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

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 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
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 *    http://www.apache.org/licenses/LICENSE-2.0
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 *          THIS FILE CONTAINS PROPRIETARY INFORMATION OF
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package org.apache.openaz.xacml.pdp.std.functions;

import java.util.ArrayList;
import java.util.List;

import org.apache.openaz.xacml.api.DataType;
import org.apache.openaz.xacml.api.Identifier;
import org.apache.openaz.xacml.api.Status;
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.StdStatusCode;
import org.apache.openaz.xacml.std.datatypes.DataTypes;

/**
 * FunctionDefinitionEquality extends
 * {@link org.apache.openaz.xacml.pdp.std.functions.FunctionDefinitionHomogeneousSimple} to implement the
 * XACML Equality predicates as functions taking two arguments of the same data type and returning a
 * <code>Boolean</code>. 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-equal boolean-equal integer-equal double-equal date-equal time-equal
 * dateTime-equal dayTimeDuration-equal yearMonthDuration-equal anyURI-equal
 *
 * @param <I> the java class for the data type of the function Input arguments
 */
public class FunctionDefinitionEquality<I> extends FunctionDefinitionHomogeneousSimple<Boolean, I> {

    /**
     * Determines if the two <code>T</code> values are equal using the java <code>equals</code> method.
     * Derived classes may override this if the <code>equals</code> method is not sufficient.
     *
     * @param v1 the first object to compare
     * @param v2 the second object to compare
     * @return true if the two objects are the same, else false
     */
    protected boolean isEqual(I v1, I v2) {
        return v1.equals(v2);
    }

    public FunctionDefinitionEquality(Identifier idIn, DataType<I> dataTypeArgsIn) {
        super(idIn, DataTypes.DT_BOOLEAN, dataTypeArgsIn, 2);
    }

    @Override
    public ExpressionResult evaluate(EvaluationContext evaluationContext, List<FunctionArgument> arguments) {
        List<I> convertedArguments = new ArrayList<I>();
        Status status = this.validateArguments(arguments, convertedArguments);

        /*
         * If the function arguments are not correct, just return an error status immediately
         */
        if (!status.getStatusCode().equals(StdStatusCode.STATUS_CODE_OK)) {
            return ExpressionResult.newError(getFunctionStatus(status));
        }

        /*
         * Now just perform the equality operation.
         */
        if (this.isEqual(convertedArguments.get(0), convertedArguments.get(1))) {
            return ER_TRUE;
        } else {
            return ER_FALSE;
        }
    }

}