/*
* Copyright 2009 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;
import java.util.HashMap;
import java.util.Map;
/**
* Utility class to build a URL from components.
*
* TODO(jlabanca): Add a constructor that parses an existing URL
*/
public class UrlBuilder {
/**
* The port to use when no port should be specified.
*/
public static final int PORT_UNSPECIFIED = Integer.MIN_VALUE;
/**
* A mapping of query parameters to their values.
*/
private Map<String, String[]> listParamMap = new HashMap<String, String[]>();
private String protocol = "http";
private String host = null;
private int port = PORT_UNSPECIFIED;
private String path = null;
private String hash = null;
/**
* Build the URL and return it as an encoded string.
*
* @return the encoded URL string
*/
public String buildString() {
StringBuilder url = new StringBuilder();
// http://
url.append(URL.encode(protocol)).append("://");
// http://www.google.com
if (host != null) {
url.append(URL.encode(host));
}
// http://www.google.com:80
if (port != PORT_UNSPECIFIED) {
url.append(":").append(port);
}
// http://www.google.com:80/path/to/file.html
if (path != null && !"".equals(path)) {
url.append("/").append(URL.encode(path));
}
// Generate the query string.
// http://www.google.com:80/path/to/file.html?k0=v0&k1=v1
char prefix = '?';
for (Map.Entry<String, String[]> entry : listParamMap.entrySet()) {
for (String val : entry.getValue()) {
url.append(prefix)
.append(URL.encodeQueryString(entry.getKey()))
.append('=');
if (val != null) {
// Also encodes +,& etc.
url.append(URL.encodeQueryString(val));
}
prefix = '&';
}
}
// http://www.google.com:80/path/to/file.html?k0=v0&k1=v1#token
if (hash != null) {
url.append("#").append(URL.encode(hash));
}
return url.toString();
}
/**
* Remove a query parameter from the map.
*
* @param name the parameter name
*/
public UrlBuilder removeParameter(String name) {
listParamMap.remove(name);
return this;
}
/**
* Set the hash portion of the location (ex. myAnchor or #myAnchor).
*
* @param hash the hash
*/
public UrlBuilder setHash(String hash) {
if (hash != null && hash.startsWith("#")) {
hash = hash.substring(1);
}
this.hash = hash;
return this;
}
/**
* Set the host portion of the location (ex. google.com). You can also specify
* the port in this method (ex. localhost:8888).
*
* @param host the host
*/
public UrlBuilder setHost(String host) {
// Extract the port from the host.
if (host != null && host.contains(":")) {
String[] parts = host.split(":");
if (parts.length > 2) {
throw new IllegalArgumentException(
"Host contains more than one colon: " + host);
}
try {
setPort(Integer.parseInt(parts[1]));
} catch (NumberFormatException e) {
throw new IllegalArgumentException("Could not parse port out of host: "
+ host);
}
host = parts[0];
}
this.host = host;
return this;
}
/**
* <p>
* Set a query parameter to a list of values. Each value in the list will be
* added as its own key/value pair.
*
* <p>
* <h3>Example Output</h3>
* <code>?mykey=value0&mykey=value1&mykey=value2</code>
* </p>
*
* @param key the key
* @param values the list of values
*/
public UrlBuilder setParameter(String key, String... values) {
assertNotNullOrEmpty(key, "Key cannot be null or empty", false);
assertNotNull(values,
"Values cannot null. Try using removeParameter instead.");
if (values.length == 0) {
throw new IllegalArgumentException(
"Values cannot be empty. Try using removeParameter instead.");
}
listParamMap.put(key, values);
return this;
}
/**
* Set the path portion of the location (ex. path/to/file.html).
*
* @param path the path
*/
public UrlBuilder setPath(String path) {
if (path != null && path.startsWith("/")) {
path = path.substring(1);
}
this.path = path;
return this;
}
/**
* Set the port to connect to.
*
* @param port the port, or {@link #PORT_UNSPECIFIED}
*/
public UrlBuilder setPort(int port) {
this.port = port;
return this;
}
/**
* Set the protocol portion of the location (ex. http).
*
* @param protocol the protocol
*/
public UrlBuilder setProtocol(String protocol) {
assertNotNull(protocol, "Protocol cannot be null");
if (protocol.endsWith("://")) {
protocol = protocol.substring(0, protocol.length() - 3);
} else if (protocol.endsWith(":/")) {
protocol = protocol.substring(0, protocol.length() - 2);
} else if (protocol.endsWith(":")) {
protocol = protocol.substring(0, protocol.length() - 1);
}
if (protocol.contains(":")) {
throw new IllegalArgumentException("Invalid protocol: " + protocol);
}
assertNotNullOrEmpty(protocol, "Protocol cannot be empty", false);
this.protocol = protocol;
return this;
}
/**
* Assert that the value is not null.
*
* @param value the value
* @param message the message to include with any exceptions
* @throws IllegalArgumentException if value is null
*/
private void assertNotNull(Object value, String message)
throws IllegalArgumentException {
if (value == null) {
throw new IllegalArgumentException(message);
}
}
/**
* Assert that the value is not null or empty.
*
* @param value the value
* @param message the message to include with any exceptions
* @param isState if true, throw a state exception instead
* @throws IllegalArgumentException if value is null
* @throws IllegalStateException if value is null and isState is true
*/
private void assertNotNullOrEmpty(String value, String message,
boolean isState) throws IllegalArgumentException {
if (value == null || value.length() == 0) {
if (isState) {
throw new IllegalStateException(message);
} else {
throw new IllegalArgumentException(message);
}
}
}
}