org.apache.commons.configuration2.beanutils.CombinedBeanDeclaration Maven / Gradle / Ivy
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Tools to assist in the reading of configuration/preferences files in
various formats
/*
* 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.configuration2.beanutils;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
*
* A special implementation of the {@code BeanDeclaration} interface which
* allows combining multiple {@code BeanDeclaration} objects.
*
*
* An instance of this class can be used if a bean is defined using multiple
* sources. For instance, there can be one definition with default values and
* one with actual values; if actual values are provided, they are used;
* otherwise, the default values apply.
*
*
* When constructing an instance an arbitrary number of child
* {@code BeanDeclaration} objects can be specified. The implementations of the
* {@code BeanDeclaration} methods implement a logical combination of the data
* returned by these child declarations. The order in which child declarations
* are added is relevant; first entries take precedence over later ones. The
* comments of the single methods explain in which way a combination of the
* child declarations is built.
*
*
* @version $Id: CombinedBeanDeclaration.java 1842194 2018-09-27 22:24:23Z ggregory $
* @since 2.0
*/
public class CombinedBeanDeclaration implements BeanDeclaration
{
/** A list with the child declarations. */
private final List childDeclarations;
/**
* Creates a new instance of {@code CombinedBeanDeclaration} and initializes
* it with the given child declarations.
*
* @param decl the child declarations
* @throws NullPointerException if the array with child declarations is
* null
*/
public CombinedBeanDeclaration(final BeanDeclaration... decl)
{
childDeclarations = new ArrayList<>(Arrays.asList(decl));
}
/**
* {@inheritDoc} This implementation iterates over the list of child
* declarations and asks them for a bean factory name. The first
* non-null value is returned. If none of the child declarations have
* a defined bean factory name, result is null.
*/
@Override
public String getBeanFactoryName()
{
for (final BeanDeclaration d : childDeclarations)
{
final String factoryName = d.getBeanFactoryName();
if (factoryName != null)
{
return factoryName;
}
}
return null;
}
/**
* {@inheritDoc} This implementation iterates over the list of child
* declarations and asks them for a bean factory parameter. The first
* non-null value is returned. If none of the child declarations have
* a defined bean factory parameter, result is null.
*/
@Override
public Object getBeanFactoryParameter()
{
for (final BeanDeclaration d : childDeclarations)
{
final Object factoryParam = d.getBeanFactoryParameter();
if (factoryParam != null)
{
return factoryParam;
}
}
return null;
}
/**
* {@inheritDoc} This implementation iterates over the list of child
* declarations and asks them for the bean class name. The first
* non-null value is returned. If none of the child declarations have
* a defined bean class, result is null.
*/
@Override
public String getBeanClassName()
{
for (final BeanDeclaration d : childDeclarations)
{
final String beanClassName = d.getBeanClassName();
if (beanClassName != null)
{
return beanClassName;
}
}
return null;
}
/**
* {@inheritDoc} This implementation creates a union of the properties
* returned by all child declarations. If a property is defined in multiple
* child declarations, the declaration that comes before in the list of
* children takes precedence.
*/
@Override
public Map getBeanProperties()
{
final Map result = new HashMap<>();
for (int i = childDeclarations.size() - 1; i >= 0; i--)
{
final Map props =
childDeclarations.get(i).getBeanProperties();
if (props != null)
{
result.putAll(props);
}
}
return result;
}
/**
* {@inheritDoc} This implementation creates a union of the nested bean
* declarations returned by all child declarations. If a complex property is
* defined in multiple child declarations, the declaration that comes before
* in the list of children takes precedence.
*/
@Override
public Map getNestedBeanDeclarations()
{
final Map result = new HashMap<>();
for (int i = childDeclarations.size() - 1; i >= 0; i--)
{
final Map decls =
childDeclarations.get(i).getNestedBeanDeclarations();
if (decls != null)
{
result.putAll(decls);
}
}
return result;
}
/**
* {@inheritDoc} This implementation iterates over the list of child
* declarations and asks them for constructor arguments. The first
* non-null and non empty collection is returned. If none of the
* child declarations provide constructor arguments, result is an empty
* collection.
*/
@Override
public Collection getConstructorArgs()
{
for (final BeanDeclaration d : childDeclarations)
{
final Collection args = d.getConstructorArgs();
if (args != null && !args.isEmpty())
{
return args;
}
}
return Collections.emptyList();
}
}