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ATT reference implementation of XACML PDP engine
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/*
*
* Copyright (c) 2013,2019 AT&T Knowledge Ventures
* SPDX-License-Identifier: MIT
*/
package com.att.research.xacmlatt.pdp.std.functions;
import com.att.research.xacml.api.AttributeValue;
import com.att.research.xacml.api.DataType;
import com.att.research.xacml.api.Identifier;
import com.att.research.xacml.api.Status;
import com.att.research.xacml.std.StdStatus;
import com.att.research.xacml.std.StdStatusCode;
import com.att.research.xacmlatt.pdp.policy.Bag;
import com.att.research.xacmlatt.pdp.policy.FunctionArgument;
/**
* A ConvertedArgument is the result of processing an {@link com.att.research.xacmlatt.pdp.policy.FunctionArgument}
* to validate its correctness and to convert it into an object of the required type.
* It is returned by the validateArguments method in
* {@link com.att.research.xacmlatt.pdp.std.functions.FunctionDefinitionHomogeneousSimple}
* and should only be used by other Functions in that same package.
* This is a data holder with no processing.
* It contains two elements:
*
* -
* A {@link com.att.research.xacml.api.Status} object, and
*
-
* An object containing the value of the FunctionArgument processed by validateArguments.
* This object will only exist if status.isOk() (or the isOk() method in this class that calls status.isOk()) is true.
*
*
*
* @author glenngriffin
*
*/
public class ConvertedArgument {
// When status != Status.OK, the value is null
private Status status;
// This is non-null when status == Status.OK
private I value = null;
/**
* Constructor ensures we have a non-null status, though value will be null if status is not ok.
*
* @param s Status
* @param v Converted argument object
*/
public ConvertedArgument(Status s, I v) {
status = s;
if (s == null) {
throw new IllegalArgumentException("Status of argument cannot be null");
}
if (s.isOk()) {
// only set value if status is ok
value = v;
}
}
/**
* Get the Status object
*
* @return Status object
*/
public Status getStatus() {
return status;
}
/**
* Convenience method that directly returns the isOk() state from the status object.
*
* @return Status isOK state
*/
public boolean isOk() {
return status.isOk();
}
/**
* Get the value object. This may be a Bag.
*
* @return Value object - possibly a bag
*/
public I getValue() {
return value;
}
/**
* Get the value as a Bag. (convenience method)
*
* @return The value as a bag.
*/
public Bag getBag() {
return (Bag)value;
}
/**
* Returns a shortened version of the given DataType Id, primarily for use with error messages to prevent them from becoming too long.
* This is a simple convenience method to reduce code bloat.
*
* @param identifier expected to have '#' in it, and if no '#' should have ":data-type:"
* @return String Shortened version of DataType Id
*/
public String getShortDataTypeId(Identifier identifier) {
String idString = identifier.stringValue();
int index = idString.indexOf('#');
if (index < 0) {
index = idString.indexOf(":data-type:");
if (index < 0) {
return idString;
} else {
return idString.substring(index + 11);
}
} else {
return idString.substring(index+1);
}
}
/**
* Evaluates the given FunctionArgument and validates that it has the correct DataType.
* The returned object will be either:
*
* -
* A Status Object indicating an error condition, or
*
-
* An Object of the appropriate type containing the value of the function.
* In this case the caller should assume that the Status is Status.OK.
* Note that the object may be a bag if that is what the caller expected.
*
*
* @param functionArgument Given function argument
* @param expectedDataType The expected data type
* @param expectBag Whether to expect a bag
*/
@SuppressWarnings("unchecked") // to suppress warning on bag conversion
public ConvertedArgument(FunctionArgument functionArgument, DataType expectedDataType, boolean expectBag) {
if (functionArgument == null ) {
status = new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, "Got null argument");
return;
}
if ( ! functionArgument.isOk()) {
status = functionArgument.getStatus();
return;
}
// bags are valid arguments for some functions
if (expectBag) {
if ( ! functionArgument.isBag()) {
status = new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, "Expected a bag, saw a simple value");
return;
}
Bag bag = functionArgument.getBag();
value = (I) bag;
status = StdStatus.STATUS_OK;
return;
}
// argument should not be a bag
if (functionArgument.isBag()) {
status = new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, "Expected a simple value, saw a bag");
return;
}
AttributeValue attributeValue = functionArgument.getValue();
if (attributeValue == null || attributeValue.getValue() == null) {
status = new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, "Got null attribute");
return;
}
if ( ! attributeValue.getDataTypeId().equals(expectedDataType.getId())) {
status = new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, "Expected data type '" +
getShortDataTypeId(expectedDataType.getId()) + "' saw '" + getShortDataTypeId(attributeValue.getDataTypeId()) + "'");
return;
}
try {
value = expectedDataType.convert(attributeValue.getValue());
status = StdStatus.STATUS_OK;
} catch (Exception e) {
String message = e.getMessage();
if (e.getCause() != null) {
message = e.getCause().getMessage();
}
status = new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, message);
}
}
}