objectstreamclass_1_3_1.java

JAVA的一些源码 JAVA2 STANDARD EDITION DEVELOPMENT KIT 5.0

/*
 * @(#)ObjectStreamClass_1_3_1.java	1.6 04/01/12
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Licensed Materials - Property of IBM
 * RMI-IIOP v1.0
 * Copyright IBM Corp. 1998 1999  All Rights Reserved
 *
 * US Government Users Restricted Rights - Use, duplication or
 * disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
 */

package com.sun.corba.se.impl.orbutil;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.DigestOutputStream;
import java.security.AccessController;
import java.security.PrivilegedExceptionAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedAction;

import java.lang.reflect.Modifier;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Constructor;
import java.lang.reflect.Proxy;
import java.lang.reflect.InvocationTargetException;

import java.io.IOException;
import java.io.DataOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.InvalidClassException;
import java.io.Serializable;

import java.util.Arrays;
import java.util.Comparator;
import java.util.Hashtable;

import org.omg.CORBA.ValueMember;

import com.sun.corba.se.impl.io.ValueUtility;
import com.sun.corba.se.impl.io.ObjectStreamClass;

/**
 * This is duplicated here to preserve the JDK 1.3.1FCS behavior
 * of calculating the OMG hash code incorrectly when serialPersistentFields
 * is used, but some of the fields no longer exist in the class itself.
 *
 * We have to duplicate it since we aren't allowed to modify the
 * com.sun.corba.se.impl.io version further, and can't make it
 * public outside of its package for security reasons.
 */
/**
 * A ObjectStreamClass_1_3_1 describes a class that can be serialized to a stream
 * or a class that was serialized to a stream.  It contains the name
 * and the serialVersionUID of the class.
 * <br>
 * The ObjectStreamClass_1_3_1 for a specific class loaded in this Java VM can
 * be found using the lookup method.
 *
 * @author  Roger Riggs
 * @(#)ObjectStreamClass_1_3_1.java	1.17 99/06/07
 * @since   JDK1.1
 */
public class ObjectStreamClass_1_3_1 implements java.io.Serializable {

    public static final long kDefaultUID = -1;

    private static Object noArgsList[] = {};
    private static Class noTypesList[] = {};
	
    private static Hashtable translatedFields;

    /** Find the descriptor for a class that can be serialized.  Null
     * is returned if the specified class does not implement
     * java.io.Serializable or java.io.Externalizable.
     */
    static final ObjectStreamClass_1_3_1 lookup(Class cl)
    {
	ObjectStreamClass_1_3_1 desc = lookupInternal(cl);
	if (desc.isSerializable() || desc.isExternalizable())
	    return desc;
	return null;
    }

    /*
     * Find the class descriptor for the specified class.
     * Package access only so it can be called from ObjectIn/OutStream.
     */
    static ObjectStreamClass_1_3_1 lookupInternal(Class cl)
    {
	/* Synchronize on the hashtable so no two threads will do
	 * this at the same time.
	 */
	ObjectStreamClass_1_3_1 desc = null;
	synchronized (descriptorFor) {
	    /* Find the matching descriptor if it already known */
	    desc = findDescriptorFor(cl);
	    if (desc != null) {
		return desc;
	    }

                /* Check if it's serializable */
                boolean serializable = classSerializable.isAssignableFrom(cl);
                /* If the class is only Serializable,
                 * lookup the descriptor for the superclass.
                 */
                ObjectStreamClass_1_3_1 superdesc = null;
                if (serializable) {
                    Class superclass = cl.getSuperclass();
                    if (superclass != null)
                        superdesc = lookup(superclass);
                }

                /* Check if its' externalizable.
                 * If it's Externalizable, clear the serializable flag.
                 * Only one or the other may be set in the protocol.
                 */
                boolean externalizable = false;
                if (serializable) {
                    externalizable =
                        ((superdesc != null) && superdesc.isExternalizable()) ||
                        classExternalizable.isAssignableFrom(cl);
                    if (externalizable) {
                        serializable = false;
                    }
                }

	    /* Create a new version descriptor,
	     * it put itself in the known table.
	     */
	    desc = new ObjectStreamClass_1_3_1(cl, superdesc,
					 serializable, externalizable);
	}
	desc.init();
	return desc;
    }

    /**
     * The name of the class described by this descriptor.
     */
    public final String getName() {
	return name;
    }

    /**
     * Return the serialVersionUID for this class.
     * The serialVersionUID defines a set of classes all with the same name
     * that have evolved from a common root class and agree to be serialized
     * and deserialized using a common format.
     */
    public static final long getSerialVersionUID( java.lang.Class clazz) {
	ObjectStreamClass_1_3_1 theosc = ObjectStreamClass_1_3_1.lookup( clazz );
        if( theosc != null )
	{
		return theosc.getSerialVersionUID( );
	}
	return 0;
    }

    /**
     * Return the serialVersionUID for this class.
     * The serialVersionUID defines a set of classes all with the same name
     * that have evolved from a common root class and agree to be serialized
     * and deserialized using a common format.
     */
    public final long getSerialVersionUID() {
	return suid;
    }

    /**
     * Return the serialVersionUID string for this class.
     * The serialVersionUID defines a set of classes all with the same name
     * that have evolved from a common root class and agree to be serialized
     * and deserialized using a common format.
     */
    public final String getSerialVersionUIDStr() {
	if (suidStr == null)
	    suidStr = Long.toHexString(suid).toUpperCase();
	return suidStr;
    }

    /**
     * Return the actual (computed) serialVersionUID for this class.
     */
    public static final long getActualSerialVersionUID( java.lang.Class clazz )
    {
	ObjectStreamClass_1_3_1 theosc = ObjectStreamClass_1_3_1.lookup( clazz );
	if( theosc != null )
	{
		return theosc.getActualSerialVersionUID( );
	}
	return 0;
    }

    /**
     * Return the actual (computed) serialVersionUID for this class.
     */
    public final long getActualSerialVersionUID() {
	return actualSuid;
    }

    /**
     * Return the actual (computed) serialVersionUID for this class.
     */
    public final String getActualSerialVersionUIDStr() {
	if (actualSuidStr == null)
	    actualSuidStr = Long.toHexString(actualSuid).toUpperCase();
	return actualSuidStr;
    }

    /**
     * Return the class in the local VM that this version is mapped to.
     * Null is returned if there is no corresponding local class.
     */
    public final Class forClass() {
	return ofClass;
    }

    /**
     * Return an array of the fields of this serializable class.
     * @return an array containing an element for each persistent
     * field of this class. Returns an array of length zero if
     * there are no fields.
     * @since JDK1.2
     */
    public ObjectStreamField[] getFields() {
    	// Return a copy so the caller can't change the fields.
	if (fields.length > 0) {
	    ObjectStreamField[] dup = new ObjectStreamField[fields.length];
	    System.arraycopy(fields, 0, dup, 0, fields.length);
	    return dup;
	} else {
	    return fields;
	}
    }

    public boolean hasField(ValueMember field){

	for (int i = 0; i < fields.length; i++){
	    try{
		if (fields[i].getName().equals(field.name)) {

		    if (fields[i].getSignature().equals(ValueUtility.getSignature(field)))
			return true;
		}
	    }
	    catch(Throwable t){}
	}
	return false;
    }

    /* Avoid unnecessary allocations. */
    final ObjectStreamField[] getFieldsNoCopy() {
	return fields;
    }

    /**
     * Get the field of this class by name.
     * @return The ObjectStreamField object of the named field or null if there
     * is no such named field.
     */
    public final ObjectStreamField getField(String name) {
    	/* Binary search of fields by name.
	 */
    	for (int i = fields.length-1; i >= 0; i--) {
    	    if (name.equals(fields[i].getName())) {
    	    	return fields[i];
	    }
    	}
	return null;
    }

    public Serializable writeReplace(Serializable value) {
	if (writeReplaceObjectMethod != null) {
	    try {
		return (Serializable) writeReplaceObjectMethod.invoke(value,noArgsList);
	    }
	    catch(Throwable t) {
		throw new RuntimeException(t.getMessage());
	    }
	}
	else return value;
    }

    public Object readResolve(Object value) {
	if (readResolveObjectMethod != null) {
	    try {
		return readResolveObjectMethod.invoke(value,noArgsList);
	    }
	    catch(Throwable t) {
		throw new RuntimeException(t.getMessage());
	    }
	}
	else return value;
    }

    /**
     * Return a string describing this ObjectStreamClass_1_3_1.
     */
    public final String toString() {
	StringBuffer sb = new StringBuffer();

	sb.append(name);
	sb.append(": static final long serialVersionUID = ");
	sb.append(Long.toString(suid));
	sb.append("L;");
	return sb.toString();
    }

    /*
     * Create a new ObjectStreamClass_1_3_1 from a loaded class.
     * Don't call this directly, call lookup instead.
     */
    private ObjectStreamClass_1_3_1(java.lang.Class cl, ObjectStreamClass_1_3_1 superdesc,
			      boolean serial, boolean extern)
    {
	ofClass = cl;		/* created from this class */

        if (Proxy.isProxyClass(cl)) {
            forProxyClass = true;
        }

	name = cl.getName();
	superclass = superdesc;
	serializable = serial;
        if (!forProxyClass) {
            // proxy classes are never externalizable
            externalizable = extern;
        }

	/*
	 * Enter this class in the table of known descriptors.
	 * Otherwise, when the fields are read it may recurse
	 * trying to find the descriptor for itself.
	 */
	insertDescriptorFor(this);

        /*
         * The remainder of initialization occurs in init(), which is called
         * after the lock on the global class descriptor table has been
         * released.
         */
    }

    /*
     * Initialize class descriptor.  This method is only invoked on class
     * descriptors created via calls to lookupInternal().  This method is kept
     * separate from the ObjectStreamClass_1_3_1 constructor so that lookupInternal
     * does not have to hold onto a global class descriptor table lock while the
     * class descriptor is being initialized (see bug 4165204).
     */


    private void init() {
      synchronized (lock) {

	final Class cl = ofClass;
 
	if (fields != null) // already initialized
                return;


	if (!serializable ||
	    externalizable ||
	    forProxyClass ||
	    name.equals("java.lang.String")) {
	    fields = NO_FIELDS;
	} else if (serializable) {

            /* Ask for permission to override field access checks.
             */
            AccessController.doPrivileged(new PrivilegedAction() {
                public Object run() {
		/* Fill in the list of persistent fields.
		 * If it is declared, use the declared serialPersistentFields.
		 * Otherwise, extract the fields from the class itself.
		 */
		try {
                    Field pf = cl.getDeclaredField("serialPersistentFields");
	            // serial bug 7; the serialPersistentFields were not
	            // being read and stored as Accessible bit was not set
		    pf.setAccessible(true);
	            // serial bug 7; need to find if the field is of type
	            // java.io.ObjectStreamField
                    java.io.ObjectStreamField[] f =
                           (java.io.ObjectStreamField[])pf.get(cl);
		    int mods = pf.getModifiers();
		    if ((Modifier.isPrivate(mods)) &&
			(Modifier.isStatic(mods)) &&
			(Modifier.isFinal(mods)))
	            {
			fields = (ObjectStreamField[])translateFields((Object[])pf.get(cl));
		    }
		} catch (NoSuchFieldException e) {
		    fields = null;
		} catch (IllegalAccessException e) {
		    fields = null;
		} catch (IllegalArgumentException e) {
		    fields = null;
                } catch (ClassCastException e) {
                    /* Thrown if a field serialPersistentField exists
                     * but it is not of type ObjectStreamField.
                     */
                    fields = null;
                }


		if (fields == null) {
		    /* Get all of the declared fields for this
		     * Class. setAccessible on all fields so they
		     * can be accessed later.  Create a temporary
		     * ObjectStreamField array to hold each
		     * non-static, non-transient field. Then copy the
		     * temporary array into an array of the correct