openaz-xacml-pdp/src/main/java/org/apache/openaz/xacml/pdp/std/functions/FunctionDefinitionBagOneAndOnly.java

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 *  to you under the Apache License, Version 2.0 (the
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/*
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 *          THIS FILE CONTAINS PROPRIETARY INFORMATION OF
 *        AT&T AND IS NOT TO BE DISCLOSED OR USED EXCEPT IN
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package org.apache.openaz.xacml.pdp.std.functions;

import java.util.List;

import org.apache.openaz.xacml.api.AttributeValue;
import org.apache.openaz.xacml.api.DataType;
import org.apache.openaz.xacml.api.Identifier;
import org.apache.openaz.xacml.pdp.eval.EvaluationContext;
import org.apache.openaz.xacml.pdp.policy.Bag;
import org.apache.openaz.xacml.pdp.policy.ExpressionResult;
import org.apache.openaz.xacml.pdp.policy.FunctionArgument;
import org.apache.openaz.xacml.std.StdStatus;
import org.apache.openaz.xacml.std.StdStatusCode;

/**
 * FunctionDefinitionBagOneAndOnly implements {@link org.apache.openaz.xacml.pdp.policy.FunctionDefinition}
 * to implement the XACML 'type'-one-and-only predicates as functions taking one <code>Bag</code> argument and
 * returning the single element in that bag of the 'type'. In the first implementation of XACML we had
 * separate files for each XACML Function. This release combines multiple Functions in fewer files to minimize
 * code duplication. This file supports the following XACML codes: string-one-and-only boolean-one-and-only
 * integer-one-and-only double-one-and-only time-one-and-only date-one-and-only dateTime-one-and-only
 * anyURI-one-and-only hexBinary-one-and-only base64Binary-one-and-only dayTimeDuration-one-and-only (version
 * 1 and3) yearMonthDuration-one-and-only (version 1 and 3) x500Name-one-and-only rfc822Name-one-and-only
 * ipAddress-one-and-only dnsName-one-and-only
 *
 * @param <I> the java class for the data type of the elements in the bag handed to this as the Input argument,
 *            which is also the type of the return value
 */
public class FunctionDefinitionBagOneAndOnly<I> extends FunctionDefinitionBase<I, I> {

    /**
     * Constructor - need dataType input because of java Generic type-erasure during compilation.
     *
     * @param idIn
     * @param dataTypeArgsIn
     */
    public FunctionDefinitionBagOneAndOnly(Identifier idIn, DataType<I> dataTypeArgsIn) {
        super(idIn, dataTypeArgsIn, dataTypeArgsIn, false);
    }

    /**
     * Evaluates this <code>FunctionDefinition</code> on the given <code>List</code> of
     * {@link org.apache.openaz.xacml.pdp.policy.FunctionArgument}s.
     *
     * @param evaluationContext the {@link org.apache.openaz.xacml.pdp.eval.EvaluationContext} to use in the
     *            evaluation
     * @param arguments the <code>List</code> of <code>FunctionArgument</code>s for the evaluation
     * @return an {@link org.apache.openaz.xacml.pdp.policy.ExpressionResult} with the results of the call
     */
    @Override
    public ExpressionResult evaluate(EvaluationContext evaluationContext, List<FunctionArgument> arguments) {

        if (arguments == null || arguments.size() != 1) {
            return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR,
                                                           getShortFunctionId()
                                                               + " Expected 1 argument, got "
                                                               + ((arguments == null) ? "null" : arguments
                                                                   .size())));
        }

        FunctionArgument argument = arguments.get(0);
        ConvertedArgument<Bag> convertedArgument = new ConvertedArgument<Bag>(argument, null, true);

        if (!convertedArgument.isOk()) {
            return ExpressionResult.newError(getFunctionStatus(convertedArgument.getStatus()));
        }

        Bag bag = convertedArgument.getBag();

        if (bag.size() != 1) {
            return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR,
                                                           getShortFunctionId() + " Expected 1 but Bag has "
                                                               + bag.size() + " elements"));
        }

        // get the single value from the bag
        AttributeValue<?> attributeValueOneAndOnly = bag.getAttributeValues().next();
        assert attributeValueOneAndOnly != null;

        // make sure it has the right type
        //
        if (!this.getDataTypeId().equals(attributeValueOneAndOnly.getDataTypeId())) {
            return ExpressionResult
                .newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR,
                                        getShortFunctionId()
                                            + " Element in bag of wrong type. Expected "
                                            + this.getShortDataTypeId(this.getDataTypeId())
                                            + " got "
                                            + this.getShortDataTypeId(attributeValueOneAndOnly
                                                .getDataTypeId())));
        }
        return ExpressionResult.newSingle(attributeValueOneAndOnly);
    }

}