GraphAnswer

/*
 * Zemucan: A Syntax Assistant for DB2
 * Copyright (C) 2009, 2010 Andres Gomez Casanova
 *
 * This file is part of Zemucan.
 *
 * Zemucan is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * Zemucan 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, see <http://www.gnu.org/licenses/>.
 *
 * Contact:
 * a n g o c a  at  y a h o o  dot  c o m
 * Cra. 45 No 61 - 31, Bogota, Colombia.
 *
 * Author:   $LastChangedBy: angoca $:
 * Date:     $LastChangedDate: 2011-03-06 09:19:05 -0500 (dom, 06 mar 2011) $:
 * Revision: $LastChangedRevision: 1910 $:
 * URL:      $HeadURL: https://zemucan.svn.sourceforge.net/svnroot/zemucan/branches/zemucan_v1/source-code/analyzers/src/main/java/name/angoca/zemucan/core/syntactic/model/GraphAnswer.java $:
 */
package name.angoca.zemucan.core.syntactic.model;

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

import name.angoca.zemucan.GeneralException;
import name.angoca.zemucan.core.lexical.model.Token;

/**
 * Represents the answer of a given command. An answer is the phrase completed
 * or the possible options of the current phrase.
 * <p>
 * This object is immutable, once it is created, their properties cannot be
 * changed. This is the reason because there are not setter methods. The getters
 * return a copy of the objects in order to prevent an internal modification
 * from an external context.
 * <p>
 * This object returns always a copy of its members.
 * <p>
 * <b>Control Version</b>
 * <p>
 * <ul>
 * <li>0.0.1 Class creation.</li>
 * <li>0.1.0</li>
 * <li>0.2.0</li>
 * <li>0.3.0 Recommendations from PMD.</li>
 * <li>0.3.1 Organized.</li>
 * <li>0.3.2 not null check.</li>
 * <li>1.0.0 Moved to version 1.</li>
 * <li>1.1.0 asserts.</li>
 * <li>1.1.1 equals fix it.</li>
 * <li>1.2.0 Clonable.</li>
 * </ul>
 *
 * @author Andres Gomez Casanova <a
 *         href="mailto:a n g o c a at y a h o o dot c o m" >(AngocA)</a>
 * @version 1.2.0 2010-05-04
 */
public final class GraphAnswer {
    /**
     * Status that indicates if asserts are enabled.
     */
    private boolean assertsEnabled;

    /**
     * Set of possible options.
     */
    private final transient List<Token> options;

    /**
     * Phrases that represents the command completed.
     */
    private final transient List<Token> phrases;

    /**
     * Constructor that associates the phrase and the possible options.
     *
     * @param graphPhrases
     *            phrase completed (could be the same that the user wrote.)
     * @param graphOptions
     *            Possible options (0..n)
     */
    public GraphAnswer(final List<Token>/* <!>! */graphPhrases,
            final List<Token>/* <!>! */graphOptions) {
        assert graphPhrases != null;
        assert graphOptions != null;
        this.assertsEnabled = false;
        // Intentional side-effect!
        assert this.assertsEnabled = true;
        if (this.assertsEnabled) {
            for (final Token token : graphPhrases) {
                assert token != null;
            }
            for (final Token token : graphOptions) {
                assert token != null;
            }
        }

        this.phrases = graphPhrases;
        this.options = graphOptions;
    }

    /*
     * (non-Javadoc)
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(final Object/* ? */object) {
        boolean equals = false;
        if (object instanceof GraphAnswer) {
            final GraphAnswer graph = (GraphAnswer) object;
            int size = graph.options.size();
            if (size == this.options.size()) {
                equals = true;
                for (int i = 0; (i < size) && equals; i += 1) {
                    equals &= this.options.contains(graph.options.get(i));
                }
                size = graph.phrases.size();
                if (equals && (size == this.phrases.size())) {
                    for (int i = 0; (i < size) && equals; i += 1) {
                        equals &= this.phrases.contains(graph.phrases.get(i));
                    }
                } else {
                    equals = false;
                }
            }
        }
        return equals;
    }

    /**
     * Returns the set of options of the current position.
     *
     * @return set of options.
     * @throws GeneralException
     *             Problem when cloning.
     */
    public List<Token>/* <!>! */getOptions() throws GeneralException {
        assert this.options != null;
        if (this.assertsEnabled) {
            for (final Token token : this.options) {
                assert token != null;
            }
        }

        final List<Token> copy = new ArrayList<Token>();
        for (final Token node : this.options) {
            try {
                copy.add(node.clone());
            } catch (final CloneNotSupportedException e) {
                throw new GeneralException(e);
            }
        }

        return copy;
    }

    /**
     * Returns the set of phrases of the command.
     *
     * @return set of tokens that represents the command.
     * @throws GeneralException
     *             Problem when cloning.
     */
    public List<Token>/* <!>! */getPhrases() throws GeneralException {
        assert this.phrases != null;
        if (this.assertsEnabled) {
            for (final Token token : this.phrases) {
                assert token != null;
            }
        }

        final List<Token> copy = new ArrayList<Token>();
        for (final Token node : this.phrases) {
            try {
                copy.add(node.clone());
            } catch (final CloneNotSupportedException e) {
                throw new GeneralException(e);
            }
        }

        return copy;
    }

    /*
     * (non-Javadoc)
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        int ret = this.phrases.size() * this.options.size();
        for (final Token token : this.phrases) {
            ret -= token.getToken().hashCode();
        }
        for (final Token token : this.options) {
            ret += token.getToken().hashCode();
        }
        return ret;
    }

    /**
     * Returns a string representation of a graph answer. The representation is:
     * [phrases],{options}
     *
     * @see java.lang.Object#toString()
     * @return String representation of a graph answer.
     */
    @Override
    public String/* ! */toString() {
        final StringBuffer ret = new StringBuffer();
        ret.append('[');
        // Phrases
        for (final Token token : this.phrases) {
            ret.append(token.toString());
        }
        ret.append("],{"); //$NON-NLS-1$
        // Options
        for (final Token token : this.options) {
            ret.append(token.toString());
        }
        ret.append('}');
        return ret.toString();
    }
}