Validate.java

/*******************************************************************************
 * Copyright 2012 Geoscience Australia
 * 
 * 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 au.gov.ga.earthsci.common.util;

import java.util.Collection;

/**
 * Util class that provides some commonly used validation methods.
 * <p/>
 * Based on the Apache Commons Validate class
 * 
 * @author James Navin (james.navin@ga.gov.au)
 */
public class Validate
{

	private static final String DEFAULT_NOT_NULL_MSG = "Value cannot be null"; //$NON-NLS-1$
	private static final String DEFAULT_NOT_EMPTY_MSG = "Value cannot be empty"; //$NON-NLS-1$
	private static final String DEFAULT_IS_TRUE_MSG = "Value is false when expected true"; //$NON-NLS-1$
	private static final String DEFAULT_NOT_BLANK_MSG = "Value cannot be blank"; //$NON-NLS-1$


	/**
	 * Validate that the provided object is not <code>null</code>.
	 * 
	 * @param object
	 *            The object to validate
	 * @param msg
	 *            The message to include in any generated exceptions
	 * 
	 * @throws IllegalArgumentException
	 *             if the provided object is <code>null</code>
	 */
	public static void notNull(Object object, String msg) throws IllegalArgumentException
	{
		if (object == null)
		{
			throw new IllegalArgumentException(msg == null ? DEFAULT_NOT_NULL_MSG : msg);
		}
	}

	/**
	 * Validate that the provided boolean value is <code>true</code>.
	 * 
	 * @param value
	 *            The value to validate
	 * @param msg
	 *            The message to include in any generated exceptions
	 * 
	 * @throws IllegalArgumentException
	 *             if the provided boolean value is <code>false</code>
	 */
	public static void isTrue(boolean value, String msg) throws IllegalArgumentException
	{
		if (value == false)
		{
			throw new IllegalArgumentException(msg == null ? DEFAULT_IS_TRUE_MSG : msg);
		}
	}

	/**
	 * Validate that the provided collection is not <code>null</code> or empty.
	 * 
	 * @param value
	 *            The value to validate
	 * @param msg
	 *            The message to include in any generated exceptions
	 * 
	 * @throws IllegalArgumentException
	 *             If the provided collection is <code>null</code> or empty
	 */
	public static void notEmpty(Collection<?> value, String msg) throws IllegalArgumentException
	{
		if (value == null || value.isEmpty())
		{
			throw new IllegalArgumentException(msg == null ? DEFAULT_NOT_EMPTY_MSG : msg);
		}
	}

	/**
	 * Validate that the provided string contains non-whitespace characters.
	 * 
	 * @param string
	 *            The string to validate
	 * @param msg
	 *            The message to include in any generated exceptions
	 * 
	 * @throws IllegalArgumentException
	 *             if the provided string is <code>null</code> or
	 *             <code>empty</code>
	 */
	public static void notBlank(String string, String msg)
	{
		if (string == null || string.trim().equals("")) //$NON-NLS-1$
		{
			throw new IllegalArgumentException(msg == null ? DEFAULT_NOT_BLANK_MSG : msg);
		}

	}
}