com.google.gwt.http.client.URL.java Source code

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/*
 * Copyright 2006 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.http.client;

/**
 * Utility class for the encoding and decoding URLs in their entirety or by
 * their individual components.
 * 
 * <h3>Required Module</h3>
 * Modules that use this class should inherit
 * <code>com.google.gwt.http.HTTP</code>.
 * 
 * {@gwt.include com/google/gwt/examples/http/InheritsExample.gwt.xml}
 */
public final class URL {

    /**
     * Returns a string where all URL escape sequences have been converted back to
     * their original character representations.
     * 
     * @param encodedURL string containing encoded URL encoded sequences
     * @return string with no encoded URL encoded sequences
     * 
     * @throws NullPointerException if encodedURL is <code>null</code>
     */
    public static String decode(String encodedURL) {
        StringValidator.throwIfNull("encodedURL", encodedURL);
        return decodeImpl(encodedURL);
    }

    /**
     * Returns a string where all URL component escape sequences have been
     * converted back to their original character representations.
     * <p>
     * Note: this method will convert the space character escape short form, '+',
     * into a space. It should therefore only be used for query-string parts.
     * 
     * @param encodedURLComponent string containing encoded URL component
     *        sequences
     * @return string with no encoded URL component encoded sequences
     * 
     * @throws NullPointerException if encodedURLComponent is <code>null</code>
     * 
     * @deprecated Use {@link #decodeQueryString(String)}
     */
    @Deprecated
    public static String decodeComponent(String encodedURLComponent) {
        return decodeQueryString(encodedURLComponent);
    }

    /**
     * Returns a string where all URL component escape sequences have been
     * converted back to their original character representations.
     * 
     * @param encodedURLComponent string containing encoded URL component
     *        sequences
     * @param fromQueryString if <code>true</code>, +'s will be turned into
     *        spaces, otherwise they'll be kept as-is.
     * @return string with no encoded URL component encoded sequences
     * 
     * @throws NullPointerException if encodedURLComponent is <code>null</code>
     * 
     * @deprecated Use {@link #decodeQueryString(String)},
     *             {@link #decodePathSegment(String)}
     */
    @Deprecated
    public static String decodeComponent(String encodedURLComponent, boolean fromQueryString) {
        StringValidator.throwIfNull("encodedURLComponent", encodedURLComponent);
        return fromQueryString ? decodeQueryStringImpl(encodedURLComponent)
                : decodePathSegmentImpl(encodedURLComponent);
    }

    /**
     * Returns a string where all URL component escape sequences have been
     * converted back to their original character representations.
     * 
     * @param encodedURLComponent string containing encoded URL component
     *          sequences
     * @return string with no encoded URL component encoded sequences
     * 
     * @throws NullPointerException if encodedURLComponent is <code>null</code>
     */
    public static String decodePathSegment(String encodedURLComponent) {
        StringValidator.throwIfNull("encodedURLComponent", encodedURLComponent);
        return decodePathSegmentImpl(encodedURLComponent);
    }

    /**
     * Returns a string where all URL component escape sequences have been
     * converted back to their original character representations.
     * <p>
     * Note: this method will convert the space character escape short form, '+',
     * into a space. It should therefore only be used for query-string parts.
     * 
     * @param encodedURLComponent string containing encoded URL component
     *          sequences
     * @return string with no encoded URL component encoded sequences
     * 
     * @throws NullPointerException if encodedURLComponent is <code>null</code>
     */
    public static String decodeQueryString(String encodedURLComponent) {
        StringValidator.throwIfNull("encodedURLComponent", encodedURLComponent);
        return decodeQueryStringImpl(encodedURLComponent);
    }

    /**
     * Returns a string where all characters that are not valid for a complete URL
     * have been escaped. The escaping of a character is done by converting it
     * into its UTF-8 encoding and then encoding each of the resulting bytes as a
     * %xx hexadecimal escape sequence.
     * 
     * <p>
     * The following character sets are <em>not</em> escaped by this method:
     * <ul>
     * <li>ASCII digits or letters</li>
     * <li>ASCII punctuation characters:
     * 
     * <pre>
     * - _ . ! ~ * ' ( )
     * </pre>
     * 
     * </li>
     * <li>URL component delimiter characters:
     * 
     * <pre>
     * ; / ? : &amp; = + $ , #
     * </pre>
     * 
     * </li>
     * </ul>
     * </p>
     * 
     * @param decodedURL a string containing URL characters that may require
     *        encoding
     * @return a string with all invalid URL characters escaped
     * 
     * @throws NullPointerException if decodedURL is <code>null</code>
     */
    public static String encode(String decodedURL) {
        StringValidator.throwIfNull("decodedURL", decodedURL);
        return encodeImpl(decodedURL);
    }

    /**
     * Returns a string where all characters that are not valid for a URL
     * component have been escaped. The escaping of a character is done by
     * converting it into its UTF-8 encoding and then encoding each of the
     * resulting bytes as a %xx hexadecimal escape sequence.
     * <p>
     * Note: this method will convert any the space character into its escape
     * short form, '+' rather than %20. It should therefore only be used for
     * query-string parts.
     * 
     * <p>
     * The following character sets are <em>not</em> escaped by this method:
     * <ul>
     * <li>ASCII digits or letters</li>
     * <li>ASCII punctuation characters:
     * 
     * <pre>- _ . ! ~ * ' ( )</pre>
     * </li>
     * </ul>
     * </p>
     * 
     * <p>
     * Notice that this method <em>does</em> encode the URL component delimiter
     * characters:<blockquote>
     * 
     * <pre>
     * ; / ? : &amp; = + $ , #
     * </pre>
     * 
     * </blockquote>
     * </p>
     * 
     * @param decodedURLComponent a string containing invalid URL characters
     * @return a string with all invalid URL characters escaped
     * 
     * @throws NullPointerException if decodedURLComponent is <code>null</code>
     * 
     * @deprecated Use {@link #encodeQueryString(String)}
     */
    @Deprecated
    public static String encodeComponent(String decodedURLComponent) {
        return encodeQueryString(decodedURLComponent);
    }

    /**
     * Returns a string where all characters that are not valid for a URL
     * component have been escaped. The escaping of a character is done by
     * converting it into its UTF-8 encoding and then encoding each of the
     * resulting bytes as a %xx hexadecimal escape sequence.
     * 
     * <p>
     * The following character sets are <em>not</em> escaped by this method:
     * <ul>
     * <li>ASCII digits or letters</li>
    +   * <li>ASCII punctuation characters:
     * 
     * <pre>- _ . ! ~ * ' ( )</pre>
     * </li>
     * </ul>
     * </p>
     * 
     * <p>
     * Notice that this method <em>does</em> encode the URL component delimiter
     * characters:<blockquote>
     * 
     * <pre>
     * ; / ? : &amp; = + $ , #
     * </pre>
     * 
     * </blockquote>
     * </p>
     * 
     * @param decodedURLComponent a string containing invalid URL characters
     * @param queryStringSpaces if <code>true</code>, spaces will be encoded as
     *          +'s.
     * @return a string with all invalid URL characters escaped
     * 
     * @throws NullPointerException if decodedURLComponent is <code>null</code>
     * 
     * @deprecated Use {@link #encodeQueryString(String)},
     *             {@link #encodePathSegment(String)}
     */
    @Deprecated
    public static String encodeComponent(String decodedURLComponent, boolean queryStringSpaces) {
        StringValidator.throwIfNull("decodedURLComponent", decodedURLComponent);
        return queryStringSpaces ? encodeQueryStringImpl(decodedURLComponent)
                : encodePathSegmentImpl(decodedURLComponent);
    }

    /**
     * Returns a string where all characters that are not valid for a URL
     * component have been escaped. The escaping of a character is done by
     * converting it into its UTF-8 encoding and then encoding each of the
     * resulting bytes as a %xx hexadecimal escape sequence.
     * 
     * <p>
     * The following character sets are <em>not</em> escaped by this method:
     * <ul>
     * <li>ASCII digits or letters</li>
     * <li>ASCII punctuation characters:
     * 
     * <pre>- _ . ! ~ * ' ( )</pre>
     * </li>
     * </ul>
     * </p>
     * 
     * <p>
     * Notice that this method <em>does</em> encode the URL component delimiter
     * characters:<blockquote>
     * 
     * <pre>
     * ; / ? : &amp; = + $ , #
     * </pre>
     * 
     * </blockquote>
     * </p>
     * 
     * @param decodedURLComponent a string containing invalid URL characters
     * @return a string with all invalid URL characters escaped
     * 
     * @throws NullPointerException if decodedURLComponent is <code>null</code>
     */
    public static String encodePathSegment(String decodedURLComponent) {
        StringValidator.throwIfNull("decodedURLComponent", decodedURLComponent);
        return encodePathSegmentImpl(decodedURLComponent);
    }

    /**
     * Returns a string where all characters that are not valid for a URL
     * component have been escaped. The escaping of a character is done by
     * converting it into its UTF-8 encoding and then encoding each of the
     * resulting bytes as a %xx hexadecimal escape sequence.
     * <p>
     * Note: this method will convert any the space character into its escape
     * short form, '+' rather than %20. It should therefore only be used for
     * query-string parts.
     * 
     * <p>
     * The following character sets are <em>not</em> escaped by this method:
     * <ul>
     * <li>ASCII digits or letters</li>
     * <li>ASCII punctuation characters:
     * 
     * <pre>- _ . ! ~ * ' ( )</pre>
     * </li>
     * </ul>
     * </p>
     * 
     * <p>
     * Notice that this method <em>does</em> encode the URL component delimiter
     * characters:<blockquote>
     * 
     * <pre>
     * ; / ? : &amp; = + $ , #
     * </pre>
     * 
     * </blockquote>
     * </p>
     * 
     * @param decodedURLComponent a string containing invalid URL characters
     * @return a string with all invalid URL characters escaped
     * 
     * @throws NullPointerException if decodedURLComponent is <code>null</code>
     */
    public static String encodeQueryString(String decodedURLComponent) {
        StringValidator.throwIfNull("decodedURLComponent", decodedURLComponent);
        return encodeQueryStringImpl(decodedURLComponent);
    }

    private static native String decodeImpl(String encodedURL) /*-{
                                                               return decodeURI(encodedURL);
                                                               }-*/;

    private static native String decodePathSegmentImpl(String encodedURLComponent) /*-{
                                                                                   return decodeURIComponent(encodedURLComponent);
                                                                                   }-*/;

    private static native String decodeQueryStringImpl(String encodedURLComponent) /*-{
                                                                                   var regexp = /\+/g;
                                                                                   return decodeURIComponent(encodedURLComponent.replace(regexp, "%20"));
                                                                                   }-*/;

    private static native String encodeImpl(String decodedURL) /*-{
                                                               return encodeURI(decodedURL);
                                                               }-*/;

    private static native String encodePathSegmentImpl(String decodedURLComponent) /*-{
                                                                                   return encodeURIComponent(decodedURLComponent);
                                                                                   }-*/;

    private static native String encodeQueryStringImpl(String decodedURLComponent) /*-{
                                                                                   var regexp = /%20/g;
                                                                                   return encodeURIComponent(decodedURLComponent).replace(regexp, "+");
                                                                                   }-*/;

    private URL() {
    }
}