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Complex event processing and event series analysis component
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/*
 ***************************************************************************************
 *  Copyright (C) 2006 EsperTech, Inc. All rights reserved.                            *
 *  http://www.espertech.com/esper                                                     *
 *  http://www.espertech.com                                                           *
 *  ---------------------------------------------------------------------------------- *
 *  The software in this package is published under the terms of the GPL license       *
 *  a copy of which has been included with this distribution in the license.txt file.  *
 ***************************************************************************************
 */
package com.espertech.esper.event.map;

import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.PropertyAccessException;
import com.espertech.esper.codegen.base.CodegenBlock;
import com.espertech.esper.codegen.base.CodegenClassScope;
import com.espertech.esper.codegen.base.CodegenMethodScope;
import com.espertech.esper.codegen.model.expression.CodegenExpression;
import com.espertech.esper.codegen.base.CodegenMethodNode;
import com.espertech.esper.event.BaseNestableEventUtil;
import com.espertech.esper.event.EventPropertyGetterSPI;

import java.util.Map;

import static com.espertech.esper.codegen.model.expression.CodegenExpressionBuilder.*;

/**
 * A getter that works on EventBean events residing within a Map as an event property.
 */
public class MapEventBeanEntryPropertyGetter implements MapEventPropertyGetter {

    private final String propertyMap;
    private final EventPropertyGetterSPI eventBeanEntryGetter;

    /**
     * Ctor.
     *  @param propertyMap          the property to look at
     * @param eventBeanEntryGetter the getter for the map entry
     */
    public MapEventBeanEntryPropertyGetter(String propertyMap, EventPropertyGetterSPI eventBeanEntryGetter) {
        this.propertyMap = propertyMap;
        this.eventBeanEntryGetter = eventBeanEntryGetter;
    }

    public Object getMap(Map map) throws PropertyAccessException {
        // If the map does not contain the key, this is allowed and represented as null
        Object value = map.get(propertyMap);

        if (value == null) {
            return null;
        }

        // Object within the map
        EventBean theEvent = (EventBean) value;
        return eventBeanEntryGetter.get(theEvent);
    }

    private CodegenMethodNode getMapCodegen(CodegenMethodScope codegenMethodScope, CodegenClassScope codegenClassScope) {
        CodegenBlock block = codegenMethodScope.makeChild(Object.class, this.getClass(), codegenClassScope).addParam(Map.class, "map").getBlock()
                .declareVar(Object.class, "value", exprDotMethod(ref("map"), "get", constant(propertyMap)))
                .ifRefNullReturnNull("value");
        return block.declareVar(EventBean.class, "theEvent", cast(EventBean.class, ref("value")))
                .methodReturn(eventBeanEntryGetter.eventBeanGetCodegen(ref("theEvent"), codegenMethodScope, codegenClassScope));
    }

    public boolean isMapExistsProperty(Map map) {
        return true; // Property exists as the property is not dynamic (unchecked)
    }

    public Object get(EventBean obj) {
        return getMap(BaseNestableEventUtil.checkedCastUnderlyingMap(obj));
    }

    public boolean isExistsProperty(EventBean eventBean) {
        return true; // Property exists as the property is not dynamic (unchecked)
    }

    public Object getFragment(EventBean obj) {
        Map map = BaseNestableEventUtil.checkedCastUnderlyingMap(obj);

        // If the map does not contain the key, this is allowed and represented as null
        Object value = map.get(propertyMap);

        if (value == null) {
            return null;
        }

        // Object within the map
        EventBean theEvent = (EventBean) value;
        return eventBeanEntryGetter.getFragment(theEvent);
    }

    private CodegenMethodNode getFragmentCodegen(CodegenMethodScope codegenMethodScope, CodegenClassScope codegenClassScope) {
        return codegenMethodScope.makeChild(Object.class, this.getClass(), codegenClassScope).addParam(Map.class, "map").getBlock()
                .declareVar(Object.class, "value", exprDotMethod(ref("map"), "get", constant(propertyMap)))
                .ifRefNullReturnNull("value")
                .declareVar(EventBean.class, "theEvent", cast(EventBean.class, ref("value")))
                .methodReturn(eventBeanEntryGetter.eventBeanFragmentCodegen(ref("theEvent"), codegenMethodScope, codegenClassScope));
    }

    public CodegenExpression eventBeanGetCodegen(CodegenExpression beanExpression, CodegenMethodScope codegenMethodScope, CodegenClassScope codegenClassScope) {
        return underlyingGetCodegen(castUnderlying(Map.class, beanExpression), codegenMethodScope, codegenClassScope);
    }

    public CodegenExpression eventBeanExistsCodegen(CodegenExpression beanExpression, CodegenMethodScope codegenMethodScope, CodegenClassScope codegenClassScope) {
        return constantTrue();
    }

    public CodegenExpression eventBeanFragmentCodegen(CodegenExpression beanExpression, CodegenMethodScope codegenMethodScope, CodegenClassScope codegenClassScope) {
        return underlyingFragmentCodegen(castUnderlying(Map.class, beanExpression), codegenMethodScope, codegenClassScope);
    }

    public CodegenExpression underlyingGetCodegen(CodegenExpression underlyingExpression, CodegenMethodScope codegenMethodScope, CodegenClassScope codegenClassScope) {
        return localMethod(getMapCodegen(codegenMethodScope, codegenClassScope), underlyingExpression);
    }

    public CodegenExpression underlyingExistsCodegen(CodegenExpression underlyingExpression, CodegenMethodScope codegenMethodScope, CodegenClassScope codegenClassScope) {
        return constantTrue();
    }

    public CodegenExpression underlyingFragmentCodegen(CodegenExpression underlyingExpression, CodegenMethodScope codegenMethodScope, CodegenClassScope codegenClassScope) {
        return localMethod(getFragmentCodegen(codegenMethodScope, codegenClassScope), underlyingExpression);
    }
}