objectstreamclass.java

来自「JAVA的一些源码 JAVA2 STANDARD EDITION DEVELO」· Java 代码 · 共 1,769 行 · 第 1/4 页

	String type = null;
	if (clazz.isArray()) {
	    Class cl = clazz;
	    int dimensions = 0;
	    while (cl.isArray()) {
		dimensions++;
		cl = cl.getComponentType();
	    }
	    StringBuffer sb = new StringBuffer();
	    for (int i = 0; i < dimensions; i++) {
		sb.append("[");
	    }
	    sb.append(getSignature(cl));
	    type = sb.toString();
	} else if (clazz.isPrimitive()) {
	    if (clazz == Integer.TYPE) {
		type = "I";
	    } else if (clazz == Byte.TYPE) {
		type = "B";
	    } else if (clazz == Long.TYPE) {
		type = "J";
	    } else if (clazz == Float.TYPE) {
		type = "F";
	    } else if (clazz == Double.TYPE) {
		type = "D";
	    } else if (clazz == Short.TYPE) {
		type = "S";
	    } else if (clazz == Character.TYPE) {
		type = "C";
	    } else if (clazz == Boolean.TYPE) {
		type = "Z";
	    } else if (clazz == Void.TYPE) {
		type = "V";
	    }
	} else {
	    type = "L" + clazz.getName().replace('.', '/') + ";";
	}
	return type;
    }

    /*
     * Compute the JVM method descriptor for the method.
     */
    static String getSignature(Method meth) {
	StringBuffer sb = new StringBuffer();

	sb.append("(");

	Class[] params = meth.getParameterTypes(); // avoid clone
	for (int j = 0; j < params.length; j++) {
	    sb.append(getSignature(params[j]));
	}
	sb.append(")");
	sb.append(getSignature(meth.getReturnType()));
	return sb.toString();
    }

    /*
     * Compute the JVM constructor descriptor for the constructor.
     */
    static String getSignature(Constructor cons) {
	StringBuffer sb = new StringBuffer();

	sb.append("(");

	Class[] params = cons.getParameterTypes(); // avoid clone
	for (int j = 0; j < params.length; j++) {
	    sb.append(getSignature(params[j]));
	}
	sb.append(")V");
	return sb.toString();
    }

    static private SoftCache descriptorFor = new SoftCache() ;

    private static Field[] getDeclaredFields(final Class clz) {
        return (Field[]) AccessController.doPrivileged(new PrivilegedAction() {
            public Object run() {
                return clz.getDeclaredFields();
            }
        });
    }


    /*
     * The name of this descriptor
     */
    private String name;

    /*
     * The descriptor of the supertype.
     */
    private ObjectStreamClass superclass;

    /*
     * Flags for Serializable and Externalizable.
     */
    private boolean serializable;
    private boolean externalizable;

    /*
     * Array of persistent fields of this class, sorted by
     * type and name.
     */
    private ObjectStreamField[] fields;

    /*
     * Class that is a descriptor for in this virtual machine.
     */
    private Class ofClass;

    /*
     * True if descriptor for a proxy class.
     */
    boolean forProxyClass;


    /*
     * SerialVersionUID for this class.
     */
    private long suid = kDefaultUID;
    private String suidStr = null;

    /*
     * Actual (computed) SerialVersionUID for this class.
     */
    private long actualSuid = kDefaultUID;
    private String actualSuidStr = null;

    /*
     * The total number of bytes of primitive fields.
     * The total number of object fields.
     */
    int primBytes;
    int objFields;

    /**
     * Flag indicating whether or not this instance has 
     * successfully completed initialization.  This is to
     * try to fix bug 4373844.  Working to move to
     * reusing java.io.ObjectStreamClass for JDK 1.5.
     */
    private boolean initialized = false;

    /* Internal lock object. */
    private Object lock = new Object();

    /* In JDK 1.1, external data was not written in block mode.
     * As of JDK 1.2, external data is written in block data mode. This
     * flag enables JDK 1.2 to be able to read JDK 1.1 written external data.
     *
     * @since JDK 1.2
     */
    private boolean hasExternalizableBlockData;
    Method writeObjectMethod;
    Method readObjectMethod;
    private Method writeReplaceObjectMethod;
    private Method readResolveObjectMethod;
    private Constructor cons ;

    /**
     * Beginning in Java to IDL ptc/02-01-12, RMI-IIOP has a
     * stream format version 2 which puts a fake valuetype around
     * a Serializable's optional custom data.  This valuetype has
     * a special repository ID made from the Serializable's
     * information which we are pre-computing and
     * storing here.
     */
    private String rmiiiopOptionalDataRepId = null;

    /*
     * ObjectStreamClass that this one was built from.
     */
    private ObjectStreamClass localClassDesc;

    /* Find out if the class has a static class initializer <clinit> */
    private static Method hasStaticInitializerMethod = null;
    /**
     * Returns true if the given class defines a static initializer method,
     * false otherwise.
     */
    private static boolean hasStaticInitializer(Class cl) {
        if (hasStaticInitializerMethod == null) {
            Class classWithThisMethod = null;
            
            try {
                try {
                    // When using rip-int with Merlin or when this is a Merlin
                    // workspace, the method we want is in sun.misc.ClassReflector
                    // and absent from java.io.ObjectStreamClass.
                    //
                    // When compiling rip-int with JDK 1.3.x, we have to get it
                    // from java.io.ObjectStreamClass.
                    classWithThisMethod = Class.forName("sun.misc.ClassReflector");
                } catch (ClassNotFoundException cnfe) {
                    // Do nothing.  This is either not a Merlin workspace,
                    // or rip-int is being compiled with something other than
                    // Merlin, probably JDK 1.3.  Fall back on java.io.ObjectStreaClass.
                }
                if (classWithThisMethod == null)
                    classWithThisMethod = java.io.ObjectStreamClass.class;
                
                hasStaticInitializerMethod =
                    classWithThisMethod.getDeclaredMethod("hasStaticInitializer",
                                                          new Class[] { Class.class });
            } catch (NoSuchMethodException ex) {
            }
            
            if (hasStaticInitializerMethod == null) {
		// XXX I18N, logging needed
                throw new InternalError("Can't find hasStaticInitializer method on "
                                        + classWithThisMethod.getName());
            }
            hasStaticInitializerMethod.setAccessible(true);
        }

        try {
            Boolean retval = (Boolean)
                hasStaticInitializerMethod.invoke(null, new Object[] { cl });
            return retval.booleanValue();
        } catch (Exception ex) {
	    // XXX I18N, logging needed
            InternalError ie = new InternalError( "Error invoking hasStaticInitializer" ) ;
	    ie.initCause( ex ) ;
	    throw ie ;
        }
    }


    /* The Class Object for java.io.Serializable */
    private static Class classSerializable = null;
    private static Class classExternalizable = null;

    /*
     * Resolve java.io.Serializable at load time.
     */
    static {
	try {
	    classSerializable = Class.forName("java.io.Serializable");
	    classExternalizable = Class.forName("java.io.Externalizable");
	} catch (Throwable e) {
	    System.err.println("Could not load java.io.Serializable or java.io.Externalizable.");
	}
    }

    /** use serialVersionUID from JDK 1.1. for interoperability */
    private static final long serialVersionUID = -6120832682080437368L;

    /**
     * Set serialPersistentFields of a Serializable class to this value to
     * denote that the class has no Serializable fields.
     */
    public static final ObjectStreamField[] NO_FIELDS =
        new ObjectStreamField[0];

    /*
     * Entries held in the Cache of known ObjectStreamClass objects.
     * Entries are chained together with the same hash value (modulo array size).
     */
    private static class ObjectStreamClassEntry // extends java.lang.ref.SoftReference
    {
	ObjectStreamClassEntry(ObjectStreamClass c) {
	    //super(c);
	    this.c = c;
	}
	ObjectStreamClassEntry next;

	public Object get()
	{
	    return c;
	}
	private ObjectStreamClass c;
    }

    /*
     * Comparator object for Classes and Interfaces
     */
    private static Comparator compareClassByName =
    	new CompareClassByName();

    private static class CompareClassByName implements Comparator {
	public int compare(Object o1, Object o2) {
	    Class c1 = (Class)o1;
	    Class c2 = (Class)o2;
	    return (c1.getName()).compareTo(c2.getName());
	}
    }

    /**
     * Comparator for ObjectStreamFields by name
     */
    private final static Comparator compareObjStrFieldsByName
        = new CompareObjStrFieldsByName();

    private static class CompareObjStrFieldsByName implements Comparator {
        public int compare(Object o1, Object o2) {
            ObjectStreamField osf1 = (ObjectStreamField)o1;
            ObjectStreamField osf2 = (ObjectStreamField)o2;

            return osf1.getName().compareTo(osf2.getName());
        }
    }

    /*
     * Comparator object for Members, Fields, and Methods
     */
    private static Comparator compareMemberByName =
    	new CompareMemberByName();

    private static class CompareMemberByName implements Comparator {
	public int compare(Object o1, Object o2) {
	    String s1 = ((Member)o1).getName();
	    String s2 = ((Member)o2).getName();

	    if (o1 instanceof Method) {
		s1 += getSignature((Method)o1);
		s2 += getSignature((Method)o2);
	    } else if (o1 instanceof Constructor) {
		s1 += getSignature((Constructor)o1);
		s2 += getSignature((Constructor)o2);
	    }
	    return s1.compareTo(s2);
	}
    }

    /* It is expensive to recompute a method or constructor signature
       many times, so compute it only once using this data structure. */
    private static class MethodSignature implements Comparator {
	Member member;
	String signature;      // cached parameter signature

	/* Given an array of Method or Constructor members,
	   return a sorted array of the non-private members.*/
	/* A better implementation would be to implement the returned data
	   structure as an insertion sorted link list.*/
	static MethodSignature[] removePrivateAndSort(Member[] m) {
	    int numNonPrivate = 0;
	    for (int i = 0; i < m.length; i++) {
		if (! Modifier.isPrivate(m[i].getModifiers())) {
		    numNonPrivate++;
		}
	    }
	    MethodSignature[] cm = new MethodSignature[numNonPrivate];
	    int cmi = 0;
	    for (int i = 0; i < m.length; i++) {
		if (! Modifier.isPrivate(m[i].getModifiers())) {
		    cm[cmi] = new MethodSignature(m[i]);
		    cmi++;
		}
	    }
	    if (cmi > 0)
		Arrays.sort(cm, cm[0]);
	    return cm;
	}

	/* Assumes that o1 and o2 are either both methods
	   or both constructors.*/
	public int compare(Object o1, Object o2) {
	    /* Arrays.sort calls compare when o1 and o2 are equal.*/
	    if (o1 == o2)
		return 0;

	    MethodSignature c1 = (MethodSignature)o1;
	    MethodSignature c2 = (MethodSignature)o2;

	    int result;
	    if (isConstructor()) {
		result = c1.signature.compareTo(c2.signature);
	    } else { // is a Method.
		result = c1.member.getName().compareTo(c2.member.getName());
		if (result == 0)
		    result = c1.signature.compareTo(c2.signature);
	    }
	    return result;
	}

	final private boolean isConstructor() {
	    return member instanceof Constructor;
	}
	private MethodSignature(Member m) {
	    member = m;
	    if (isConstructor()) {
		signature = ObjectStreamClass.getSignature((Constructor)m);
	    } else {
		signature = ObjectStreamClass.getSignature((Method)m);
	    }
	}
    }

    /**
     * Returns non-static, non-abstract method with given signature provided it
     * is defined by or accessible (via inheritance) by the given class, or
     * null if no match found.  Access checks are disabled on the returned
     * method (if any).
     *
     * Copied from the Merlin java.io.ObjectStreamClass.
     */
    private static Method getInheritableMethod(Class cl, String name,
					       Class[] argTypes,
					       Class returnType)
    {
	Method meth = null;
	Class defCl = cl;
	while (defCl != null) {
	    try {
		meth = defCl.getDeclaredMethod(name, argTypes);
		break;
	    } catch (NoSuchMethodException ex) {
		defCl = defCl.getSuperclass();
	    }
	}

	if ((meth == null) || (meth.getReturnType() != returnType)) {
	    return null;
	}
	meth.setAccessible(true);
	int mods = meth.getModifiers();
	if ((mods & (Modifier.STATIC | Modifier.ABSTRACT)) != 0) {
	    return null;
	} else if ((mods & (Modifier.PUBLIC | Modifier.PROTECTED)) != 0) {
	    return meth;
	} else if ((mods & Modifier.PRIVATE) != 0) {
	    return (cl == defCl) ? meth : null;
	} else {
	    return packageEquals(cl, defCl) ? meth : null;
	}
    }

    /**
     * Returns true if classes are defined in the same package, false
     * otherwise.
     *
     * Copied from the Merlin java.io.ObjectStreamClass.
     */
    private static boolean packageEquals(Class cl1, Class cl2) {
	Package pkg1 = cl1.getPackage(), pkg2 = cl2.getPackage();
	return ((pkg1 == pkg2) || ((pkg1 != null) && (pkg1.equals(pkg2))));
    }
}