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• ExpressionDemo.java

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org.codehaus.commons.compiler.samples.ExpressionDemo Maven / Gradle / Ivy

/*
 * Janino - An embedded Java[TM] compiler
 *
 * Copyright (c) 2001-2010, Arno Unkrig
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of conditions and the
 *       following disclaimer.
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
 *       following disclaimer in the documentation and/or other materials provided with the distribution.
 *    3. The name of the author may not be used to endorse or promote products derived from this software without
 *       specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

package org.codehaus.commons.compiler.samples;

import java.util.Arrays;

import org.codehaus.commons.compiler.CompilerFactoryFactory;
import org.codehaus.commons.compiler.IExpressionEvaluator;

/**
 * A test program that allows you to play around with the {@link IExpressionEvaluator} class.
 */
public final
class ExpressionDemo extends DemoBase {

    /***/
    public static void
    main(String[] args) throws Exception {

        Class   optionalExpressionType = null;
        String[]   parameterNames         = {};
        Class[] parameterTypes         = {};
        Class[] thrownExceptions       = {};
        String[]   optionalDefaultImports = null;

        int i;
        for (i = 0; i < args.length; ++i) {
            String arg = args[i];
            if (!arg.startsWith("-")) break;
            if ("-et".equals(arg)) {
                optionalExpressionType = DemoBase.stringToType(args[++i]);
            } else
            if ("-pn".equals(arg)) {
                parameterNames = DemoBase.explode(args[++i]);
            } else
            if ("-pt".equals(arg)) {
                parameterTypes = DemoBase.stringToTypes(args[++i]);
            } else
            if ("-te".equals(arg)) {
                thrownExceptions = DemoBase.stringToTypes(args[++i]);
            } else
            if ("-di".equals(arg)) {
                optionalDefaultImports = DemoBase.explode(args[++i]);
            } else
            if ("-help".equals(arg)) {
                System.err.println("Usage:");
                System.err.println("  ExpressionDemo {  }  {  }");
                System.err.println("Compiles and evaluates the given expression and prints its value.");
                System.err.println("Valid options are");
                System.err.println(" -et                         (default: any)");
                System.err.println(" -pn         (default: none)");
                System.err.println(" -pt         (default: none)");
                System.err.println(" -te  (default: none)");
                System.err.println(" -di         (default: none)");
                System.err.println(" -help");
                System.err.println("The number of parameter names, types and values must be identical.");
                System.exit(0);
            } else
            {
                System.err.println("Invalid command line option \"" + arg + "\"; try \"-help\".");
                System.exit(1);
            }
        }

        if (i >= args.length) {
            System.err.println("Expression missing; try \"-help\".");
            System.exit(1);
        }
        final String expression = args[i++];

        if (parameterTypes.length != parameterNames.length) {
            System.err.println(
                "Parameter type count ("
                + parameterTypes.length
                + ") and parameter name count ("
                + parameterNames.length
                + ") do not match; try \"-help\"."
            );
            System.exit(1);
        }

        // One command line argument for each parameter.
        if (args.length - i != parameterNames.length) {
            System.err.println(
                "Parameter value count ("
                + (args.length - i)
                + ") and parameter name count ("
                + parameterNames.length
                + ") do not match; try \"-help\"."
            );
            System.exit(1);
        }

        // Convert command line arguments to call arguments.
        Object[] arguments = new Object[parameterNames.length];
        for (int j = 0; j < parameterNames.length; ++j) {
            arguments[j] = DemoBase.createObject(parameterTypes[j], args[i + j]);
        }

        // Create "ExpressionEvaluator" object.
        IExpressionEvaluator ee = CompilerFactoryFactory.getDefaultCompilerFactory().newExpressionEvaluator();
        if (optionalExpressionType != null) ee.setExpressionType(optionalExpressionType);
        ee.setDefaultImports(optionalDefaultImports);
        ee.setParameters(parameterNames, parameterTypes);
        ee.setThrownExceptions(thrownExceptions);
        ee.cook(expression);

        // Evaluate expression with actual parameter values.
        Object res = ee.evaluate(arguments);

        // Print expression result.
        System.out.println("Result = " + (
            res instanceof Object[]
            ? Arrays.toString((Object[]) res)
            : String.valueOf(res)
        ));
    }

    private ExpressionDemo() {}
}