org.waveprotocol.wave.client.util.UrlParameters.java Source code

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Here is the source code for org.waveprotocol.wave.client.util.UrlParameters.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.waveprotocol.wave.client.util;

import com.google.gwt.http.client.URL;

import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

/**
 * NOTE(user): Strictly speaking the initial '?' is not part of the query
 * string, but we treat it as part of the query string in this class for
 * convenience.
 *
 */
public class UrlParameters implements TypedSource {

    private static UrlParameters singleton;

    private final HashMap<String, String> map = new HashMap<String, String>();

    private static native String getQueryString() /*-{
                                                  return $wnd.location.search;
                                                  }-*/;

    UrlParameters(String query) {
        if (query.length() > 1) {
            String[] keyvalpairs = query.substring(1, query.length()).split("&");
            for (String pair : keyvalpairs) {
                String[] keyval = pair.split("=");
                // Some basic error handling for invalid query params.
                if (keyval.length == 2) {
                    map.put(URL.decodeComponent(keyval[0]), URL.decodeComponent(keyval[1]));
                } else if (keyval.length == 1) {
                    map.put(URL.decodeComponent(keyval[0]), "");
                }
            }
        }
    }

    public String getParameter(String name) {
        return map.get(name);
    }

    public static UrlParameters get() {
        if (singleton == null) {
            singleton = new UrlParameters(getQueryString());
        }
        return singleton;
    }

    /** {@inheritDoc} */
    public Boolean getBoolean(String key) {
        String value = getParameter(key);
        if (value == null) {
            return null;
        }
        return Boolean.valueOf(value);
    }

    /** {@inheritDoc} */
    public Double getDouble(String key) {
        String value = getParameter(key);
        if (value == null) {
            return null;
        }

        try {
            return Double.valueOf(value);
        } catch (NumberFormatException e) {
            return null;
        }
    }

    /** {@inheritDoc} */
    public Integer getInteger(String key) {
        String value = getParameter(key);
        if (value == null) {
            return null;
        }

        try {
            return Integer.valueOf(value);
        } catch (NumberFormatException e) {
            return null;
        }
    }

    /** {@inheritDoc} */
    public String getString(String key) {
        String value = getParameter(key);
        return value;
    }

    /**
     * Build a query string out of a map of key/value pairs.
     * @param queryEntries
     */
    public static String buildQueryString(Map<String, String> queryEntries) {
        StringBuffer sb = new StringBuffer();
        boolean firstIteration = true;
        for (Entry<String, String> e : queryEntries.entrySet()) {
            if (firstIteration) {
                sb.append('?');
            } else {
                sb.append('&');
            }
            String encodedName = URL.encodeComponent(e.getKey());
            sb.append(encodedName);

            sb.append('=');

            String encodedValue = URL.encodeComponent(e.getValue());
            sb.append(encodedValue);
            firstIteration = false;
        }
        return sb.toString();
    }
}