* This class uses a provider-based architecture, as described in the Java
* Cryptography Architecture. To create a CertPathBuilder, call
* one of the static getInstance methods, passing in the
* algorithm name of the CertPathBuilder desired and optionally
* the name of the provider desired.
*
* Once a CertPathBuilder object has been created, certification
* paths can be constructed by calling the {@link #build build} method and
* passing it an algorithm-specific set of parameters. If successful, the
* result (including the CertPath that was built) is returned
* in an object that implements the CertPathBuilderResult
* interface.
*
* Concurrent Access *
* The static methods of this class are guaranteed to be thread-safe. * Multiple threads may concurrently invoke the static methods defined in * this class with no ill effects. *
* However, this is not true for the non-static methods defined by this class.
* Unless otherwise documented by a specific provider, threads that need to
* access a single CertPathBuilder instance concurrently should
* synchronize amongst themselves and provide the necessary locking. Multiple
* threads each manipulating a different CertPathBuilder instance
* need not synchronize.
*
* @see CertPath
*
* @version 1.9 06/28/04
* @since 1.4
* @author Sean Mullan
* @author Yassir Elley
*/
public class CertPathBuilder {
/*
* Constant to lookup in the Security properties file to determine
* the default certpathbuilder type. In the Security properties file,
* the default certpathbuilder type is given as:
*
* certpathbuilder.type=PKIX
*
*/
private static final String CPB_TYPE = "certpathbuilder.type";
private static final Debug debug = Debug.getInstance("certpath");
private CertPathBuilderSpi builderSpi;
private Provider provider;
private String algorithm;
/**
* Creates a CertPathBuilder object of the given algorithm,
* and encapsulates the given provider implementation (SPI object) in it.
*
* @param builderSpi the provider implementation
* @param provider the provider
* @param algorithm the algorithm name
*/
protected CertPathBuilder(CertPathBuilderSpi builderSpi, Provider provider,
String algorithm)
{
this.builderSpi = builderSpi;
this.provider = provider;
this.algorithm = algorithm;
}
/**
* Returns a CertPathBuilder object that implements the
* specified algorithm.
*
* If the default provider package provides an implementation of the
* specified CertPathBuilder algorithm, an instance of
* CertPathBuilder containing that implementation is returned.
* If the requested algorithm is not available in the default package,
* other packages are searched.
*
* @param algorithm the name of the requested CertPathBuilder
* algorithm
* @return a CertPathBuilder object that implements the
* specified algorithm
* @throws NoSuchAlgorithmException if the requested algorithm is
* not available in the default provider package or any of the other
* provider packages that were searched
*/
public static CertPathBuilder getInstance(String algorithm)
throws NoSuchAlgorithmException {
Instance instance = GetInstance.getInstance("CertPathBuilder",
CertPathBuilderSpi.class, algorithm);
return new CertPathBuilder((CertPathBuilderSpi)instance.impl,
instance.provider, algorithm);
}
/**
* Returns a CertPathBuilder object that implements the
* specified algorithm, as supplied by the specified provider.
*
* @param algorithm the name of the requested CertPathBuilder
* algorithm
* @param provider the name of the provider
* @return a CertPathBuilder object that implements the
* specified algorithm, as supplied by the specified provider
* @throws NoSuchAlgorithmException if the requested algorithm is
* not available from the specified provider
* @throws NoSuchProviderException if the provider has not been configured
* @exception IllegalArgumentException if the provider is
* null
*/
public static CertPathBuilder getInstance(String algorithm, String provider)
throws NoSuchAlgorithmException, NoSuchProviderException {
Instance instance = GetInstance.getInstance("CertPathBuilder",
CertPathBuilderSpi.class, algorithm, provider);
return new CertPathBuilder((CertPathBuilderSpi)instance.impl,
instance.provider, algorithm);
}
/**
* Returns a CertPathBuilder object that implements the
* specified algorithm, as supplied by the specified provider.
* Note: the provider doesn't have to be registered.
*
* @param algorithm the name of the requested CertPathBuilder
* algorithm
* @param provider the provider
* @return a CertPathBuilder object that implements the
* specified algorithm, as supplied by the specified provider
* @exception NoSuchAlgorithmException if the requested algorithm is
* not available from the specified provider
* @exception IllegalArgumentException if the provider is
* null.
*/
public static CertPathBuilder getInstance(String algorithm,
Provider provider) throws NoSuchAlgorithmException {
Instance instance = GetInstance.getInstance("CertPathBuilder",
CertPathBuilderSpi.class, algorithm, provider);
return new CertPathBuilder((CertPathBuilderSpi)instance.impl,
instance.provider, algorithm);
}
/**
* Returns the provider of this CertPathBuilder.
*
* @return the provider of this CertPathBuilder
*/
public final Provider getProvider() {
return this.provider;
}
/**
* Returns the name of the algorithm of this CertPathBuilder.
*
* @return the name of the algorithm of this CertPathBuilder
*/
public final String getAlgorithm() {
return this.algorithm;
}
/**
* Attempts to build a certification path using the specified algorithm
* parameter set.
*
* @param params the algorithm parameters
* @return the result of the build algorithm
* @throws CertPathBuilderException if the builder is unable to construct
* a certification path that satisfies the specified parameters
* @throws InvalidAlgorithmParameterException if the specified parameters
* are inappropriate for this CertPathBuilder
*/
public final CertPathBuilderResult build(CertPathParameters params)
throws CertPathBuilderException, InvalidAlgorithmParameterException
{
return builderSpi.engineBuild(params);
}
/**
* Returns the default CertPathBuilder type as specified in
* the Java security properties file, or the string "PKIX"
* if no such property exists. The Java security properties file is
* located in the file named <JAVA_HOME>/lib/security/java.security,
* where <JAVA_HOME> refers to the directory where the JDK was
* installed.
*
*
The default CertPathBuilder type can be used by
* applications that do not want to use a hard-coded type when calling one
* of the getInstance methods, and want to provide a default
* type in case a user does not specify its own.
*
*
The default CertPathBuilder type can be changed by
* setting the value of the "certpathbuilder.type" security property
* (in the Java security properties file) to the desired type.
*
* @return the default CertPathBuilder type as specified
* in the Java security properties file, or the string "PKIX"
* if no such property exists.
*/
public final static String getDefaultType() {
String cpbtype;
cpbtype = (String)AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
return Security.getProperty(CPB_TYPE);
}
});
if (cpbtype == null) {
cpbtype = "PKIX";
}
return cpbtype;
}
}