org.jscience.util.license
Class License

java.lang.Object
  org.jscience.util.license.License

All Implemented Interfaces:

java.io.Serializable

public final class License
extends java.lang.Object
implements java.io.Serializable

a License provides and limits access to certain functionality based on individual classes or packages. Note that for a License to be accepted by the LicenseManager, the License must be properly signed. A method for properly signing a License is not available under GPL, but there are License objects freely available on request.

See Also:

LicenseManager, LicensingException, Serialized Form

Field Summary

static int

INDEFINATE DOCUMENT ME!

Constructor Summary

License(java.lang.Class licenseeClass, java.lang.String issuedFor, java.util.Date expirationDate, int usageLimit)
only usable if properly signed

License(java.lang.Package licenseePackage, java.lang.String issuedFor, java.util.Date expirationDate, int usageLimit)
only usable if properly signed

License(java.lang.String classOrPackageName, java.lang.String issuedFor, java.util.Date expirationDate, int usageLimit)
only usable if properly signed

Method Summary

void	addBoundEnvironment(java.lang.String envVariable, java.lang.String value) allows to add a condition where this license can only be used if the given environment variable corresponds to the given value.
void	addBoundProperty(java.lang.String key, java.lang.String value) allows to add a condition where this license can only be used in an environment where the given system property corresponds to the given value.
void	checkValidation() checks whether this license is properly singed, not expired and still has usage left.
java.util.Map<java.lang.String,java.lang.String>	getBoundEnvironment() returns an unmodifiable view of the bound environment variables of this license
java.util.Map<java.lang.String,java.lang.String>	getBoundProperties() returns an unmodifiable view of the bound system properties of this license
java.util.Date	getCreationDate() returns the time when this license was created.
java.lang.Object	getLicensee() returns either a Class or a String representing the Package
byte[]	getSignature() returns a copy of the signature that is used to verify that this license has been created by an authorized issuer
java.lang.String	issuedFor() a hint to whom this license was issued
boolean	isValid() returns true only if this license passes checkValidation().
static License	loadLicense(byte[] bytes) deserializes a license object from a byte pattern
static License	loadLicense(java.io.File file) loads a serialized license from a file
static License	loadLicense(java.io.InputStream stream) loads a serialized license from a stream
void	saveTo(java.io.File file) convenience method; overwrites the file if it exists
void	setSignature(byte[] signature) the method that signes the license and thus makes it usable
java.lang.String	toString() includes only a subset of restrictions for this license
int	usageLeft() returns how many times use() can be called. if INDEFINATE is returned, this license is not limited by usage.
int	use() uses this license; if usage is limited, the return value of usageLeft() is decreased by one after a call to this method.
java.util.Date	validUntil() returns the date after which this license expires.
byte[]	verification() returns the data that serves as a basis for generating the signature.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

INDEFINATE

public static final int INDEFINATE

DOCUMENT ME!

See Also:

Constant Field Values

Constructor Detail

License

public License(java.lang.Package licenseePackage,
               java.lang.String issuedFor,
               java.util.Date expirationDate,
               int usageLimit)

only usable if properly signed

License

public License(java.lang.Class licenseeClass,
               java.lang.String issuedFor,
               java.util.Date expirationDate,
               int usageLimit)

only usable if properly signed

License

public License(java.lang.String classOrPackageName,
               java.lang.String issuedFor,
               java.util.Date expirationDate,
               int usageLimit)

only usable if properly signed

Method Detail

verification

public byte[] verification()

returns the data that serves as a basis for generating the signature.

Returns:

DOCUMENT ME!

Throws:

java.lang.RuntimeException - DOCUMENT ME!

addBoundEnvironment

public void addBoundEnvironment(java.lang.String envVariable,
                                java.lang.String value)
                         throws java.lang.IllegalStateException

allows to add a condition where this license can only be used if the given environment variable corresponds to the given value. Bound values can only be changed before a license was signed.

Parameters:

envVariable - DOCUMENT ME!

value - DOCUMENT ME!

Throws:

java.lang.IllegalStateException - if the license has already been signed

java.lang.NullPointerException - DOCUMENT ME!

addBoundProperty

public void addBoundProperty(java.lang.String key,
                             java.lang.String value)
                      throws java.lang.IllegalStateException

allows to add a condition where this license can only be used in an environment where the given system property corresponds to the given value. Bound values can only be changed before a license was signed.

Parameters:

key - DOCUMENT ME!

value - DOCUMENT ME!

Throws:

java.lang.IllegalStateException - if the license has already been signed

java.lang.NullPointerException - DOCUMENT ME!

getBoundProperties

public java.util.Map<java.lang.String,java.lang.String> getBoundProperties()

returns an unmodifiable view of the bound system properties of this license

Returns:

DOCUMENT ME!

getBoundEnvironment

public java.util.Map<java.lang.String,java.lang.String> getBoundEnvironment()

returns an unmodifiable view of the bound environment variables of this license

Returns:

DOCUMENT ME!

getCreationDate

public java.util.Date getCreationDate()

returns the time when this license was created.

Returns:

DOCUMENT ME!

issuedFor

public java.lang.String issuedFor()

a hint to whom this license was issued

Returns:

DOCUMENT ME!

getSignature

public byte[] getSignature()

returns a copy of the signature that is used to verify that this license has been created by an authorized issuer

Returns:

DOCUMENT ME!

setSignature

public void setSignature(byte[] signature)
                  throws LicensingException

the method that signes the license and thus makes it usable

Parameters:

signature - DOCUMENT ME!

Throws:

LicensingException - if the signature is invalid

java.lang.IllegalStateException - if the license has already been signed

saveTo

public void saveTo(java.io.File file)
            throws java.io.IOException

convenience method; overwrites the file if it exists

Throws:

java.io.IOException

See Also:

loadLicense(File)

loadLicense

public static License loadLicense(java.io.File file)
                           throws java.io.IOException,
                                  LicensingException

loads a serialized license from a file

Throws:

java.io.IOException

LicensingException

See Also:

saveTo(File)

loadLicense

public static License loadLicense(java.io.InputStream stream)
                           throws java.io.IOException,
                                  LicensingException

loads a serialized license from a stream

Throws:

java.io.IOException

LicensingException

See Also:

saveTo(File)

loadLicense

public static License loadLicense(byte[] bytes)
                           throws java.io.IOException,
                                  LicensingException

deserializes a license object from a byte pattern

Throws:

java.io.IOException

LicensingException

See Also:

IOUtils.serialize(Object)

getLicensee

public java.lang.Object getLicensee()

returns either a Class or a String representing the Package

Returns:

DOCUMENT ME!

isValid

public boolean isValid()

returns true only if this license passes checkValidation(). If you require more detail, call checkValidation() directly.

See Also:

checkValidation()

checkValidation

public void checkValidation()
                     throws LicensingException

checks whether this license is properly singed, not expired and still has usage left. The license itself is not altered through this call.

Throws:

LicensingException

See Also:

use(), LicenseManager.verifyLicense(License)

validUntil

public java.util.Date validUntil()

returns the date after which this license expires. If the return value is null, this license doesn't expire in time.

Returns:

DOCUMENT ME!

usageLeft

public int usageLeft()

returns how many times use() can be called. if INDEFINATE is returned, this license is not limited by usage.

See Also:

use()

use

public int use()
        throws LicensingException

uses this license; if usage is limited, the return value of usageLeft() is decreased by one after a call to this method.

Throws:

LicensingException

See Also:

isValid()

toString

public java.lang.String toString()

includes only a subset of restrictions for this license

Overrides:

toString in class java.lang.Object

Returns:

DOCUMENT ME!