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UnresolvedPermission.javaAPI DocJava SE 6 API18188Tue Jun 10 00:25:46 BST 2008java.security

UnresolvedPermission

public final class UnresolvedPermission extends Permission implements Serializable
The UnresolvedPermission class is used to hold Permissions that were "unresolved" when the Policy was initialized. An unresolved permission is one whose actual Permission class does not yet exist at the time the Policy is initialized (see below).

The policy for a Java runtime (specifying which permissions are available for code from various principals) is represented by a Policy object. Whenever a Policy is initialized or refreshed, Permission objects of appropriate classes are created for all permissions allowed by the Policy.

Many permission class types referenced by the policy configuration are ones that exist locally (i.e., ones that can be found on CLASSPATH). Objects for such permissions can be instantiated during Policy initialization. For example, it is always possible to instantiate a java.io.FilePermission, since the FilePermission class is found on the CLASSPATH.

Other permission classes may not yet exist during Policy initialization. For example, a referenced permission class may be in a JAR file that will later be loaded. For each such class, an UnresolvedPermission is instantiated. Thus, an UnresolvedPermission is essentially a "placeholder" containing information about the permission.

Later, when code calls AccessController.checkPermission on a permission of a type that was previously unresolved, but whose class has since been loaded, previously-unresolved permissions of that type are "resolved". That is, for each such UnresolvedPermission, a new object of the appropriate class type is instantiated, based on the information in the UnresolvedPermission.

To instantiate the new class, UnresolvedPermission assumes the class provides a zero, one, and/or two-argument constructor. The zero-argument constructor would be used to instantiate a permission without a name and without actions. A one-arg constructor is assumed to take a String name as input, and a two-arg constructor is assumed to take a String name and String actions as input. UnresolvedPermission may invoke a constructor with a null name and/or actions. If an appropriate permission constructor is not available, the UnresolvedPermission is ignored and the relevant permission will not be granted to executing code.

The newly created permission object replaces the UnresolvedPermission, which is removed.

Note that the getName method for an UnresolvedPermission returns the type (class name) for the underlying permission that has not been resolved.

see
java.security.Permission
see
java.security.Permissions
see
java.security.PermissionCollection
see
java.security.Policy
version
1.31 05/11/17
author
Roland Schemers

Fields Summary
private static final long
serialVersionUID
private static final Debug
debug
private String
type
The class name of the Permission class that will be created when this unresolved permission is resolved.
private String
name
The permission name.
private String
actions
The actions of the permission.
private transient Certificate[]
certs
private static final Class[]
PARAMS0
private static final Class[]
PARAMS1
private static final Class[]
PARAMS2
Constructors Summary
public UnresolvedPermission(String type, String name, String actions, Certificate[] certs)
Creates a new UnresolvedPermission containing the permission information needed later to actually create a Permission of the specified class, when the permission is resolved.

param
type the class name of the Permission class that will be created when this unresolved permission is resolved.
param
name the name of the permission.
param
actions the actions of the permission.
param
certs the certificates the permission's class was signed with. This is a list of certificate chains, where each chain is composed of a signer certificate and optionally its supporting certificate chain. Each chain is ordered bottom-to-top (i.e., with the signer certificate first and the (root) certificate authority last). The signer certificates are copied from the array. Subsequent changes to the array will not affect this UnsolvedPermission.


                                                                                                                                       
      
				 
				 
				 
    
	super(type);

	if (type == null) 
		throw new NullPointerException("type can't be null");

	this.type = type;
	this.name = name;
	this.actions = actions;
	if (certs != null) {
	    // Extract the signer certs from the list of certificates.
	    for (int i=0; i<certs.length; i++) {
		if (!(certs[i] instanceof X509Certificate)) {
		    // there is no concept of signer certs, so we store the
		    // entire cert array
		    this.certs =
			(java.security.cert.Certificate[])certs.clone();
		    break;
		}
	    }

	    if (this.certs == null) {
		// Go through the list of certs and see if all the certs are
		// signer certs.
		int i = 0;
		int count = 0;
		while (i < certs.length) {
		    count++;
		    while (((i+1) < certs.length) &&
			   ((X509Certificate)certs[i]).getIssuerDN().equals(
		               ((X509Certificate)certs[i+1]).getSubjectDN())) {
			i++;
		    }
		    i++;
		}
		if (count == certs.length) {
		    // All the certs are signer certs, so we store the entire
		    // array
		    this.certs =
			(java.security.cert.Certificate[])certs.clone();
		}

		if (this.certs == null) {
		    // extract the signer certs
		    ArrayList signerCerts = new ArrayList();
		    i = 0;
		    while (i < certs.length) {
			signerCerts.add(certs[i]);
			while (((i+1) < certs.length) &&
			    ((X509Certificate)certs[i]).getIssuerDN().equals(
             		      ((X509Certificate)certs[i+1]).getSubjectDN())) {
			    i++;
			}
			i++;
		    }
		    this.certs =
			new java.security.cert.Certificate[signerCerts.size()];
		    signerCerts.toArray(this.certs);
		}
	    }
	}
Methods Summary
public booleanequals(java.lang.Object obj)
Checks two UnresolvedPermission objects for equality. Checks that obj is an UnresolvedPermission, and has the same type (class) name, permission name, actions, and certificates as this object.

To determine certificate equality, this method only compares actual signer certificates. Supporting certificate chains are not taken into consideration by this method.

param
obj the object we are testing for equality with this object.
return
true if obj is an UnresolvedPermission, and has the same type (class) name, permission name, actions, and certificates as this object.

	if (obj == this)
	    return true;

	if (! (obj instanceof UnresolvedPermission))
	    return false;
	UnresolvedPermission that = (UnresolvedPermission) obj;

	// check type
	if (!this.type.equals(that.type)) {
	    return false;
	}

	// check name
	if (this.name == null) {
	    if (that.name != null) {
		return false;
	    }
	} else if (!this.name.equals(that.name)) {
	    return false;
	}

	// check actions
	if (this.actions == null) {
	    if (that.actions != null) {
		return false;
	    }
	} else {
	    if (!this.actions.equals(that.actions)) {
		return false;
	    }
	}

	// check certs
	if ((this.certs == null && that.certs != null) ||
	    (this.certs != null && that.certs == null) ||
	    (this.certs != null && that.certs != null &&
		this.certs.length != that.certs.length)) {
	    return false;
	}
	    
	int i,j;
	boolean match;

	for (i = 0; this.certs != null && i < this.certs.length; i++) {
	    match = false;
	    for (j = 0; j < that.certs.length; j++) {
		if (this.certs[i].equals(that.certs[j])) {
		    match = true;
		    break;
		}
	    }
	    if (!match) return false;
	}

	for (i = 0; that.certs != null && i < that.certs.length; i++) {
	    match = false;
	    for (j = 0; j < this.certs.length; j++) {
		if (that.certs[i].equals(this.certs[j])) {
		    match = true;
		    break;
		}
	    }
	    if (!match) return false;
	}
	return true;
public java.lang.StringgetActions()
Returns the canonical string representation of the actions, which currently is the empty string "", since there are no actions for an UnresolvedPermission. That is, the actions for the permission that will be created when this UnresolvedPermission is resolved may be non-null, but an UnresolvedPermission itself is never considered to have any actions.

return
the empty string "".

	return "";
public java.lang.StringgetUnresolvedActions()
Get the actions for the underlying permission that has not been resolved.

return
the actions for the underlying permission that has not been resolved, or null if there are no actions
since
1.5

	return actions;
public java.security.cert.Certificate[]getUnresolvedCerts()
Get the signer certificates (without any supporting chain) for the underlying permission that has not been resolved.

return
the signer certificates for the underlying permission that has not been resolved, or null, if there are no signer certificates. Returns a new array each time this method is called.
since
1.5

        return (certs == null) ? null :
                 (java.security.cert.Certificate[])certs.clone();
public java.lang.StringgetUnresolvedName()
Get the target name of the underlying permission that has not been resolved.

return
the target name of the underlying permission that has not been resolved, or null, if there is no targe name
since
1.5

	return name;
public java.lang.StringgetUnresolvedType()
Get the type (class name) of the underlying permission that has not been resolved.

return
the type (class name) of the underlying permission that has not been resolved
since
1.5

	return type;
public inthashCode()
Returns the hash code value for this object.

return
a hash code value for this object.

	int hash = type.hashCode();
	if (name != null)
	    hash ^= name.hashCode();
	if (actions != null)
	    hash ^= actions.hashCode();
	return hash;
public booleanimplies(java.security.Permission p)
This method always returns false for unresolved permissions. That is, an UnresolvedPermission is never considered to imply another permission.

param
p the permission to check against.
return
false.

	return false;
public java.security.PermissionCollectionnewPermissionCollection()
Returns a new PermissionCollection object for storing UnresolvedPermission objects.

return
a new PermissionCollection object suitable for storing UnresolvedPermissions.

	return new UnresolvedPermissionCollection();
private voidreadObject(java.io.ObjectInputStream ois)
Restores this object from a stream (i.e., deserializes it).

	CertificateFactory cf;
	Hashtable cfs=null;

	ois.defaultReadObject();

	if (type == null) 
		throw new NullPointerException("type can't be null");

	// process any new-style certs in the stream (if present)
	int size = ois.readInt();
	if (size > 0) {
	    // we know of 3 different cert types: X.509, PGP, SDSI, which
	    // could all be present in the stream at the same time
	    cfs = new Hashtable(3);
	    this.certs = new java.security.cert.Certificate[size];
	}

	for (int i=0; i<size; i++) {
	    // read the certificate type, and instantiate a certificate
	    // factory of that type (reuse existing factory if possible)
	    String certType = ois.readUTF();
	    if (cfs.containsKey(certType)) {
		// reuse certificate factory
		cf = (CertificateFactory)cfs.get(certType);
	    } else {
		// create new certificate factory
		try {
		    cf = CertificateFactory.getInstance(certType);
		} catch (CertificateException ce) {
		    throw new ClassNotFoundException
			("Certificate factory for "+certType+" not found");
		}
		// store the certificate factory so we can reuse it later
		cfs.put(certType, cf);
	    }
	    // parse the certificate
	    byte[] encoded=null;
	    try {
		encoded = new byte[ois.readInt()];
	    } catch (OutOfMemoryError oome) {
		throw new IOException("Certificate too big");
	    }
	    ois.readFully(encoded);
	    ByteArrayInputStream bais = new ByteArrayInputStream(encoded);
	    try {
		this.certs[i] = cf.generateCertificate(bais);
	    } catch (CertificateException ce) {
		throw new IOException(ce.getMessage());
	    }
	    bais.close();
	}
java.security.Permissionresolve(java.security.Permission p, java.security.cert.Certificate[] certs)
try and resolve this permission using the class loader of the permission that was passed in.


                         
         
	if (this.certs != null) {
	    // if p wasn't signed, we don't have a match
	    if (certs == null) {
		return null;
	    }

	    // all certs in this.certs must be present in certs
	    boolean match;
	    for (int i = 0; i < this.certs.length; i++) {
		match = false;
		for (int j = 0; j < certs.length; j++) {
		    if (this.certs[i].equals(certs[j])) {
			match = true;
			break;
		    }
		}
		if (!match) return null;
	    }
	}
	try {
	    Class pc = p.getClass();
	    
	    if (name == null && actions == null) {
	        try {
	            Constructor c = pc.getConstructor(PARAMS0);
	    	    return (Permission)c.newInstance(new Object[] {});
		} catch (NoSuchMethodException ne) {
		    try {
		        Constructor c = pc.getConstructor(PARAMS1);
                        return (Permission) c.newInstance(
			      new Object[] { name});
		    } catch (NoSuchMethodException ne1) {
		        Constructor c = pc.getConstructor(PARAMS2);
        		return (Permission) c.newInstance(
			      new Object[] { name, actions });
		    }
		}
	    } else {
	        if (name != null && actions == null) {
	            try {
	                Constructor c = pc.getConstructor(PARAMS1);
                        return (Permission) c.newInstance(
			      new Object[] { name});
		    } catch (NoSuchMethodException ne) {
		        Constructor c = pc.getConstructor(PARAMS2);
        	        return (Permission) c.newInstance(
			      new Object[] { name, actions });
		    }
	        } else {
                    Constructor c = pc.getConstructor(PARAMS2);
                    return (Permission) c.newInstance(
		          new Object[] { name, actions });
	        }
	    }
	} catch (NoSuchMethodException nsme) {
	    if (debug != null ) {
		debug.println("NoSuchMethodException:\n  could not find " +
			"proper constructor for " + type);
		nsme.printStackTrace();
	    }
	    return null;
	} catch (Exception e) {
	    if (debug != null ) {
		debug.println("unable to instantiate " + name);
		e.printStackTrace();
	    }
	    return null;
	}
public java.lang.StringtoString()
Returns a string describing this UnresolvedPermission. The convention is to specify the class name, the permission name, and the actions, in the following format: '(unresolved "ClassName" "name" "actions")'.

return
information about this UnresolvedPermission.

	return "(unresolved " + type + " " + name + " " + actions + ")";
private voidwriteObject(java.io.ObjectOutputStream oos)
Writes this object out to a stream (i.e., serializes it).

serialData
An initial String denoting the type is followed by a String denoting the name is followed by a String denoting the actions is followed by an int indicating the number of certificates to follow (a value of "zero" denotes that there are no certificates associated with this object). Each certificate is written out starting with a String denoting the certificate type, followed by an int specifying the length of the certificate encoding, followed by the certificate encoding itself which is written out as an array of bytes.

	oos.defaultWriteObject();

	if (certs==null || certs.length==0) {
	    oos.writeInt(0);
	} else {
	    // write out the total number of certs
	    oos.writeInt(certs.length);
	    // write out each cert, including its type
	    for (int i=0; i < certs.length; i++) {
		java.security.cert.Certificate cert = certs[i];
		try {
		    oos.writeUTF(cert.getType());
		    byte[] encoded = cert.getEncoded();
		    oos.writeInt(encoded.length);
		    oos.write(encoded);
		} catch (CertificateEncodingException cee) {
		    throw new IOException(cee.getMessage());
		}
	    }
	}