commons-configuration/commons-configuration/1.10 : org/apache/commons/configuration/Configuration.java

Configuration
http://commons.apache.org/configuration/: Tools to assist in the reading of configuration/preferences files in various formats. (The Apache Software Foundation)
The Apache Software License, Version 2.0
Konstantin Shaposhnikov (scand.com)
Jamie M. Guillemette (TD Bank)
Jorge Ferrer ()
Gabriele Garuglieri (Infoblu S.p.A)
Nicolas De Loof (Cap Gemini)
Daniel Rall (CollabNet, Inc.)
Jason van Zyl (Zenplex)
Martin Poeschl (tucana.at)
dIon Gillard (Multitask Consulting)
Henning P. Schmiedehausen
Eric Pugh (upstate.com)
Brian E. Dunbar (dunbarconsulting.org)
Emmanuel Bourg (Ariane Software)
Oliver Heger (Agfa HealthCare)
Jörg Schaible
Ralph Goers (Intuit)
/*
 * 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.commons.configuration;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.Iterator;
import java.util.List;
import java.util.Properties;

The main Configuration interface.
This interface allows accessing and manipulating a configuration object. The major part of the methods defined in this interface deals with accessing properties of various data types. There is a generic getProperty() method, which returns the value of the queried property in its raw data type. Other getter methods try to convert this raw data type into a specific data type. If this fails, a ConversionException will be thrown.
For most of the property getter methods an overloaded version exists that allows to specify a default value, which will be returned if the queried property cannot be found in the configuration. The behavior of the methods that do not take a default value in case of a missing property is not defined by this interface and depends on a concrete implementation. E.g. the AbstractConfiguration class, which is the base class of most configuration implementations provided by this package, per default returns null if a property is not found, but provides the 
setThrowExceptionOnMissing() method, with which it can be configured to throw a NoSuchElementException exception in that case. (Note that getter methods for primitive types in AbstractConfiguration always throw an exception for missing properties because there is no way of overloading the return value.)
With the addProperty() and setProperty() methods new properties can be added to a configuration or the values of properties can be changed. With clearProperty() a property can be removed. Other methods allow to iterate over the contained properties or to create a subset configuration.
Author: Commons Configuration team
Version: $Id: Configuration.java 1534064 2013-10-21 08:44:33Z henning $/**
 * <p>The main Configuration interface.</p>
 * <p>This interface allows accessing and manipulating a configuration object.
 * The major part of the methods defined in this interface deals with accessing
 * properties of various data types. There is a generic {@code getProperty()}
 * method, which returns the value of the queried property in its raw data
 * type. Other getter methods try to convert this raw data type into a specific
 * data type. If this fails, a {@code ConversionException} will be thrown.</p>
 * <p>For most of the property getter methods an overloaded version exists that
 * allows to specify a default value, which will be returned if the queried
 * property cannot be found in the configuration. The behavior of the methods
 * that do not take a default value in case of a missing property is not defined
 * by this interface and depends on a concrete implementation. E.g. the
 * {@link AbstractConfiguration} class, which is the base class
 * of most configuration implementations provided by this package, per default
 * returns <b>null</b> if a property is not found, but provides the
 * {@link AbstractConfiguration#setThrowExceptionOnMissing(boolean)
 * setThrowExceptionOnMissing()}
 * method, with which it can be configured to throw a {@code NoSuchElementException}
 * exception in that case. (Note that getter methods for primitive types in
 * {@code AbstractConfiguration} always throw an exception for missing
 * properties because there is no way of overloading the return value.)</p>
 * <p>With the {@code addProperty()} and {@code setProperty()} methods
 * new properties can be added to a configuration or the values of properties
 * can be changed. With {@code clearProperty()} a property can be removed.
 * Other methods allow to iterate over the contained properties or to create
 * a subset configuration.</p>
 *
 * @author Commons Configuration team
 * @version $Id: Configuration.java 1534064 2013-10-21 08:44:33Z henning $
 */
public interface Configuration
{
    Return a decorator Configuration containing every key from the current
Configuration that starts with the specified prefix. The prefix is
removed from the keys in the subset. For example, if the configuration
contains the following properties:
   prefix.number = 1
   prefix.string = Apache
   prefixed.foo = bar
   prefix = Jakarta
 the Configuration returned by subset("prefix") will contain the properties:    number = 1
   string = Apache
   = Jakarta
(The key for the value "Jakarta" is an empty string)

Since the subset is a decorator and not a modified copy of the initial
Configuration, any change made to the subset is available to the
Configuration, and reciprocally.
Params: prefix – The prefix used to select the properties.
See Also: SubsetConfiguration
Returns: a subset configuration/**
     * Return a decorator Configuration containing every key from the current
     * Configuration that starts with the specified prefix. The prefix is
     * removed from the keys in the subset. For example, if the configuration
     * contains the following properties:
     *
     * <pre>
     *    prefix.number = 1
     *    prefix.string = Apache
     *    prefixed.foo = bar
     *    prefix = Jakarta</pre>
     *
     * the Configuration returned by {@code subset("prefix")} will contain
     * the properties:
     *
     * <pre>
     *    number = 1
     *    string = Apache
     *    = Jakarta</pre>
     *
     * (The key for the value "Jakarta" is an empty string)
     * <p>
     * Since the subset is a decorator and not a modified copy of the initial
     * Configuration, any change made to the subset is available to the
     * Configuration, and reciprocally.
     *
     * @param prefix The prefix used to select the properties.
     * @return a subset configuration
     *
     * @see SubsetConfiguration
     */
    Configuration subset(String prefix);

    Check if the configuration is empty.
Returns: true if the configuration contains no property, false otherwise./**
     * Check if the configuration is empty.
     *
     * @return {@code true} if the configuration contains no property,
     *         {@code false} otherwise.
     */
    boolean isEmpty();

    Check if the configuration contains the specified key.
Params: key – the key whose presence in this configuration is to be tested
Returns: true if the configuration contains a value for this key, false otherwise/**
     * Check if the configuration contains the specified key.
     *
     * @param key the key whose presence in this configuration is to be tested
     *
     * @return {@code true} if the configuration contains a value for this
     *         key, {@code false} otherwise
     */
    boolean containsKey(String key);

    Add a property to the configuration. If it already exists then the value
stated here will be added to the configuration entry. For example, if
the property:
resource.loader = file
is already present in the configuration and you call
addProperty("resource.loader", "classpath")
Then you will end up with a List like the following:
["file", "classpath"]
Params: key – The key to add the property to.
value – The value to add./**
     * Add a property to the configuration. If it already exists then the value
     * stated here will be added to the configuration entry. For example, if
     * the property:
     *
     * <pre>resource.loader = file</pre>
     *
     * is already present in the configuration and you call
     *
     * <pre>addProperty("resource.loader", "classpath")</pre>
     *
     * Then you will end up with a List like the following:
     *
     * <pre>["file", "classpath"]</pre>
     *
     * @param key The key to add the property to.
     * @param value The value to add.
     */
    void addProperty(String key, Object value);

    Set a property, this will replace any previously set values. Set values
is implicitly a call to clearProperty(key), addProperty(key, value).
Params: key – The key of the property to change
value – The new value/**
     * Set a property, this will replace any previously set values. Set values
     * is implicitly a call to clearProperty(key), addProperty(key, value).
     *
     * @param key The key of the property to change
     * @param value The new value
     */
    void setProperty(String key, Object value);

    Remove a property from the configuration.
Params: key – the key to remove along with corresponding value./**
     * Remove a property from the configuration.
     *
     * @param key the key to remove along with corresponding value.
     */
    void clearProperty(String key);

    Remove all properties from the configuration.
/**
     * Remove all properties from the configuration.
     */
    void clear();

    Gets a property from the configuration. This is the most basic get method for retrieving values of properties. In a typical implementation of the Configuration interface the other get methods (that return specific data types) will internally make use of this method. On this level variable substitution is not yet performed. The returned object is an internal representation of the property value for the passed in key. It is owned by the Configuration object. So a caller should not modify this object. It cannot be guaranteed that this object will stay constant over time (i.e. further update operations on the configuration may change its internal state). 
Params: key – property to retrieve
Returns: the value to which this configuration maps the specified key, or
        null if the configuration contains no mapping for this key./**
     * Gets a property from the configuration. This is the most basic get
     * method for retrieving values of properties. In a typical implementation
     * of the {@code Configuration} interface the other get methods (that
     * return specific data types) will internally make use of this method. On
     * this level variable substitution is not yet performed. The returned
     * object is an internal representation of the property value for the passed
     * in key. It is owned by the {@code Configuration} object. So a caller
     * should not modify this object. It cannot be guaranteed that this object
     * will stay constant over time (i.e. further update operations on the
     * configuration may change its internal state).
     *
     * @param key property to retrieve
     * @return the value to which this configuration maps the specified key, or
     *         null if the configuration contains no mapping for this key.
     */
    Object getProperty(String key);

    Get the list of the keys contained in the configuration that match the
specified prefix. For instance, if the configuration contains the
following keys:
 db.user, db.pwd, db.url, window.xpos, window.ypos,
 an invocation of getKeys("db");

will return the keys below:
 db.user, db.pwd, db.url.

Note that the prefix itself is included in the result set if there is a
matching key. The exact behavior - how the prefix is actually
interpreted - depends on a concrete implementation.
Params: prefix – The prefix to test against.
See Also: getKeys()
Returns: An Iterator of keys that match the prefix./**
     * Get the list of the keys contained in the configuration that match the
     * specified prefix. For instance, if the configuration contains the
     * following keys:<br>
     * {@code db.user, db.pwd, db.url, window.xpos, window.ypos},<br>
     * an invocation of {@code getKeys("db");}<br>
     * will return the keys below:<br>
     * {@code db.user, db.pwd, db.url}.<br>
     * Note that the prefix itself is included in the result set if there is a
     * matching key. The exact behavior - how the prefix is actually
     * interpreted - depends on a concrete implementation.
     *
     * @param prefix The prefix to test against.
     * @return An Iterator of keys that match the prefix.
     * @see #getKeys()
     */
    Iterator<String> getKeys(String prefix);

    Get the list of the keys contained in the configuration. The returned iterator can be used to obtain all defined keys. Note that the exact behavior of the iterator's remove() method is specific to a concrete implementation. It may remove the corresponding property from the configuration, but this is not guaranteed. In any case it is no replacement for calling clearProperty(String) for this property. So it is highly recommended to avoid using the iterator's remove() method. 
Returns: An Iterator./**
     * Get the list of the keys contained in the configuration. The returned
     * iterator can be used to obtain all defined keys. Note that the exact
     * behavior of the iterator's {@code remove()} method is specific to
     * a concrete implementation. It <em>may</em> remove the corresponding
     * property from the configuration, but this is not guaranteed. In any case
     * it is no replacement for calling
     * {@link #clearProperty(String)} for this property. So it is
     * highly recommended to avoid using the iterator's {@code remove()}
     * method.
     *
     * @return An Iterator.
     */
    Iterator<String> getKeys();

    Get a list of properties associated with the given configuration key. This method expects the given key to have an arbitrary number of String values, each of which is of the form {code key=value}. These strings are split at the equals sign, and the key parts will become keys of the returned Properties object, the value parts become values. 
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a String/List.
IllegalArgumentException – if one of the tokens is
        malformed (does not contain an equals sign).
Returns: The associated properties if key is found./**
     * Get a list of properties associated with the given configuration key.
     * This method expects the given key to have an arbitrary number of String
     * values, each of which is of the form {code key=value}. These
     * strings are split at the equals sign, and the key parts will become
     * keys of the returned {@code Properties} object, the value parts
     * become values.
     *
     * @param key The configuration key.
     * @return The associated properties if key is found.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a String/List.
     *
     * @throws IllegalArgumentException if one of the tokens is
     *         malformed (does not contain an equals sign).
     */
    Properties getProperties(String key);

    Get a boolean associated with the given configuration key.
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Boolean.
Returns: The associated boolean./**
     * Get a boolean associated with the given configuration key.
     *
     * @param key The configuration key.
     * @return The associated boolean.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Boolean.
     */
    boolean getBoolean(String key);

    Get a boolean associated with the given configuration key.
If the key doesn't map to an existing object, the default value
is returned.
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Boolean.
Returns: The associated boolean./**
     * Get a boolean associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated boolean.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Boolean.
     */
    boolean getBoolean(String key, boolean defaultValue);

    Get a Boolean associated with the given configuration key. 
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Boolean.
Returns: The associated boolean if key is found and has valid
        format, default value otherwise./**
     * Get a {@link Boolean} associated with the given configuration key.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated boolean if key is found and has valid
     *         format, default value otherwise.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Boolean.
     */
    Boolean getBoolean(String key, Boolean defaultValue);

    Get a byte associated with the given configuration key.
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Byte.
Returns: The associated byte./**
     * Get a byte associated with the given configuration key.
     *
     * @param key The configuration key.
     * @return The associated byte.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Byte.
     */
    byte getByte(String key);

    Get a byte associated with the given configuration key.
If the key doesn't map to an existing object, the default value
is returned.
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Byte.
Returns: The associated byte./**
     * Get a byte associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated byte.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Byte.
     */
    byte getByte(String key, byte defaultValue);

    Get a Byte associated with the given configuration key. 
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an object that
        is not a Byte.
Returns: The associated byte if key is found and has valid format, default
        value otherwise./**
     * Get a {@link Byte} associated with the given configuration key.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated byte if key is found and has valid format, default
     *         value otherwise.
     *
     * @throws ConversionException is thrown if the key maps to an object that
     *         is not a Byte.
     */
    Byte getByte(String key, Byte defaultValue);

    Get a double associated with the given configuration key.
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Double.
Returns: The associated double./**
     * Get a double associated with the given configuration key.
     *
     * @param key The configuration key.
     * @return The associated double.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Double.
     */
    double getDouble(String key);

    Get a double associated with the given configuration key.
If the key doesn't map to an existing object, the default value
is returned.
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Double.
Returns: The associated double./**
     * Get a double associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated double.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Double.
     */
    double getDouble(String key, double defaultValue);

    Get a Double associated with the given configuration key. 
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Double.
Returns: The associated double if key is found and has valid
        format, default value otherwise./**
     * Get a {@link Double} associated with the given configuration key.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated double if key is found and has valid
     *         format, default value otherwise.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Double.
     */
    Double getDouble(String key, Double defaultValue);

    Get a float associated with the given configuration key.
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Float.
Returns: The associated float./**
     * Get a float associated with the given configuration key.
     *
     * @param key The configuration key.
     * @return The associated float.
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Float.
     */
    float getFloat(String key);

    Get a float associated with the given configuration key.
If the key doesn't map to an existing object, the default value
is returned.
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Float.
Returns: The associated float./**
     * Get a float associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated float.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Float.
     */
    float getFloat(String key, float defaultValue);

    Get a Float associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned. 
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Float.
Returns: The associated float if key is found and has valid
        format, default value otherwise./**
     * Get a {@link Float} associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated float if key is found and has valid
     *         format, default value otherwise.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Float.
     */
    Float getFloat(String key, Float defaultValue);

    Get a int associated with the given configuration key.
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Integer.
Returns: The associated int./**
     * Get a int associated with the given configuration key.
     *
     * @param key The configuration key.
     * @return The associated int.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Integer.
     */
    int getInt(String key);

    Get a int associated with the given configuration key.
If the key doesn't map to an existing object, the default value
is returned.
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Integer.
Returns: The associated int./**
     * Get a int associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated int.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Integer.
     */
    int getInt(String key, int defaultValue);

    Get an Integer associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned. 
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an object that
        is not a Integer.
Returns: The associated int if key is found and has valid format, default
        value otherwise./**
     * Get an {@link Integer} associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated int if key is found and has valid format, default
     *         value otherwise.
     *
     * @throws ConversionException is thrown if the key maps to an object that
     *         is not a Integer.
     */
    Integer getInteger(String key, Integer defaultValue);

    Get a long associated with the given configuration key.
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Long.
Returns: The associated long./**
     * Get a long associated with the given configuration key.
     *
     * @param key The configuration key.
     * @return The associated long.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Long.
     */
    long getLong(String key);

    Get a long associated with the given configuration key.
If the key doesn't map to an existing object, the default value
is returned.
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Long.
Returns: The associated long./**
     * Get a long associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated long.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Long.
     */
    long getLong(String key, long defaultValue);

    Get a Long associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned. 
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Long.
Returns: The associated long if key is found and has valid
format, default value otherwise./**
     * Get a {@link Long} associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated long if key is found and has valid
     * format, default value otherwise.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Long.
     */
    Long getLong(String key, Long defaultValue);

    Get a short associated with the given configuration key.
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Short.
Returns: The associated short./**
     * Get a short associated with the given configuration key.
     *
     * @param key The configuration key.
     * @return The associated short.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Short.
     */
    short getShort(String key);

    Get a short associated with the given configuration key.
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Short.
Returns: The associated short./**
     * Get a short associated with the given configuration key.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated short.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Short.
     */
    short getShort(String key, short defaultValue);

    Get a Short associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned. 
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a Short.
Returns: The associated short if key is found and has valid
        format, default value otherwise./**
     * Get a {@link Short} associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated short if key is found and has valid
     *         format, default value otherwise.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a Short.
     */
    Short getShort(String key, Short defaultValue);

    Get a BigDecimal associated with the given configuration key. 
Params: key – The configuration key.
Returns: The associated BigDecimal if key is found and has valid format/**
     * Get a {@link BigDecimal} associated with the given configuration key.
     *
     * @param key The configuration key.
     * @return The associated BigDecimal if key is found and has valid format
     */
    BigDecimal getBigDecimal(String key);

    Get a BigDecimal associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned. 
Params: key –          The configuration key.
defaultValue – The default value.
Returns: The associated BigDecimal if key is found and has valid
        format, default value otherwise./**
     * Get a {@link BigDecimal} associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key          The configuration key.
     * @param defaultValue The default value.
     *
     * @return The associated BigDecimal if key is found and has valid
     *         format, default value otherwise.
     */
    BigDecimal getBigDecimal(String key, BigDecimal defaultValue);

    Get a BigInteger associated with the given configuration key. 
Params: key – The configuration key.
Returns: The associated BigInteger if key is found and has valid format/**
     * Get a {@link BigInteger} associated with the given configuration key.
     *
     * @param key The configuration key.
     *
     * @return The associated BigInteger if key is found and has valid format
     */
    BigInteger getBigInteger(String key);

    Get a BigInteger associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned. 
Params: key –          The configuration key.
defaultValue – The default value.
Returns: The associated BigInteger if key is found and has valid
        format, default value otherwise./**
     * Get a {@link BigInteger} associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key          The configuration key.
     * @param defaultValue The default value.
     *
     * @return The associated BigInteger if key is found and has valid
     *         format, default value otherwise.
     */
    BigInteger getBigInteger(String key, BigInteger defaultValue);

    Get a string associated with the given configuration key.
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an object that
        is not a String.
Returns: The associated string./**
     * Get a string associated with the given configuration key.
     *
     * @param key The configuration key.
     * @return The associated string.
     *
     * @throws ConversionException is thrown if the key maps to an object that
     *         is not a String.
     */
    String getString(String key);

    Get a string associated with the given configuration key.
If the key doesn't map to an existing object, the default value
is returned.
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an object that
        is not a String.
Returns: The associated string if key is found and has valid
        format, default value otherwise./**
     * Get a string associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated string if key is found and has valid
     *         format, default value otherwise.
     *
     * @throws ConversionException is thrown if the key maps to an object that
     *         is not a String.
     */
    String getString(String key, String defaultValue);

    Get an array of strings associated with the given configuration key.
If the key doesn't map to an existing object an empty array is returned
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a String/List of Strings.
Returns: The associated string array if key is found./**
     * Get an array of strings associated with the given configuration key.
     * If the key doesn't map to an existing object an empty array is returned
     *
     * @param key The configuration key.
     * @return The associated string array if key is found.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a String/List of Strings.
     */
    String[] getStringArray(String key);

    Get a List of strings associated with the given configuration key.
If the key doesn't map to an existing object an empty List is returned.
Params: key – The configuration key.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a List.
Returns: The associated List./**
     * Get a List of strings associated with the given configuration key.
     * If the key doesn't map to an existing object an empty List is returned.
     *
     * @param key The configuration key.
     * @return The associated List.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a List.
     */
    List<Object> getList(String key);

    Get a List of strings associated with the given configuration key.
If the key doesn't map to an existing object, the default value
is returned.
Params: key – The configuration key.
defaultValue – The default value.
Throws: ConversionException – is thrown if the key maps to an
        object that is not a List.
Returns: The associated List of strings./**
     * Get a List of strings associated with the given configuration key.
     * If the key doesn't map to an existing object, the default value
     * is returned.
     *
     * @param key The configuration key.
     * @param defaultValue The default value.
     * @return The associated List of strings.
     *
     * @throws ConversionException is thrown if the key maps to an
     *         object that is not a List.
     */
    List<Object> getList(String key, List<?> defaultValue);
}
Author:	Commons Configuration team
Version:	$Id: Configuration.java 1534064 2013-10-21 08:44:33Z henning $
Params:	prefix – The prefix used to select the properties.
See Also:	SubsetConfiguration
Returns:	a subset configuration
Params:	key – the key whose presence in this configuration is to be tested
Returns:	`true` if the configuration contains a value for this key, `false` otherwise
Params:	key – property to retrieve
Returns:	the value to which this configuration maps the specified key, or null if the configuration contains no mapping for this key.
Params:	prefix – The prefix to test against.
See Also:	getKeys()
Returns:	An Iterator of keys that match the prefix.
Params:	key – The configuration key.
Throws:	ConversionException – is thrown if the key maps to an object that is not a String/List. IllegalArgumentException – if one of the tokens is malformed (does not contain an equals sign).
Returns:	The associated properties if key is found.
Params:	key – The configuration key. defaultValue – The default value.
Throws:	ConversionException – is thrown if the key maps to an object that is not a Boolean.
Returns:	The associated boolean.
/

commons-configuration/ commons-configuration/ 1.10/ org/apache/commons/configuration/Configuration.java
