pageparameters.java

Wicket一个开发Java Web应用程序框架。它使得开发web应用程序变得容易而轻松。 Wicket利用一个POJO data beans组件使得它可以与任何持久层技术相结合。

/*
 * 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.apache.wicket;

import java.util.Map;

import org.apache.wicket.protocol.http.RequestUtils;
import org.apache.wicket.util.string.IStringIterator;
import org.apache.wicket.util.string.StringList;
import org.apache.wicket.util.value.ValueMap;


/**
 * A typesafe abstraction and container for parameters to a requested page. Page parameters in HTTP
 * are query string values in the request URL. In other protocols, the parameters to a page might
 * come from some other source.
 * <p>
 * Pages which take a PageParameters object as an argument to their constructor can be accessed
 * directly from a URL and are known as "bookmarkable" pages since the URL is stable across sessions
 * and can be stored in a browser's bookmark database.
 * 
 * @author Jonathan Locke
 */
public final class PageParameters extends ValueMap
{
	/**
	 * Null value for page parameters
	 */
	public static final PageParameters NULL = new PageParameters();

	private static final long serialVersionUID = 1L;

	/**
	 * Constructor
	 */
	public PageParameters()
	{
		super();

		setOnRequestCycle();
	}

	/**
	 * Copy constructor.
	 * 
	 * @param parameterMap
	 *            The map to copy
	 * @see ValueMap#ValueMap(java.util.Map)
	 */
	public PageParameters(final Map parameterMap)
	{
		super(parameterMap);

		setOnRequestCycle();
	}

	/**
	 * Construct.
	 * 
	 * @param keyValuePairs
	 *            List of key value pairs separated by commas. For example, "param1=foo,param2=bar"
	 * @see ValueMap#ValueMap(String)
	 */
	public PageParameters(final String keyValuePairs)
	{
		this(keyValuePairs, ",");
	}

	/**
	 * Construct.
	 * 
	 * @param keyValuePairs
	 *            List of key value pairs separated by commas. For example, "param1=foo,param2=bar"
	 * @param delimiter
	 *            Delimiter string used to separate key/value pairs
	 * @see ValueMap#ValueMap(String)
	 * 
	 * @deprecated Please use {@link RequestUtils#decodeParameters(String, ValueMap)} to decode a
	 *             request URL, or {@link ValueMap#ValueMap(String, String)} for other usecases.
	 */
	public PageParameters(final String keyValuePairs, final String delimiter)
	{
		super();

		setOnRequestCycle();

		// We can not use ValueMaps constructor as it uses
		// VariableAssignmentParser which is more suitable for markup
		// attributes, rather than URL parameters. URL param keys for
		// examples are allowed to start with a digit (e.g. 0=xxx)
		// and quotes are not "quotes".

		// Get list of strings separated by the delimiter
		final StringList pairs = StringList.tokenize(keyValuePairs, delimiter);

		// Go through each string in the list
		for (IStringIterator iterator = pairs.iterator(); iterator.hasNext();)
		{
			// Get the next key value pair
			final String pair = iterator.next();

			final int pos = pair.indexOf('=');
			if (pos == 0)
			{
				throw new IllegalArgumentException("URL parameter is missing the lvalue: " + pair);
			}
			else if (pos != -1)
			{
				final String key = pair.substring(0, pos).trim();
				final String value = pair.substring(pos + 1).trim();

				put(key, value);
			}
			else
			{
				final String key = pair.trim();
				final String value = null;

				put(key, value);
			}
		}
	}

	public Object put(Object key, Object value)
	{
		return super.put(key, value);
/*
 * BRING BACK IN 1.4
 * 
 * if (!(key instanceof String)) { throw new IllegalArgumentException( "PageParameter keys must be
 * of type String, but you supplied a " + key.getClass().getName()); } if (value instanceof String ||
 * value instanceof String[]) { return super.put(key, value); } else { throw new
 * IllegalArgumentException("You tried to add an object of type " + value.getClass().getName() + "
 * to your PageParameters for key " + key + ", but you are only allowed to use String or
 * String[]."); }
 */
	}

	/**
	 * Set this on request cycle. The RequestCycle will decide whether to keep it as a reference or
	 * not.
	 * 
	 * @see RequestCycle#setPageParameters(PageParameters)
	 */
	private void setOnRequestCycle()
	{
		RequestCycle cycle = RequestCycle.get();
		if (cycle != null)
		{
			cycle.setPageParameters(this);
		}
	}
}