com.google.gwtjsonrpc.server.CallDeserializer.java Source code

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Here is the source code for com.google.gwtjsonrpc.server.CallDeserializer.java

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// Copyright 2008 Google Inc.
//
// 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.google.gwtjsonrpc.server;

import com.google.gson.InstanceCreator;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;

import java.lang.reflect.Type;

final class CallDeserializer<CallType extends ActiveCall>
        implements JsonDeserializer<CallType>, InstanceCreator<CallType> {
    private final CallType req;
    private final JsonServlet<? extends ActiveCall> server;

    CallDeserializer(final CallType call, final JsonServlet<CallType> jsonServlet) {
        req = call;
        server = jsonServlet;
    }

    public CallType createInstance(final Type type) {
        return req;
    }

    public CallType deserialize(final JsonElement json, final Type typeOfT,
            final JsonDeserializationContext context) throws JsonParseException, NoSuchRemoteMethodException {
        if (!json.isJsonObject()) {
            throw new JsonParseException("Expected object");
        }

        final JsonObject in = json.getAsJsonObject();
        req.id = in.get("id");

        final JsonElement jsonrpc = in.get("jsonrpc");
        final JsonElement version = in.get("version");
        if (isString(jsonrpc) && version == null) {
            final String v = jsonrpc.getAsString();
            if ("2.0".equals(v)) {
                req.versionName = "jsonrpc";
                req.versionValue = jsonrpc;
            } else {
                throw new JsonParseException("Expected jsonrpc=2.0");
            }

        } else if (isString(version) && jsonrpc == null) {
            final String v = version.getAsString();
            if ("1.1".equals(v)) {
                req.versionName = "version";
                req.versionValue = version;
            } else {
                throw new JsonParseException("Expected version=1.1");
            }
        } else {
            throw new JsonParseException("Expected version=1.1 or jsonrpc=2.0");
        }

        final JsonElement method = in.get("method");
        if (!isString(method)) {
            throw new JsonParseException("Expected method name as string");
        }

        req.method = server.lookupMethod(method.getAsString());
        if (req.method == null) {
            throw new NoSuchRemoteMethodException();
        }

        final JsonElement callback = in.get("callback");
        if (callback != null) {
            if (!isString(callback)) {
                throw new JsonParseException("Expected callback as string");
            }
            req.callback = callback.getAsString();
        }

        final JsonElement xsrfKey = in.get("xsrfKey");
        if (xsrfKey != null) {
            if (!isString(xsrfKey)) {
                throw new JsonParseException("Expected xsrfKey as string");
            }
            req.xsrfKeyIn = xsrfKey.getAsString();
        }

        final Type[] paramTypes = req.method.getParamTypes();
        final JsonElement params = in.get("params");
        if (params != null) {
            if (!params.isJsonArray()) {
                throw new JsonParseException("Expected params array");
            }

            final JsonArray paramsArray = params.getAsJsonArray();
            if (paramsArray.size() != paramTypes.length) {
                throw new JsonParseException("Expected " + paramTypes.length + " parameter values in params array");
            }

            final Object[] r = new Object[paramTypes.length];
            for (int i = 0; i < r.length; i++) {
                final JsonElement v = paramsArray.get(i);
                if (v != null) {
                    r[i] = context.deserialize(v, paramTypes[i]);
                }
            }
            req.params = r;
        } else {
            if (paramTypes.length != 0) {
                throw new JsonParseException("Expected params array");
            }
            req.params = JsonServlet.NO_PARAMS;
        }

        return req;
    }

    private static boolean isString(final JsonElement e) {
        return e != null && e.isJsonPrimitive() && e.getAsJsonPrimitive().isString();
    }
}