MediaTypeHeaderDelegate.java

/*******************************************************************************
 * Copyright (c) 2012-2016 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.everrest.core.impl.header;

import javax.ws.rs.core.MediaType;
import javax.ws.rs.ext.RuntimeDelegate;
import java.text.ParseException;
import java.util.Map;
import java.util.Map.Entry;

import static org.everrest.core.impl.header.HeaderHelper.appendWithQuote;
import static org.everrest.core.impl.header.HeaderHelper.removeWhitespaces;
import static org.everrest.core.util.StringUtils.charAtIs;
import static org.everrest.core.util.StringUtils.charAtIsNot;
import static org.everrest.core.util.StringUtils.scan;

/**
 * @author andrew00x
 */
public class MediaTypeHeaderDelegate implements RuntimeDelegate.HeaderDelegate<MediaType> {
    private static final char SUB_TYPE_SEPARATOR = '/';
    private static final char PARAMS_SEPARATOR = ';';

    @Override
    public MediaType fromString(String header) {
        if (header == null) {
            throw new IllegalArgumentException();
        }

        try {
            int subTypeSeparatorIndex = scan(header, SUB_TYPE_SEPARATOR);
            int paramsSeparatorIndex = scan(header, PARAMS_SEPARATOR);

            String type;
            String subType;

            if (charAtIsNot(header, subTypeSeparatorIndex, SUB_TYPE_SEPARATOR)
                && charAtIsNot(header, paramsSeparatorIndex, PARAMS_SEPARATOR)) {

                return new MediaType(header, null);

            } else if (charAtIs(header, subTypeSeparatorIndex, SUB_TYPE_SEPARATOR)
                       && charAtIsNot(header, paramsSeparatorIndex, PARAMS_SEPARATOR)) {

                return new MediaType(removeWhitespaces(header.substring(0, subTypeSeparatorIndex)),
                                     removeWhitespaces(header.substring(subTypeSeparatorIndex + 1)));

            } else if (charAtIsNot(header, subTypeSeparatorIndex, SUB_TYPE_SEPARATOR) && paramsSeparatorIndex == 0) {

                // string just start from ';'
                type = null;
                subType = null;

            } else if (charAtIsNot(header, subTypeSeparatorIndex, SUB_TYPE_SEPARATOR)
                       && charAtIs(header, paramsSeparatorIndex, PARAMS_SEPARATOR)) {

                // there is no '/' but present ';'
                type = removeWhitespaces(header.substring(0, paramsSeparatorIndex));
                subType = null;

            } else {

                type = removeWhitespaces(header.substring(0, subTypeSeparatorIndex));
                subType = header.substring(subTypeSeparatorIndex + 1, paramsSeparatorIndex);

            }

            Map<String, String> params = new HeaderParameterParser().parse(header);
            return new MediaType(type, subType, params);

        } catch (ParseException e) {
            throw new IllegalArgumentException(e);
        }
    }


    @Override
    public String toString(MediaType mime) {
        if (mime == null) {
            throw new IllegalArgumentException();
        }
        StringBuilder sb = new StringBuilder();
        sb.append(mime.getType()).append('/').append(mime.getSubtype());

        for (Entry<String, String> entry : mime.getParameters().entrySet()) {
            sb.append(';').append(entry.getKey()).append('=');
            appendWithQuote(sb, entry.getValue());
        }

        return sb.toString();
    }
}