com.metaparadigm.jsonrpc.BeanSerializer.java Source code

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/*
 * JSON-RPC-Java - a JSON-RPC to Java Bridge with dynamic invocation
 *
 * $Id: BeanSerializer.java,v 1.7.2.2 2006/03/06 12:39:21 mclark Exp $
 *
 * 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 com.metaparadigm.jsonrpc;

import java.util.Map;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.logging.Logger;
import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;
import java.beans.Introspector;
import java.beans.IntrospectionException;
import java.beans.PropertyDescriptor;
import java.beans.BeanInfo;

import org.json.JSONException;
import org.json.JSONObject;

public class BeanSerializer extends AbstractSerializer {
    private final static long serialVersionUID = 1;

    private final static Logger log = Logger.getLogger(BeanSerializer.class.getName());

    private static HashMap beanCache = new HashMap();

    private static Class[] _serializableClasses = new Class[] {};
    private static Class[] _JSONClasses = new Class[] {};

    public Class[] getSerializableClasses() {
        return _serializableClasses;
    }

    public Class[] getJSONClasses() {
        return _JSONClasses;
    }

    @Override
    public boolean canSerialize(Class clazz, Class jsonClazz) {
        return (!clazz.isArray() && !clazz.isPrimitive() && !clazz.isInterface()
                && (jsonClazz == null || jsonClazz == JSONObject.class));
    }

    protected static class BeanData {
        // in absence of getters and setters, these fields are
        // public to allow subclasses to access.
        public BeanInfo beanInfo;
        public HashMap readableProps;
        public HashMap writableProps;
    }

    protected static class BeanSerializerState {
        // in absence of getters and setters, these fields are
        // public to allow subclasses to access.

        // Circular reference detection
        public HashSet beanSet = new HashSet();
    }

    public static BeanData analyzeBean(Class clazz) throws IntrospectionException {
        //      log.info("analyzing " + clazz.getName());
        BeanData bd = new BeanData();
        bd.beanInfo = Introspector.getBeanInfo(clazz, Object.class);
        PropertyDescriptor props[] = bd.beanInfo.getPropertyDescriptors();
        bd.readableProps = new HashMap();
        bd.writableProps = new HashMap();
        for (int i = 0; i < props.length; i++) {
            if (props[i].getWriteMethod() != null) {
                bd.writableProps.put(props[i].getName(), props[i].getWriteMethod());
            }
            if (props[i].getReadMethod() != null) {
                bd.readableProps.put(props[i].getName(), props[i].getReadMethod());
            }
        }
        return bd;
    }

    public static BeanData getBeanData(Class clazz) throws IntrospectionException {
        BeanData bd;
        synchronized (beanCache) {
            bd = (BeanData) beanCache.get(clazz);
            if (bd == null) {
                bd = analyzeBean(clazz);
                beanCache.put(clazz, bd);
            }
        }
        return bd;
    }

    public ObjectMatch tryUnmarshall(SerializerState state, Class clazz, Object o) throws UnmarshallException {
        JSONObject jso = (JSONObject) o;
        BeanData bd = null;
        try {
            bd = getBeanData(clazz);
        } catch (IntrospectionException e) {
            throw new UnmarshallException(clazz.getName() + " is not a bean");
        }

        int match = 0, mismatch = 0;
        Iterator i = bd.writableProps.entrySet().iterator();
        while (i.hasNext()) {
            Map.Entry ent = (Map.Entry) i.next();
            String prop = (String) ent.getKey();
            Method method = (Method) ent.getValue();
            if (jso.has(prop))
                match++;
            else
                mismatch++;
        }
        if (match == 0)
            throw new UnmarshallException("bean has no matches");

        ObjectMatch m = null, tmp = null;
        i = jso.keys();
        while (i.hasNext()) {
            String field = (String) i.next();
            Method setMethod = (Method) bd.writableProps.get(field);
            if (setMethod != null) {
                try {
                    Class param[] = setMethod.getParameterTypes();
                    if (param.length != 1)
                        throw new UnmarshallException("bean " + clazz.getName() + " method " + setMethod.getName()
                                + " does not have one arg");
                    tmp = ser.tryUnmarshall(state, param[0], jso.get(field));
                    if (m == null)
                        m = tmp;
                    else
                        m = m.max(tmp);
                } catch (UnmarshallException e) {
                    throw new UnmarshallException("bean " + clazz.getName() + " " + e.getMessage());
                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            } else {
                mismatch++;
            }
        }
        return m.max(new ObjectMatch(mismatch));
    }

    public Object unmarshall(SerializerState state, Class clazz, Object o) throws UnmarshallException {
        JSONObject jso = (JSONObject) o;
        BeanData bd = null;
        try {
            bd = getBeanData(clazz);
        } catch (IntrospectionException e) {
            throw new UnmarshallException(clazz.getName() + " is not a bean");
        }
        if (ser.isDebug())
            log.fine("instantiating " + clazz.getName());
        Object instance = null;
        try {
            instance = clazz.newInstance();
        } catch (Exception e) {
            throw new UnmarshallException("can't instantiate bean " + clazz.getName() + ": " + e.getMessage());
        }
        Object invokeArgs[] = new Object[1];
        Object fieldVal = null;
        Iterator i = jso.keys();
        while (i.hasNext()) {
            String field = (String) i.next();
            Method setMethod = (Method) bd.writableProps.get(field);
            if (setMethod != null) {
                try {
                    Class param[] = setMethod.getParameterTypes();
                    fieldVal = ser.unmarshall(state, param[0], jso.get(field));
                } catch (UnmarshallException e) {
                    throw new UnmarshallException("bean " + clazz.getName() + " " + e.getMessage());
                } catch (JSONException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                if (ser.isDebug())
                    log.fine("invoking " + setMethod.getName() + "(" + fieldVal + ")");
                invokeArgs[0] = fieldVal;
                try {
                    setMethod.invoke(instance, invokeArgs);
                } catch (Throwable e) {
                    if (e instanceof InvocationTargetException)
                        e = ((InvocationTargetException) e).getTargetException();
                    throw new UnmarshallException("bean " + clazz.getName() + "can't invoke " + setMethod.getName()
                            + ": " + e.getMessage());
                }
            }
        }
        return instance;
    }

    public Object marshall(SerializerState state, Object o) throws MarshallException {
        BeanSerializerState beanState;
        try {
            beanState = (BeanSerializerState) state.get(BeanSerializerState.class);
        } catch (Exception e) {
            throw new MarshallException("bean serializer internal error");
        }
        Integer identity = new Integer(System.identityHashCode(o));
        if (beanState.beanSet.contains(identity))
            throw new MarshallException("circular reference");
        beanState.beanSet.add(identity);

        BeanData bd = null;
        try {
            bd = getBeanData(o.getClass());
        } catch (IntrospectionException e) {
            throw new MarshallException(o.getClass().getName() + " is not a bean");
        }

        JSONObject val = new JSONObject();
        if (ser.getMarshallClassHints())
            try {
                val.put("javaClass", o.getClass().getName());
            } catch (JSONException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
        Iterator i = bd.readableProps.entrySet().iterator();
        Object args[] = new Object[0];
        Object result = null;
        while (i.hasNext()) {
            Map.Entry ent = (Map.Entry) i.next();
            String prop = (String) ent.getKey();
            Method getMethod = (Method) ent.getValue();
            if (ser.isDebug())
                log.fine("invoking " + getMethod.getName() + "()");
            try {
                result = getMethod.invoke(o, args);
            } catch (Throwable e) {
                if (e instanceof InvocationTargetException)
                    e = ((InvocationTargetException) e).getTargetException();
                throw new MarshallException("bean " + o.getClass().getName() + " can't invoke "
                        + getMethod.getName() + ": " + e.getMessage());
            }
            try {
                if (result != null || ser.getMarshallNullAttributes())
                    val.put(prop, ser.marshall(state, result));
            } catch (MarshallException e) {
                throw new MarshallException("bean " + o.getClass().getName() + " " + e.getMessage());
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

        beanState.beanSet.remove(identity);
        return val;
    }
}