/*
* @(#)StaticRefPolicyFinderModule.java
*
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package com.sun.xacml.support.finder;
import java.io.File;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URL;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.sun.xacml.AbstractPolicy;
import com.sun.xacml.ParsingException;
import com.sun.xacml.PolicyMetaData;
import com.sun.xacml.VersionConstraints;
import com.sun.xacml.finder.PolicyFinder;
import com.sun.xacml.finder.PolicyFinderModule;
import com.sun.xacml.finder.PolicyFinderResult;
/**
* This is a simple implementation of <code>PolicyFinderModule</code> that supports retrieval based
* on reference, and is designed for use with a run-time configuration. Its constructor accepts a
* <code>List</code> of <code>String</code>s that represent URLs or files, and these are resolved to
* policies when the module is initialized. Beyond this, there is no modifying or re-loading the
* policies represented by this class. The policy's identifiers are used for reference resolution.
* <p>
* Note that this class is designed to complement <code>StaticPolicyFinderModule</code>. It would be
* easy to support both kinds of policy retrieval in a single class, but the functionality is
* instead split between two classes. The reason is that when you define a configuration for your
* PDP, it's easier to specify the two sets of policies by using two different finder modules.
* Typically, there aren't many policies that exist in both sets, so loading the sets separately
* isn't a problem. If this is a concern to you, simply create your own class and merge the two
* existing classes.
* <p>
* This module is provided as an example, but is still fully functional, and should be useful for
* many simple applications. This is provided in the <code>support</code> package rather than the
* core codebase because it implements non-standard behavior.
*
* @since 2.0
* @author Seth Proctor
*/
public class StaticRefPolicyFinderModule extends PolicyFinderModule {
// the list of policy URLs passed to the constructor
private List<String> policyList;
// the map of policies
private PolicyCollection policies;
// the optional schema file
private File schemaFile = null;
// the logger we'll use for all messages
private static final Logger logger = Logger.getLogger(StaticRefPolicyFinderModule.class
.getName());
/**
* Creates a <code>StaticRefPolicyFinderModule</code> that provides access to the given
* collection of policies. Any policy that cannot be loaded will be noted in the log, but will
* not cause an error. The schema file used to validate policies is defined by the property
* <code>PolicyReader.POLICY_SCHEMA_PROPERTY</code>. If the retrieved property is null, then no
* schema validation will occur.
*
* @param policyList
* a <code>List</code> of <code>String</code>s that represent URLs or files pointing
* to XACML policies
*/
public StaticRefPolicyFinderModule(List<String> policyList) {
this.policyList = policyList;
this.policies = new PolicyCollection();
String schemaName = System.getProperty(PolicyReader.POLICY_SCHEMA_PROPERTY);
if (schemaName != null)
schemaFile = new File(schemaName);
}
/**
* Creates a <code>StaticRefPolicyFinderModule</code> that provides access to the given
* collection of policyList.
*
* @param policyList
* a <code>List</code> of <code>String</code>s that represent URLs or files pointing
* to XACML policies
* @param schemaFile
* the schema file to validate policies against, or null if schema validation is not
* desired
*/
public StaticRefPolicyFinderModule(List<String> policyList, String schemaFile) {
this.policyList = policyList;
this.policies = new PolicyCollection();
if (schemaFile != null)
this.schemaFile = new File(schemaFile);
}
/**
* Always returns <code>true</code> since this module does support finding policies based on
* reference.
*
* @return true
*/
public boolean isIdReferenceSupported() {
return true;
}
/**
* Initialize this module. Typically this is called by <code>PolicyFinder</code> when a PDP is
* created. This method is where the policies are actually loaded.
*
* @param finder
* the <code>PolicyFinder</code> using this module
*/
public void init(PolicyFinder finder) {
// now that we have the PolicyFinder, we can load the policies
PolicyReader reader = new PolicyReader(finder, logger, schemaFile);
for (String str : policyList) {
AbstractPolicy policy = null;
try {
try {
// first try to load it as a URL
URL url = new URL(str);
policy = reader.readPolicy(url);
} catch (MalformedURLException murle) {
// assume that this is a filename, and try again
policy = reader.readPolicy(new File(str));
}
// we loaded the policy, so try putting it in the collection
if (!policies.addPolicy(policy))
if (logger.isLoggable(Level.WARNING))
logger.log(Level.WARNING, "tried to load the same "
+ "policy multiple times: " + str);
} catch (ParsingException pe) {
if (logger.isLoggable(Level.WARNING))
logger.log(Level.WARNING, "Error reading policy: " + str, pe);
}
}
}
/**
* Attempts to find a policy by reference, based on the provided parameters.
*
* @param idReference
* an identifier specifying some policy
* @param type
* type of reference (policy or policySet) as identified by the fields in
* <code>PolicyReference</code>
* @param constraints
* any optional constraints on the version of the referenced policy (this will never
* be null, but it may impose no constraints, and in fact will never impose
* constraints when used from a pre-2.0 XACML policy)
* @param parentMetaData
* the meta-data from the parent policy, which provides XACML version, factories,
* etc.
*
* @return the result of looking for a matching policy
*/
public PolicyFinderResult findPolicy(URI idReference, int type, VersionConstraints constraints,
PolicyMetaData parentMetaData) {
AbstractPolicy policy = policies.getPolicy(idReference.toString(), type, constraints);
if (policy == null)
return new PolicyFinderResult();
else
return new PolicyFinderResult(policy);
}
}