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

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 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
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 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
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/*
 *                        AT&T - PROPRIETARY
 *          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.DataType;
import org.apache.openaz.xacml.api.DataTypeException;
import org.apache.openaz.xacml.api.Identifier;
import org.apache.openaz.xacml.pdp.eval.EvaluationContext;
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;
import org.apache.openaz.xacml.std.datatypes.IDateTime;
import org.apache.openaz.xacml.std.datatypes.ISO8601Duration;

/**
 * FunctionDefinitionDateTimeArithmetic implements
 * {@link org.apache.openaz.xacml.pdp.policy.FunctionDefinition} to implement the XACML Date and Time
 * Arithmetic predicates. 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: dateTime-add-dayTimeDuration dateTime-add-yearMonthDuration
 * dateTime-subtract-dayTimeDuration dateTime-subtract-yearMonthDuration date-add-yearMonthDuration
 * date-subtract-yearMonthDuration
 *
 * @param <I> the java class for the data type of the function Input arguments; SPECIAL CASE: this applies ONLY
 *            to the 2nd argument.
 * @param <O> the java class for the data type of the function Output; SPECIAL CASE: this ALSO applies to the
 *            type of the 1st Input argument.
 */
public class FunctionDefinitionDateTimeArithmetic<O extends IDateTime<O>, I extends ISO8601Duration> extends
    FunctionDefinitionBase<O, I> {

    /**
     * List of Date and Time Arithmetic operations.
     */
    public enum OPERATION {
        ADD,
        SUBTRACT
    };

    // operation to be used in this instance of the class
    private final OPERATION operation;

    /**
     * Constructor - need dataTypeArgs input because of java Generic type-erasure during compilation.
     *
     * @param idIn
     * @param dataTypeArgsIn
     */
    public FunctionDefinitionDateTimeArithmetic(Identifier idIn, DataType<O> dataTypeIn,
                                                DataType<I> dataTypeArgsIn, OPERATION op) {
        super(idIn, dataTypeIn, dataTypeArgsIn, false);
        this.operation = op;
    }

    @Override
    public ExpressionResult evaluate(EvaluationContext evaluationContext, List<FunctionArgument> arguments) {
        if (arguments == null || arguments.size() != 2) {
            return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR,
                                                           this.getShortFunctionId()
                                                               + " Expected 2 arguments, got "
                                                               + ((arguments == null) ? "null" : arguments
                                                                   .size())));
        }

        // first arg has same type as function output
        FunctionArgument functionArgument = arguments.get(0);
        ConvertedArgument<O> convertedArgument0 = new ConvertedArgument<O>(functionArgument,
                                                                           this.getDataType(), false);
        if (!convertedArgument0.isOk()) {
            return ExpressionResult.newError(getFunctionStatus(convertedArgument0.getStatus()));
        }
        O idateOrig = convertedArgument0.getValue();

        // second argument is of input type
        functionArgument = arguments.get(1);
        ConvertedArgument<I> convertedArgument1 = new ConvertedArgument<I>(functionArgument,
                                                                           this.getDataTypeArgs(), false);
        if (!convertedArgument1.isOk()) {
            return ExpressionResult.newError(getFunctionStatus(convertedArgument1.getStatus()));
        }
        // get the Duration object from the argument which includes all fields, even if the incoming argument
        // does not include them all
        ISO8601Duration duration = convertedArgument1.getValue();

        // add/subtract the duration to the input argument
        //
        O idateResult = null;
        switch (this.operation) {
        case ADD:
            idateResult = idateOrig.add(duration);
            break;
        case SUBTRACT:
            idateResult = idateOrig.sub(duration);
            break;
        }
        ExpressionResult expressionResult = null;
        try {
            expressionResult = ExpressionResult.newSingle(this.getDataType()
                .createAttributeValue(idateResult));
        } catch (DataTypeException e) {
            String message = e.getMessage();
            if (e.getCause() != null) {
                message = e.getCause().getMessage();
            }
            return ExpressionResult.newError(new StdStatus(StdStatusCode.STATUS_CODE_PROCESSING_ERROR, this
                .getShortFunctionId() + " " + message));
        }
        return expressionResult;
    }

}