eqlfuncmanager.java

CRM源码This file describes some issues that should be implemented in future and how it should be imple

/*
 * Copyright 2006-2007 Queplix Corp.
 *
 * Licensed under the Queplix Public License, Version 1.1.1 (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.queplix.com/solutions/commercial-open-source/queplix-public-license/
 *
 * 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.queplix.core.modules.eql.parser;

import com.queplix.core.error.GenericSystemException;
import com.queplix.core.modules.eql.EQLReqSubOpMemberFunc;
import com.queplix.core.utils.dao.AbstractPropertyFactory;

import java.io.InputStream;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Properties;

/**
 * <p>Function manager</p>
 * @author Baranov Andrey [ALB]
 * @version $Revision: 1.2 $ $Date: 2005/10/26 14:03:51 $
 */

public final class EQLFuncManager {

// --------------- STATIC CONSTANTS ------------------------

    private static final Class CLASS = EQLFuncManager.class;
    private static final String FILE_NAME = "eql.func.properties";

    private static final HashMap functions = new HashMap();

    // function loading...
    static {

        InputStream is = AbstractPropertyFactory.loadSysPropertiesAsStream( CLASS, FILE_NAME );
        Properties props = new Properties();

        try {
            props.load( is );

            for( Iterator it = props.keySet().iterator(); it.hasNext(); ) {
                String name = ( String ) it.next();
                String className = props.getProperty( name );
                registerFunction( name, className );
            }

        } catch( Exception ex ) {
            ex.printStackTrace();
            throw new GenericSystemException( ex );
        }
    }

// ------------- PUBLIC STATIC METHODS ---------------------

    /**
     * Register new function
     * @param name function name
     * @param funcClazzName function class name
     */
    public static synchronized void registerFunction( String name, String funcClazzName ) {

        try {
            Class funcClazz = Class.forName( funcClazzName );
            functions.put( name.toUpperCase(), funcClazz );

        } catch( ClassNotFoundException ex ) {
            ex.printStackTrace();
            throw new GenericSystemException( ex );
        }
    }

    /**
     * Get new instance of function
     * @param name function name
     * @param eqlInt EQLInterpreter object
     * @return function instance
     */
    public static EQLReqSubOpMemberFunc getFunction( String name, EQLInterpreter eqlInt ) {

        Class funcClazz = ( Class ) functions.get( name.toUpperCase() );
        if( funcClazz == null ) {
            throw new GenericSystemException( "Can't get function '" + name + "'" );
        }

        EQLReqSubOpMemberFunc func = null;
        try {
            func = ( EQLReqSubOpMemberFunc ) funcClazz.newInstance();
        } catch( Exception ex ) {
            throw new GenericSystemException( "Can't instantiate function '" + name + "'", ex );
        }

        // set EQLInterpreter mediator
        func.setEQLInt( eqlInt );

        return func;
    }

// --------------- PRIVATE METHODS -------------------------

    /**
     * Constructor
     */
    private EQLFuncManager() {}
}