ca.hedlund.jiss.preprocessor.LangPreprocessor.java Source code

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Here is the source code for ca.hedlund.jiss.preprocessor.LangPreprocessor.java

Source

/*
 * jiss-core
 * Copyright (C) 2015, Gregory Hedlund <ghedlund@mun.ca>
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package ca.hedlund.jiss.preprocessor;

import java.util.ArrayList;
import java.util.List;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import javax.script.ScriptEngineManager;

import org.apache.commons.lang3.StringEscapeUtils;

import ca.hedlund.jiss.JissModel;
import ca.hedlund.jiss.JissPreprocessor;

/**
 * Pre-processor for built-in commands.
 *
 */
public class LangPreprocessor implements JissPreprocessor {

    @Override
    public boolean preprocessCommand(JissModel jissModel, String orig, StringBuffer cmd) {
        final String c = cmd.toString();
        if (c.equals("::langs")) {
            cmd.setLength(0);
            printLangs(jissModel, cmd);
        } else if (c.equals("::lang")) {
            cmd.setLength(0);
            printCurrentLang(jissModel, cmd);
        } else if (c.startsWith("::lang")) {
            cmd.setLength(0);

            final String parts[] = c.split("\\p{Space}");
            if (parts.length == 2) {
                final String lang = parts[1];

                final ScriptEngineManager manager = new ScriptEngineManager(JissModel.class.getClassLoader());
                ScriptEngine newEngine = null;
                for (ScriptEngineFactory factory : manager.getEngineFactories()) {
                    if (factory.getLanguageName().equals(lang) || factory.getExtensions().contains(lang)
                            || factory.getMimeTypes().contains(lang)) {
                        newEngine = factory.getScriptEngine();
                        break;
                    }
                }

                if (newEngine != null) {
                    jissModel.setScriptEngine(newEngine);
                    printCurrentLang(jissModel, cmd);
                }
            }
        }
        return false;
    }

    private void printCurrentLang(JissModel model, StringBuffer cmd) {
        final List<String> cmds = new ArrayList<String>();

        final ScriptEngineFactory factory = model.getScriptEngine().getFactory();
        final String engineInfo = factory.getLanguageName() + " " + factory.getLanguageVersion() + ":"
                + factory.getEngineName() + " " + factory.getEngineVersion();
        cmds.add(createPrintCmd(model, engineInfo));

        final String prog = StringEscapeUtils.unescapeJava(factory.getProgram(cmds.toArray(new String[0])));
        cmd.append(prog);
    }

    private void printLangs(JissModel model, StringBuffer cmd) {
        final ScriptEngineManager manager = new ScriptEngineManager(JissModel.class.getClassLoader());
        final List<String> cmds = new ArrayList<String>();

        for (ScriptEngineFactory factory : manager.getEngineFactories()) {
            final String engineInfo = factory.getLanguageName() + " " + factory.getLanguageVersion() + ":"
                    + factory.getEngineName() + " " + factory.getEngineVersion();
            cmds.add(createPrintCmd(model, engineInfo));
        }
        final ScriptEngineFactory factory = model.getScriptEngine().getFactory();
        final String prog = StringEscapeUtils.unescapeJava(factory.getProgram(cmds.toArray(new String[0])));
        cmd.append(prog);
    }

    private String createPrintCmd(JissModel model, String toPrint) {
        final ScriptEngineFactory factory = model.getScriptEngine().getFactory();
        try {
            boolean includeQuotes = factory.getOutputStatement(new String()).indexOf('\"') < 0;
            final String cmd = factory
                    .getOutputStatement((includeQuotes ? "\"" : "") + toPrint + (includeQuotes ? "\"" : ""));
            return cmd;
        } catch (Exception e) {
            return "";
        }
    }
}