w3c.css.properties.css3.CssBackgroundAttachment Maven / Gradle / Ivy

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// $Id$
// @author Yves Lafon 

// (c) COPYRIGHT MIT, ERCIM and Keio, 2010.
// Please first read the full copyright statement in file COPYRIGHT.html

package org.w3c.css.properties.css3;

import org.w3c.css.util.ApplContext;
import org.w3c.css.util.InvalidParamException;
import org.w3c.css.values.CssExpression;
import org.w3c.css.values.CssIdent;
import org.w3c.css.values.CssLayerList;
import org.w3c.css.values.CssTypes;
import org.w3c.css.values.CssValue;

import java.util.ArrayList;

import static org.w3c.css.values.CssOperator.COMMA;

/**
 * @spec http://www.w3.org/TR/2009/CR-css3-background-20091217/#the-background-attachment
 */
public class CssBackgroundAttachment extends org.w3c.css.properties.css.CssBackgroundAttachment {

    private static CssIdent[] allowed_values;

    static {
        allowed_values = new CssIdent[3];
        allowed_values[0] = CssIdent.getIdent("scroll");
        allowed_values[1] = CssIdent.getIdent("fixed");
        allowed_values[2] = CssIdent.getIdent("local");
    }

    public static boolean isMatchingIdent(CssIdent ident) {
        for (CssIdent id : allowed_values) {
            if (id.equals(ident)) {
                return true;
            }
        }
        return false;
    }

    public static CssIdent getMatchingIdent(CssIdent ident) {
        for (CssIdent id : allowed_values) {
            if (id.equals(ident)) {
                return id;
            }
        }
        return null;
    }

    /**
     * Create a new CssBackgroundAttachment
     */
    public CssBackgroundAttachment() {
        value = initial;
    }

    /**
     * Creates a new CssBackgroundAttachment
     *
     * @param ac         the context
     * @param expression The expression for this property
     * @param check      if some length checking is required
     * @throws org.w3c.css.util.InvalidParamException
     *          Values are incorrect
     */
    public CssBackgroundAttachment(ApplContext ac, CssExpression expression,
                                   boolean check) throws InvalidParamException {

        ArrayList values = new ArrayList();
        char op;
        CssValue val;

        setByUser();

        while (!expression.end()) {
            val = expression.getValue();
            op = expression.getOperator();
            if (val.getType() != CssTypes.CSS_IDENT) {
                throw new InvalidParamException("value", val,
                        getPropertyName(), ac);
            }
            if (inherit.equals(val)) {
                // if we got inherit after other values, fail
                // if we got more than one value... fail
                if ((values.size() > 0) || (expression.getCount() > 1)) {
                    throw new InvalidParamException("value", val,
                            getPropertyName(), ac);
                }
                values.add(inherit);
            } else {
                // check that it's in the allowed values
                CssValue new_val = getMatchingIdent((CssIdent) val);
                if (new_val == null) {
                    throw new InvalidParamException("value", val,
                            getPropertyName(), ac);
                }
                values.add(new_val);
            }
            expression.next();
            // and check that values are separated by commas
            if (!expression.end() && (op != COMMA)) {
                throw new InvalidParamException("operator",
                        ((new Character(op)).toString()), ac);
            }
        }

        if (values.size() == 1) {
            value = values.get(0);
        } else {
            value = new CssLayerList(values);
        }
    }

    public CssBackgroundAttachment(ApplContext ac, CssExpression expression)
            throws InvalidParamException {
        this(ac, expression, false);
    }

    /**
     * Is the value of this property is a default value.
     * It is used by all macro for the function print
     */
    public boolean isDefault() {
        return (initial == value);
    }
}