source: java/main/src/main/java/com/framsticks/parsers/MultiParamLoader.java @ 77

package com.framsticks.parsers;

import com.framsticks.params.*;
import org.apache.log4j.Logger;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.*;

public class MultiParamLoader {
        private final static Logger logger = Logger
                        .getLogger(MultiParamLoader.class.getName());

        /**
         * The class which name was recently found in the file, to which execution
         * should be passed.
         */
        public AccessInterface getLastAccessInterface() {
                return lastAccessInterface;
        }

        /** TODO does it support multilines? */
        /**
         * Specifies the condition to break execution.
         */
        public enum Status {
                None, Finished, BeforeObject, AfterObject, BeforeUnknown, OnComment, OnError, Loading
        }

        /**
         * Specifies the action that should be taken inside loops.
         */
        private enum LoopAction {
                Nothing, Break, Continue
        }

        protected AccessInterface lastAccessInterface;

        /**
         * Empty Param representing unknown classes - used to omit unknown
         * objects in the file.
         */
        protected AccessInterface emptyParam = new PropertiesAccess(new FramsClass());

        /**
         * Last comment found in the file.
         */
        protected String lastComment;

        /**
         * Set of break conditions.
         */
        private EnumSet<Status> breakConditions = EnumSet.of(Status.None);

        /**
         * Status of current execution.
         */
        private Status status;

        /**
         * File from which data should be read.
         */
        private SourceInterface currentSource;


        /**
         * All the files read by the loader (there could be many of them because of
         * '#|include').
         */
        private Stack<String> fileStack = new Stack<String>();

        /**
         * A map that specifies connection between the getName of the file and the
         * actual reader.
         */
        private Map<String, SourceInterface> fileMap = new HashMap<String, SourceInterface>();

        /**
         * List of known classes.
         */
        private Map<String, AccessInterface> knownParamInterfaces = new HashMap<String, AccessInterface>();

        /**
         * Last unknown object found in the file.
         */
        private String lastUnknownObjectName;

        public MultiParamLoader() {

        }

        /**
         * Starts reading the file.
         */
        public Status go() throws Exception {
                logger.trace("go");

                while (!isFinished()) {
                        // check if we are before some known or unknown object
                        LoopAction loopAction = tryReadObject();
                        if (loopAction == LoopAction.Break) {
                                break;
                        } else if (loopAction == LoopAction.Continue) {
                                continue;
                        }

                        // read data
                        String line = currentSource.readLine();

                        // end of file
                        if (line == null) {
                                if (!returnFromIncluded()) {
                                        finish();
                                        break;
                                } else {
                                        continue;
                                }
                        }

                        // empty line
                        if (line.length() == 0) {
                                continue;
                        }

                        // check if some file should be included
                        if (isIncludeLine(line) == LoopAction.Continue) {
                                continue;
                        }

                        // check if should break on comment
                        if (isCommentLine(line) == LoopAction.Break) {
                                break;
                        }

                        // get class getName
                        if (changeCurrentParamInterface(line) == LoopAction.Break) {
                                break;
                        }
                }

                return status;
        }

        /**
         * Checks whether the reader found a known or unknown object and execution
         * should be passed to it.
         */
        private LoopAction tryReadObject() throws Exception {
                if (status == Status.BeforeObject
                                || (status == Status.BeforeUnknown && lastAccessInterface != null)) {
                        // found object - let it load data
            if (lastAccessInterface.getSelected() == null) {
                lastAccessInterface.select(lastAccessInterface.createAccessee());
            }
                        lastAccessInterface.load(currentSource);

                        if (isBreakCondition(Status.AfterObject)) {
                                // break after object creation
                                return LoopAction.Break;
                        }

                        return LoopAction.Continue;
                } else if (status == Status.BeforeUnknown) {
                        logger.info("Omitting unknown object: " + lastUnknownObjectName);

                        // found unknown object
                        emptyParam.load(currentSource);
                        status = Status.AfterObject;

                        return LoopAction.Continue;
                }

                return LoopAction.Nothing;
        }

        /**
         * Checks whether some additional file shouldn't be included.
         */
        private LoopAction isIncludeLine(String line) throws FileNotFoundException {
                try {
                        // found comment
                        if (line.charAt(0) == '#') {
                                // maybe we should include something
                                if (line.substring(1, 8).equals("include")) {
                                        int beg = line.indexOf('\"');
                                        if (beg == -1) {
                                                logger.info("Wanted to include some file, but the format is incorrect");
                                                return LoopAction.Continue;
                                        }

                                        String includeFileName = line.substring(beg + 1);
                                        int end = includeFileName.indexOf('\"');
                                        if (end == -1) {
                                                logger.info("Wanted to include some file, but the format is incorrect");
                                                return LoopAction.Continue;
                                        }

                                        includeFileName = includeFileName.substring(0, end);

                                        include(includeFileName);

                                        return LoopAction.Continue;
                                }
                        }
                } catch (IndexOutOfBoundsException ex) {
                        // value after # sign is shorter than expected 7 characters - do
                        // nothing
                }

                return LoopAction.Nothing;
        }

        /**
         * Checks whether execution shouldn't break on comment.
         */
        private LoopAction isCommentLine(String line) {
                if (line.charAt(0) == '#' && isBreakCondition(Status.OnComment)) {
                        // it's a simple comment - maybe we should break?
                        lastComment = line;
                        return LoopAction.Break;
                }

                return LoopAction.Nothing;
        }

        /**
         * Gets the getName of the class from line read from file.
         */
        private LoopAction changeCurrentParamInterface(String line) {
                // found key - value line
                if (line.charAt(line.length() - 1) == ':') {
                        String typeName = line.substring(0, line.length() - 1);
                        lastAccessInterface = knownParamInterfaces.get(typeName);

                        if (lastAccessInterface != null) {
                                if (isBreakCondition(Status.BeforeObject)) {
                                        logger.info("Breaking before object");
                                        return LoopAction.Break;
                                }
                        } else {
                                lastUnknownObjectName = typeName;
                                if (isBreakCondition(Status.BeforeUnknown)) {
                                        logger.info("Breaking before unknown");
                                        return LoopAction.Break;
                                }
                        }
                }
                return LoopAction.Nothing;
        }

        /**
         * Adds another break condition.
         */
        public void addBreakCondition(Status condition) {
                breakConditions.add(condition);
        }

        /**
         * Removes break condition.
         */
        public void removeBreakCondition(Status condition) {
                breakConditions.remove(condition);
        }

        /**
         * Adds another class.
         */
        public void addAccessInterface(AccessInterface accessInterface) {
                /**TODO: by id or by name? rather by id, because from file is always lowercase*/
                knownParamInterfaces.put(accessInterface.getId(), accessInterface);
        }

        /**
         * Checks whether execution is finished.
         */
        private boolean isFinished() {
                return (status == Status.Finished);
        }

        private void finish() {
                if (currentSource != null) {
                        currentSource.close();
                }

                status = Status.Finished;
        }

        /**
         * Opens selected file.
         */

        public boolean setNewSource(SourceInterface source) {
                logger.debug("switching current source to " + source.getFilename() + "...");

                currentSource = source;
                status = Status.Loading;

                return true;
        }

        /**
         * Includes specified file.
         */
        private void include(String includeFilename) {

                includeFilename = currentSource.demangleInclude(includeFilename);

                if (includeFilename == null) {
                        return;
                }
                // check if it is already included and break if it is
                if (isAlreadyIncluded(includeFilename)) {
                        logger.debug("circular reference ignored (" + includeFilename
                                        + ")");
                        return;
                }

                logger.info("including file " + includeFilename + "...");

                SourceInterface newSource = currentSource.openInclude(includeFilename);
                if (newSource == null) {
                        return;
                }

                fileStack.add(currentSource.getFilename());
                fileMap.put(currentSource.getFilename(), currentSource);
                setNewSource(newSource);

        }

        /**
         * Checks whether selected file was already included.
         */
        private boolean isAlreadyIncluded(String filename) {
                for (String file : fileStack) {
                        if (filename.equals(file)) {
                                logger.warn("file " + filename + " was already included");
                                return true;
                        }
                }

                return false;
        }

        /**
         * Returns from included file.
         */
        private boolean returnFromIncluded() throws IOException {
                if (fileStack.size() == 0) {
                        return false;
                }

                if (currentSource != null) {
                        currentSource.close();
                }

                String filename = fileStack.pop();
                currentSource = fileMap.get(filename);
                fileMap.remove(filename);

                return true;
        }

        /**
         * Checks whether execution should break on selected condition.
         */
        private boolean isBreakCondition(Status condition) {
                status = condition;
                return breakConditions.contains(condition);
        }

        public Object returnObject() {
                Object result = lastAccessInterface.getSelected();
                if (result == null) {
                        return null;
                }
        lastAccessInterface.select(null);
                return result;
        }
}