URIWriter.java

/*
 * Copyright (C) 2011 eXo Platform SAS.
 *
 * This 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 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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 software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.web.controller.router;

import java.io.IOException;
import java.util.EnumMap;
import java.util.Map;

import org.exoplatform.web.url.MimeType;

/**
 * An uri writer.
 *
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 */
public final class URIWriter {

    /** . */
    private static final Map<MimeType, String> AMP_MAP = new EnumMap<MimeType, String>(MimeType.class);

    static {
        AMP_MAP.put(MimeType.XHTML, "&");
        AMP_MAP.put(MimeType.PLAIN, "&");
    }

    /** . */
    private MimeType mimeType;

    /** . */
    private Appendable appendable;

    /** . */
    private boolean questionMarkDone;

    /** . */
    private String amp;

    /**
     * Create a new URI writer.
     *
     * @param appendable the appendable
     * @param mimeType the mime type
     * @throws NullPointerException if the appendable argument is null
     */
    public URIWriter(Appendable appendable, MimeType mimeType) throws NullPointerException {
        if (appendable == null) {
            throw new NullPointerException("No null appendable accepted");
        }

        //
        this.appendable = appendable;
        this.mimeType = mimeType;
    }

    /**
     * Create a new URI writer.
     *
     * @param appendable the appendable
     * @throws NullPointerException if the appendable argument is null
     */
    public URIWriter(Appendable appendable) throws NullPointerException {
        this(appendable, null);
    }

    public MimeType getMimeType() {
        return mimeType;
    }

    public void setMimeType(MimeType mimeType) {
        this.mimeType = mimeType;
    }

    public void append(char c) throws IOException {
        appendable.append(c);
    }

    public void append(String s) throws IOException {
        appendable.append(s);
    }

    /**
     * Append a segment to the path.
     *
     * @param c the char to append
     * @throws IllegalStateException if a query parameter was already appended
     * @throws IOException any IO exception
     */
    public void appendSegment(char c) throws IllegalStateException, IOException {
        if (questionMarkDone) {
            throw new IllegalStateException("Query separator already written");
        }
        PercentEncoding.PATH_SEGMENT.encode(c, appendable);
    }

    /**
     * Append a segment to the path.
     *
     * @param s the string to append.
     * @throws NullPointerException if any argument value is null
     * @throws IllegalStateException if a query parameter was already appended
     * @throws IOException any IO exception
     */
    public void appendSegment(String s) throws NullPointerException, IllegalStateException, IOException {
        if (s == null) {
            throw new NullPointerException("No null path accepted");
        }
        for (int len = s.length(), i = 0; i < len; i++) {
            char c = s.charAt(i);
            appendSegment(c);
        }
    }

    /**
     * Append a query parameter to the parameter set. Note that the query parameters are ordered and the sequence of call to
     * this method should be honoured when an URL is generated. Note also that the same parameter name can be used multiple
     * times.
     *
     * @param parameterName the parameter name
     * @param paramaterValue the parameter value
     * @throws NullPointerException if any argument value is null
     * @throws IOException any IOException
     */
    public void appendQueryParameter(String parameterName, String paramaterValue) throws NullPointerException, IOException {
        if (parameterName == null) {
            throw new NullPointerException("No null parameter name accepted");
        }
        if (paramaterValue == null) {
            throw new NullPointerException("No null parameter value accepted");
        }

        //
        if (amp == null) {
            MimeType mt = mimeType;
            if (mt == null) {
                mt = MimeType.XHTML;
            }
            amp = AMP_MAP.get(mt);
        }

        //
        appendable.append(questionMarkDone ? amp : "?");
        PercentEncoding.QUERY_PARAM.encode(parameterName, appendable);
        appendable.append('=');
        PercentEncoding.QUERY_PARAM.encode(paramaterValue, appendable);
        questionMarkDone = true;
    }

    /**
     * Reset the writer for reuse.
     *
     * @param appendable the used appendable
     */
    public void reset(Appendable appendable) {
        this.appendable = appendable;
        this.questionMarkDone = false;
    }
}