String ENTRYSET_METHOD = "entrySet"; private static final String GET_METHOD = "get"; private static final String ISEMPTY_METHOD = "isEmpty"; private static final String KEYSET_METHOD = "keySet"; private static final String PUT_METHOD = "put"; private static final String PUTALL_METHOD = "putAll"; private static final String REMOVE_METHOD = "remove"; private static final String SIZE_METHOD = "size"; private static final String VALUES_METHOD = "values"; private static final String CAST_METHOD = "cast"; private static final String CASTTOMAP_METHOD = "asMap"; private static final String GETPROPERTY_METHOD = "getProperty"; private static final String GETPROPERTYAS_METHOD = "getPropertyAs"; private static final String GETPROPERTYASLIST_METHOD = "getPropertyAsList"; private static final String SETPROPERTY_METHOD = "setProperty"; private static final String REMOVEPROPERTY_METHOD = "removeProperty"; private static final String GETINNERJSONOBJECT_METHOD = "getInnerJSONObject"; private final Class graphObjectClass; public GraphObjectProxy(JSONObject state, Class graphObjectClass) { super(state); this.graphObjectClass = graphObjectClass; } @Override public String toString() { return String.format("GraphObject{graphObjectClass=%s, state=%s}", graphObjectClass.getSimpleName(), state); } @Override public final Object invoke(Object proxy, Method method, Object[] args) throws Throwable { Class declaringClass = method.getDeclaringClass(); if (declaringClass == Object.class) { return proxyObjectMethods(proxy, method, args); } else if (declaringClass == Map.class) { return proxyMapMethods(method, args); } else if (declaringClass == GraphObject.class) { return proxyGraphObjectMethods(proxy, method, args); } else if (GraphObject.class.isAssignableFrom(declaringClass)) { return proxyGraphObjectGettersAndSetters(method, args); } return throwUnexpectedMethodSignature(method); } private final Object proxyMapMethods(Method method, Object[] args) { String methodName = method.getName(); if (methodName.equals(CLEAR_METHOD)) { JsonUtil.jsonObjectClear(this.state); return null; } else if (methodName.equals(CONTAINSKEY_METHOD)) { return this.state.has((String) args[0]); } else if (methodName.equals(CONTAINSVALUE_METHOD)) { return JsonUtil.jsonObjectContainsValue(this.state, args[0]); } else if (methodName.equals(ENTRYSET_METHOD)) { return JsonUtil.jsonObjectEntrySet(this.state); } else if (methodName.equals(GET_METHOD)) { return this.state.opt((String) args[0]); } else if (methodName.equals(ISEMPTY_METHOD)) { return this.state.length() == 0; } else if (methodName.equals(KEYSET_METHOD)) { return JsonUtil.jsonObjectKeySet(this.state); } else if (methodName.equals(PUT_METHOD)) { return setJSONProperty(args); } else if (methodName.equals(PUTALL_METHOD)) { Map map = null; if (args[0] instanceof Map) { @SuppressWarnings("unchecked") Map castMap = (Map) args[0]; map = castMap; } else if (args[0] instanceof GraphObject) { map = ((GraphObject) args[0]).asMap(); } else { return null; } JsonUtil.jsonObjectPutAll(this.state, map); return null; } else if (methodName.equals(REMOVE_METHOD)) { this.state.remove((String) args[0]); return null; } else if (methodName.equals(SIZE_METHOD)) { return this.state.length(); } else if (methodName.equals(VALUES_METHOD)) { return JsonUtil.jsonObjectValues(this.state); } return throwUnexpectedMethodSignature(method); } private final Object proxyGraphObjectMethods(Object proxy, Method method, Object[] args) { String methodName = method.getName(); if (methodName.equals(CAST_METHOD)) { @SuppressWarnings("unchecked") Class graphObjectClass = (Class) args[0]; if (graphObjectClass != null && graphObjectClass.isAssignableFrom(this.graphObjectClass)) { return proxy; } return Factory.createGraphObjectProxy(graphObjectClass, this.state); } else if (methodName.equals(GETINNERJSONOBJECT_METHOD)) { InvocationHandler handler = Proxy.getInvocationHandler(proxy); GraphObjectProxy otherProxy = (GraphObjectProxy) handler; return otherProxy.state; } else if (methodName.equals(CASTTOMAP_METHOD)) { return Factory.createGraphObjectProxyForMap(this.state); } else if (methodName.equals(GETPROPERTY_METHOD)) { return state.opt((String) args[0]); } else if (methodName.equals(GETPROPERTYAS_METHOD)) { Object value = state.opt((String) args[0]); Class expectedType = (Class) args[1]; return coerceValueToExpectedType(value, expectedType, null); } else if (methodName.equals(GETPROPERTYASLIST_METHOD)) { Object value = state.opt((String) args[0]); final Class expectedType = (Class) args[1]; ParameterizedType parameterizedType = new ParameterizedType() { @Override public Type[] getActualTypeArguments() { return new Type[]{ expectedType }; } @Override public Type getOwnerType() { return null; } @Override public Type getRawType() { return GraphObjectList.class; } }; return coerceValueToExpectedType(value, GraphObjectList.class, parameterizedType); } else if (methodName.equals(SETPROPERTY_METHOD)) { return setJSONProperty(args); } else if (methodName.equals(REMOVEPROPERTY_METHOD)) { this.state.remove((String) args[0]); return null; } return throwUnexpectedMethodSignature(method); } private Object createGraphObjectsFromParameters(CreateGraphObject createGraphObject, Object value) { if (createGraphObject != null && !Utility.isNullOrEmpty(createGraphObject.value())) { String propertyName = createGraphObject.value(); if (List.class.isAssignableFrom(value.getClass())) { GraphObjectList graphObjects = GraphObject.Factory.createList(GraphObject.class); @SuppressWarnings("unchecked") List values = (List)value; for (Object obj : values) { GraphObject graphObject = GraphObject.Factory.create(); graphObject.setProperty(propertyName, obj); graphObjects.add(graphObject); } value = graphObjects; } else { GraphObject graphObject = GraphObject.Factory.create(); graphObject.setProperty(propertyName, value); value = graphObject; } } return value; } private final Object proxyGraphObjectGettersAndSetters(Method method, Object[] args) throws JSONException { String methodName = method.getName(); int parameterCount = method.getParameterTypes().length; PropertyName propertyNameOverride = method.getAnnotation(PropertyName.class); String key = propertyNameOverride != null ? propertyNameOverride.value() : convertCamelCaseToLowercaseWithUnderscores(methodName.substring(3)); // If it's a get or a set on a GraphObject-derived class, we can handle it. if (parameterCount == 0) { // Has to be a getter. ASSUMPTION: The GraphObject-derived class has been verified Object value = this.state.opt(key); Class expectedType = method.getReturnType(); Type genericReturnType = method.getGenericReturnType(); ParameterizedType parameterizedReturnType = null; if (genericReturnType instanceof ParameterizedType) { parameterizedReturnType = (ParameterizedType) genericReturnType; } value = coerceValueToExpectedType(value, expectedType, parameterizedReturnType); return value; } else if (parameterCount == 1) { // Has to be a setter. ASSUMPTION: The GraphObject-derived class has been verified CreateGraphObject createGraphObjectAnnotation = method.getAnnotation(CreateGraphObject.class); Object value = createGraphObjectsFromParameters(createGraphObjectAnnotation, args[0]); // If this is a wrapped object, store the underlying JSONObject instead, in order to serialize // correctly. value = getUnderlyingJSONObject(value); this.state.putOpt(key, value); return null; } return throwUnexpectedMethodSignature(method); } private Object setJSONProperty(Object[] args) { String name = (String) args[0]; Object property = args[1]; Object value = getUnderlyingJSONObject(property); try { state.putOpt(name, value); } catch (JSONException e) { throw new IllegalArgumentException(e); } return null; } } private final static class GraphObjectListImpl extends AbstractList implements GraphObjectList { private final JSONArray state; private final Class itemType; public GraphObjectListImpl(JSONArray state, Class itemType) { Validate.notNull(state, "state"); Validate.notNull(itemType, "itemType"); this.state = state; this.itemType = itemType; } @Override public String toString() { return String.format("GraphObjectList{itemType=%s, state=%s}", itemType.getSimpleName(), state); } @Override public void add(int location, T object) { // We only support adding at the end of the list, due to JSONArray restrictions. if (location < 0) { throw new IndexOutOfBoundsException(); } else if (location < size()) { throw new UnsupportedOperationException("Only adding items at the end of the list is supported."); } put(location, object); } @Override public T set(int location, T object) { checkIndex(location); T result = get(location); put(location, object); return result; } @Override public int hashCode() { return state.hashCode(); } @Override public boolean equals(Object obj) { if (obj == null) { return false; } else if (this == obj) { return true; } else if (getClass() != obj.getClass()) { return false; } @SuppressWarnings("unchecked") GraphObjectListImpl other = (GraphObjectListImpl) obj; return state.equals(other.state); } @SuppressWarnings("unchecked") @Override public T get(int location) { checkIndex(location); Object value = state.opt(location); // Class expectedType = method.getReturnType(); // Type genericType = method.getGenericReturnType(); T result = (T) coerceValueToExpectedType(value, itemType, null); return result; } @Override public int size() { return state.length(); } @Override public final GraphObjectList castToListOf(Class graphObjectClass) { if (GraphObject.class.isAssignableFrom(itemType)) { if (graphObjectClass.isAssignableFrom(itemType)) { @SuppressWarnings("unchecked") GraphObjectList result = (GraphObjectList)this; return result; } return createList(state, graphObjectClass); } else { throw new FacebookGraphObjectException("Can't cast GraphObjectCollection of non-GraphObject type " + itemType); } } @Override public final JSONArray getInnerJSONArray() { return state; } @Override public void clear() { throw new UnsupportedOperationException(); } @Override public boolean remove(Object o) { throw new UnsupportedOperationException(); } @Override public boolean removeAll(Collection c) { throw new UnsupportedOperationException(); } @Override public boolean retainAll(Collection c) { throw new UnsupportedOperationException(); } private void checkIndex(int index) { if (index < 0 || index >= state.length()) { throw new IndexOutOfBoundsException(); } } private void put(int index, T obj) { Object underlyingObject = getUnderlyingJSONObject(obj); try { state.put(index, underlyingObject); } catch (JSONException e) { throw new IllegalArgumentException(e); } } } } }