factargumentmetadata.java

drools 一个开放源码的规则引擎

package org.drools.spring.metadata;

/*
 * Copyright 2005 (C) The Werken Company. All Rights Reserved.
 *
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided that the
 * following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright statements and
 * notices. Redistributions must also contain a copy of this document.
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 * 2. Redistributions in binary form must reproduce the above copyright notice,
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 * from this Software without prior written permission of The Werken Company.
 * For written permission, please contact [e-mail].
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 * 4. Products derived from this Software may not be called "drools" nor may
 * "drools" appear in their names without prior written permission of The Werken
 * Company. "drools" is a registered trademark of The Werken Company.
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 * 5. Due credit should be given to The Werken Company.
 * (http://drools.werken.com/).
 *
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import org.drools.DroolsException;
import org.drools.rule.Declaration;
import org.drools.rule.Rule;
import org.drools.spring.pojorule.Argument;
import org.drools.spring.pojorule.FactArgument;

public final class FactArgumentMetadata implements ArgumentMetadata {

    static final String BASE_DEFAULT_IDENTIFIER = "Fact$";

    private String identifier;
    private final Class parameterClass;

    public FactArgumentMetadata(String identifier, Class parameterClass) {
        if (parameterClass == null) {
            throw new IllegalArgumentException("parameterClass must not be null");
        }
        if (identifier == null || identifier.trim().length() == 0) {
            this.identifier = getDefaultIdentifier(parameterClass);
        } else {
            this.identifier = identifier;
        }
        this.parameterClass = parameterClass;
    }

    public String getIdentifier() {
        return identifier;
    }

    public Class getParameterClass() {
        return parameterClass;
    }

    public Argument createArgument(Rule rule) throws DroolsException {
        Declaration declaration = rule.getParameterDeclaration(identifier);
        if (declaration == null) {
            BeanObjectType objectType = new BeanObjectType(parameterClass);
            declaration = rule.addParameterDeclaration(identifier, objectType);
        }
        return new FactArgument(declaration);
    }

    static String getDefaultIdentifier(Class parameterClass) {
        return BASE_DEFAULT_IDENTIFIER + parameterClass.getName();
    }
}