configurations.java

java 编写的程序

package source.org.apache.java.util;

/*
 * Copyright (c) 1997-1999 The Java Apache Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the Java Apache 
 *    Project for use in the Apache JServ servlet engine project
 *    <http://java.apache.org/>."
 *
 * 4. The names "Apache JServ", "Apache JServ Servlet Engine" and 
 *    "Java Apache Project" must not be used to endorse or promote products 
 *    derived from this software without prior written permission.
 *
 * 5. Products derived from this software may not be called "Apache JServ"
 *    nor may "Apache" nor "Apache JServ" appear in their names without 
 *    prior written permission of the Java Apache Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the Java Apache 
 *    Project for use in the Apache JServ servlet engine project
 *    <http://java.apache.org/>."
 *    
 * THIS SOFTWARE IS PROVIDED BY THE JAVA APACHE PROJECT "AS IS" AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE JAVA APACHE PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Java Apache Group. For more information
 * on the Java Apache Project and the Apache JServ Servlet Engine project,
 * please see <http://java.apache.org/>.
 *
 */

import java.util.*;
import java.io.*;

/**
 * This class is used to encapsulate properties and addresses
 * the need for a flexible, portable and fast configurations
 * repository.
 *
 * <p>While properties are just considered as strings, configurations
 * have methods to return different types such as <b>int</b> and
 * <b>long</b>.
 *
 * <p>Performance is needed to avoid the use of properties only at
 * startup to fill variables: configurations encapsulate properties
 * in the sense that objects retrieved by parsing property strings
 * are stored for faster reuse. This allows a program to use
 * configurations instead of global variables in a central repository,
 * that, if updated, will reflect instantly the changes throughout
 * the whole application.
 *
 * <p>The behavior of this class is syntax indipendent because
 * it's only an encapsulator.
 * This allows greater flexibility throught the use of syntax abstraction
 * and faster transition between different configuration syntax.
 *
 * @author <a href="mailto:[e-mail]">Stefano Mazzocchi</a>
 * @version $Revision: 1.2 $ $Date: 2000/08/08 14:01:44 $
 */
public class Configurations {

	/**
	 * Default configurations repository.
	 */
	private Configurations defaults;

	/**
	 * Configuration repository.
	 */
	private ConfigurationsRepository repository;

	/**
	 * Creates an empty configuration repository
	 * with no default values.
	 */
	public Configurations() {
		this(null, null);
	}
	/**
	 * Creates an empty configuration repository with
	 * the specified defaults.
	 *
	 * @param defaults the default values repository.
	 */
	public Configurations(Configurations defaults) {
		this(null, defaults);
	}
	/**
	 * Creates a configuration repository encapsulating
	 * the given properties with no default values.
	 *
	 * @param properties the properties to encapsulate.
	 */
	public Configurations(ConfigurationsRepository properties) {
		this(properties, null);
	}
	/**
	 * Merge the given properties object as configurations.
	 *
	 * @param properties the properties file to merge
	 */
	public Configurations(ConfigurationsRepository properties,
			Configurations defaults) {
		this.repository = properties;
		this.defaults = defaults;
	}
	/**
	 * Get a boolean associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @return the associated boolean.
	 * @exception NoSuchElementException is thrown if the key doesn't
	 * map to an existing object.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Boolean.
	 */
	public boolean getBoolean(String key) {
		Boolean b = this.getBoolean(key, (Boolean) null);
		if (b != null) {
			return b.booleanValue();
		} else {
			throw new NoSuchElementException(key
				+ " doesn't map to an existing object");
		}
	}
	/**
	 * Get a boolean associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @param defaultValue the defaul value.
	 * @return the associated boolean if key is found and has valid format,
	 * default value otherwise.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Boolean.
	 */
	public Boolean getBoolean(String key, Boolean defaultValue) {
		Object value = repository.get(key);

		if (value instanceof Boolean) {
			return (Boolean) value;
		} else if (value instanceof String) {
			Boolean b = new Boolean((String) value);
			repository.put(key, b);
			return b;
		} else if (value == null) {
			if (defaults != null) {
				return defaults.getBoolean(key, defaultValue);
			} else {
				return defaultValue;
			}
		} else {
			throw new ClassCastException(key
				+ " doesn't map to a Boolean object");
		}
	}
	/**
	 * Get a boolean associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @param defaultValue the defaul value.
	 * @return the associated boolean.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Boolean.
	 */
	public boolean getBoolean(String key, boolean defaultValue) {
		return this.getBoolean(key, new Boolean(defaultValue)).booleanValue();
	}
	/**
	 * Get a byte associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @return the associated byte.
	 * @exception NoSuchElementException is thrown if the key doesn't
	 * map to an existing object.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Byte.
	 * @exception NumberFormatException is thrown if the value
	 * mapped by the key has not a valid number format.
	 */
	public byte getByte(String key) {
		Byte b = this.getByte(key, null);
		if (b != null) {
			return b.byteValue();
		} else {
			throw new NoSuchElementException(key
				+ " doesn't map to an existing object");
		}
	}
	/**
	 * Get a byte associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @param defaultValue the defaul value.
	 * @return the associated byte.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Byte.
	 * @exception NumberFormatException is thrown if the value
	 * mapped by the key has not a valid number format.
	 */
	public byte getByte(String key, byte defaultValue) {
		return this.getByte(key, new Byte(defaultValue)).byteValue();
	}
	/**
	 * Get a byte associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @param defaultValue the defaul value.
	 * @return the associated byte if key is found and has valid format,
	 * default value otherwise.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Byte.
	 * @exception NumberFormatException is thrown if the value
	 * mapped by the key has not a valid number format.
	 */
	public Byte getByte(String key, Byte defaultValue) {
		Object value = repository.get(key);

		if (value instanceof Byte) {
			return (Byte) value;
		} else if (value instanceof String) {
			Byte b = new Byte((String) value);
			repository.put(key, b);
			return b;
		} else if (value == null) {
			if (defaults != null) {
				return defaults.getByte(key, defaultValue);
			} else {
				return defaultValue;
			}
		} else {
			throw new ClassCastException(key
				+ " doesn't map to a Byte object");
		}
	}
	/**
	 * Get a double associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @return the associated double.
	 * @exception NoSuchElementException is thrown if the key doesn't
	 * map to an existing object.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Double.
	 * @exception NumberFormatException is thrown if the value
	 * mapped by the key has not a valid number format.
	 */
	public double getDouble(String key) {
		Double d = this.getDouble(key, null);
		if (d != null) {
			return d.doubleValue();
		} else {
			throw new NoSuchElementException(key
				+ " doesn't map to an existing object");
		}
	}
	/**
	 * Get a double associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @param defaultValue the defaul value.
	 * @return the associated double.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Double.
	 * @exception NumberFormatException is thrown if the value
	 * mapped by the key has not a valid number format.
	 */
	public double getDouble(String key, double defaultValue) {
		return this.getDouble(key, new Double(defaultValue)).doubleValue();
	}
	/**
	 * Get a double associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @param defaultValue the defaul value.
	 * @return the associated double if key is found and has valid format,
	 * default value otherwise.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Double.
	 * @exception NumberFormatException is thrown if the value
	 * mapped by the key has not a valid number format.
	 */
	public Double getDouble(String key, Double defaultValue) {
		Object value = repository.get(key);

		if (value instanceof Double) {
			return (Double) value;
		} else if (value instanceof String) {
			Double d = new Double((String) value);
			repository.put(key, d);
			return d;
		} else if (value == null) {
			if (defaults != null) {
				return defaults.getDouble(key, defaultValue);
			} else {
				return defaultValue;
			}
		} else {
			throw new ClassCastException(key
				+ " doesn't map to a Double object");
		}
	}
	/**
	 * Get a float associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @return the associated float.
	 * @exception NoSuchElementException is thrown if the key doesn't
	 * map to an existing object.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Float.
	 * @exception NumberFormatException is thrown if the value
	 * mapped by the key has not a valid number format.
	 */
	public float getFloat(String key) {
		Float f = this.getFloat(key, null);
		if (f != null) {
			return f.floatValue();
		} else {
			throw new NoSuchElementException(key
				+ " doesn't map to an existing object");
		}
	}
	/**
	 * Get a float associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @param defaultValue the defaul value.
	 * @return the associated float.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Float.
	 * @exception NumberFormatException is thrown if the value
	 * mapped by the key has not a valid number format.
	 */
	public float getFloat(String key, float defaultValue) {
		return this.getFloat(key, new Float(defaultValue)).floatValue();
	}
	/**
	 * Get a float associated with the given configuration key.
	 *
	 * @param key the configuration key.
	 * @param defaultValue the defaul value.
	 * @return the associated float if key is found and has valid format,
	 * default value otherwise.
	 * @exception ClassCastException is thrown if the key maps to an
	 * object that is not a Float.
	 * @exception NumberFormatException is thrown if the value
	 * mapped by the key has not a valid number format.
	 */
	public Float getFloat(String key, Float defaultValue) {
		Object value = repository.get(key);

		if (value instanceof Float) {
			return (Float) value;
		} else if (value instanceof String) {
			Float f = new Float((String) value);
			repository.put(key, f);
			return f;
		} else if (value == null) {
			if (defaults != null) {
				return defaults.getFloat(key, defaultValue);
			} else {
				return defaultValue;
			}
		} else {