com.oneops.controller.cms.ExpressionEvaluator.java Source code

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/*******************************************************************************
 *
 *   Copyright 2015 Walmart, Inc.
 *
 *   Licensed 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
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "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.
 *
 *******************************************************************************/
package com.oneops.controller.cms;

import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.Expression;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.ParseException;
import org.springframework.expression.spel.support.StandardEvaluationContext;

import com.oneops.cms.cm.domain.CmsCI;
import com.oneops.cms.cm.domain.CmsCIAttribute;
import com.oneops.cms.cm.ops.domain.CmsActionOrder;
import com.oneops.cms.dj.domain.CmsWorkOrder;
import com.oneops.cms.domain.CmsWorkOrderBase;
import com.oneops.cms.simple.domain.CmsCISimple;
import com.oneops.cms.simple.domain.CmsRfcCISimple;
import com.oneops.cms.util.CmsConstants;
import com.oneops.cms.util.CmsUtil;

/**
 * This class is used to evaluate expression filter. The expression to be evaluated should follow 
 * the <a href="http://docs.spring.io/spring/docs/current/spring-framework-reference/html/expressions.html">SPEL</a> (Spring Expression Language) syntax.
 *
 * <p> The expression is evaluated against {@link com.oneops.cms.dj.domain.CmsRfcCI CmsRfcCI} for work orders and 
 * {@link com.oneops.cms.cm.domain.CmsCI CmsCI} for action orders.
 *
 * <p> Example:
 * <pre>ciClassName matches 'bom(\\..*\\.[0-9]+)?\\.Compute' and ciAttributes['size'] == 'M'</pre>
 *
 */
public class ExpressionEvaluator {

    private Logger logger = Logger.getLogger(this.getClass());
    private ExpressionParser exprParser;
    private CmsUtil cmsUtil;

    public static final String ATTR_NAME_FILTER = "filter";

    public boolean isExpressionMatching(CmsCI complianceCi, CmsWorkOrderBase wo) {

        CmsCIAttribute attr = complianceCi.getAttribute(ATTR_NAME_FILTER);
        if (attr == null) {
            return false;
        }
        String filter = attr.getDjValue();

        try {
            if (StringUtils.isNotBlank(filter)) {
                Expression expr = exprParser.parseExpression(filter);
                EvaluationContext context = getEvaluationContext(wo);
                //parse the filter expression and check if it matches this ci/rfc
                Boolean match = expr.getValue(context, Boolean.class);
                if (logger.isDebugEnabled()) {
                    logger.debug("Expression " + filter + " provided by compliance ci " + complianceCi.getCiId()
                            + " not matched for ci " + getCiName(wo));
                }

                return match;
            }
        } catch (ParseException | EvaluationException e) {
            String error = "Error in evaluating expression " + filter + " provided by compliance ci "
                    + complianceCi.getCiId() + ", target ci :" + getCiName(wo);
            logger.error(error, e);
        }
        return false;
    }

    private EvaluationContext getEvaluationContext(CmsWorkOrderBase woBase) {
        StandardEvaluationContext context = new StandardEvaluationContext();
        if (woBase instanceof CmsWorkOrder) {
            CmsRfcCISimple rfcSimple = cmsUtil.custRfcCI2RfcCISimple(((CmsWorkOrder) woBase).getRfcCi());
            context.setRootObject(rfcSimple);
        } else if (woBase instanceof CmsActionOrder) {
            CmsCISimple ciSimple = cmsUtil.custCI2CISimple(((CmsActionOrder) woBase).getCi(),
                    CmsConstants.ATTR_VALUE_TYPE_DF, true);
            context.setRootObject(ciSimple);
        }
        return context;
    }

    private String getCiName(CmsWorkOrderBase woBase) {
        String ciName = null;
        if (woBase instanceof CmsWorkOrder) {
            ciName = ((CmsWorkOrder) woBase).getRfcCi().getCiName();
        } else if (woBase instanceof CmsActionOrder) {
            ciName = ((CmsActionOrder) woBase).getCi().getCiName();
        }
        return ciName;
    }

    public void setExprParser(ExpressionParser exprParser) {
        this.exprParser = exprParser;
    }

    public void setCmsUtil(CmsUtil cmsUtil) {
        this.cmsUtil = cmsUtil;
    }

}