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

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 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
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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
 *  with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
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 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License.
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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
 *             ACCORDANCE WITH APPLICABLE AGREEMENTS.
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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.DataTypes;

/**
 * FunctionDefinitionRegexMatch implements {@link org.apache.openaz.xacml.pdp.policy.FunctionDefinition} to
 * implement the XACML 'type'-regex-match predicates as functions taking two arguments, the first of
 * <code>String</code>, representing a regular expression, and the second of the type for that specific
 * predicate, and returning a <code>Boolean</code> for whether the regular expression matches the string
 * representation of the second argument. 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-regexp-match anyURI-regexp-match x500Name-regexp-match
 * rfc822Name-regexp-match (in sub-class
 * {@link org.apache.openaz.xacml.pdp.policy.FunctionDefinition.FunctionDefinitionRegexpMatchRFC822} )
 * ipAddress-regexp-match dnsName-regexp-match
 *
 * @param <I> the java class for the data type of the function Input arguments
 */
public class FunctionDefinitionRegexpMatch<I> extends FunctionDefinitionBase<Boolean, I> {

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

    @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())));
        }

        // get the regular expression
        FunctionArgument regexpArgument = arguments.get(0);

        ConvertedArgument<String> convertedArgument = new ConvertedArgument<String>(regexpArgument,
                                                                                    DataTypes.DT_STRING,
                                                                                    false);
        if (!convertedArgument.isOk()) {
            return ExpressionResult.newError(getFunctionStatus(convertedArgument.getStatus()));
        }

        // String regexpValue = (String)regexpArgument.getValue().getValue();
        String regexpValue = convertedArgument.getValue();

        // now get the element to match
        FunctionArgument elementArgument = arguments.get(1);

        ConvertedArgument<I> convertedElement = new ConvertedArgument<I>(elementArgument,
                                                                         this.getDataTypeArgs(), false);
        if (!convertedElement.isOk()) {
            return ExpressionResult.newError(getFunctionStatus(convertedElement.getStatus()));
        }

        I elementValueObject = convertedElement.getValue();

        String elementValueString;
        try {
            elementValueString = this.getDataTypeArgs().toStringValue(elementValueObject);
        } 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));
        }

        // ConvertedArgument checks for null value, so do not need to do again here

        if (elementValueString.matches(regexpValue)) {
            return ER_TRUE;
        } else {
            return ER_FALSE;
        }

    }

}