ConfigurationDeclaration.java

/*
 * 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.builder.combined;

import java.util.Set;

import org.apache.commons.configuration2.HierarchicalConfiguration;
import org.apache.commons.configuration2.beanutils.XMLBeanDeclaration;

/**
 * <p>
 * A specialized {@code BeanDeclaration} implementation that represents the declaration of a configuration source.
 * </p>
 * <p>
 * Instances of this class are able to extract all information about a configuration source from the configuration
 * definition file. The declaration of a configuration source is very similar to a bean declaration processed by
 * {@code XMLBeanDeclaration}. There are very few differences, for example some reserved attributes like {@code optional} and
 * {@code at}, and the fact that a bean factory is never needed.
 * </p>
 *
 * @since 2.0
 */
public class ConfigurationDeclaration extends XMLBeanDeclaration {
    /** Stores a reference to the associated configuration builder. */
    private final CombinedConfigurationBuilder configurationBuilder;

    /**
     * Creates a new instance of {@code ConfigurationDeclaration} and initializes it.
     *
     * @param builder the associated configuration builder
     * @param config the configuration this declaration is based onto
     */
    public ConfigurationDeclaration(final CombinedConfigurationBuilder builder, final HierarchicalConfiguration<?> config) {
        super(config);
        configurationBuilder = builder;
    }

    /**
     * Gets the value of the {@code at} attribute.
     *
     * @return the value of the {@code at} attribute (can be <strong>null</strong>)
     */
    public String getAt() {
        final String result = getConfiguration().getString(CombinedConfigurationBuilder.ATTR_AT_RES);
        return result == null ? getConfiguration().getString(CombinedConfigurationBuilder.ATTR_AT) : result;
    }

    /**
     * Gets the bean's class name. This implementation will always return <strong>null</strong>.
     *
     * @return the name of the bean's class
     */
    @Override
    public String getBeanClassName() {
        return null;
    }

    /**
     * Gets the name of the bean factory. For configuration source declarations always a reserved factory is used. This
     * factory's name is returned by this implementation.
     *
     * @return the name of the bean factory
     */
    @Override
    public String getBeanFactoryName() {
        return CombinedConfigurationBuilder.CONFIG_BEAN_FACTORY_NAME;
    }

    /**
     * Gets the associated configuration builder.
     *
     * @return the configuration builder
     */
    public CombinedConfigurationBuilder getConfigurationBuilder() {
        return configurationBuilder;
    }

    /**
     * Gets the name for the represented configuration source. The name is optional, so this method can return
     * <strong>null</strong>.
     *
     * @return the name of the associated configuration source or <strong>null</strong>
     */
    public String getName() {
        return getConfiguration().getString(CombinedConfigurationBuilder.ATTR_NAME);
    }

    /**
     * Gets a flag whether this configuration should always be created and added to the resulting combined configuration.
     * This flag is evaluated only for optional configurations whose normal creation has caused an error. If for such a
     * configuration the {@code forceCreate} attribute is set and the corresponding configuration provider supports this
     * mode, an empty configuration will be created and added to the resulting combined configuration.
     *
     * @return the value of the {@code forceCreate} attribute
     */
    public boolean isForceCreate() {
        return getConfiguration().getBoolean(CombinedConfigurationBuilder.ATTR_FORCECREATE, false);
    }

    /**
     * Gets a flag whether this is an optional configuration.
     *
     * @return a flag if this declaration points to an optional configuration
     */
    public boolean isOptional() {
        Boolean value = getConfiguration().getBoolean(CombinedConfigurationBuilder.ATTR_OPTIONAL_RES, null);
        if (value == null) {
            value = getConfiguration().getBoolean(CombinedConfigurationBuilder.ATTR_OPTIONAL, Boolean.FALSE);
        }
        return value.booleanValue();
    }

    /**
     * Returns a flag whether a builder with reloading support should be created. This may not be supported by all
     * configuration builder providers.
     *
     * @return a flag whether a reloading builder should be created
     */
    public boolean isReload() {
        return getConfiguration().getBoolean(CombinedConfigurationBuilder.ATTR_RELOAD, false);
    }

    /**
     * {@inheritDoc} This implementation checks for additional reserved attribute names. Note that in some cases the
     * presence of other attribute names determine whether a name is reserved or not. For instance, per default the
     * attribute {@code config-at} is reserved. However, if this attribute is not present, the attribute {@code at} is also
     * considered as a reserved attribute. (This is mainly done for dealing with legacy configuration files supported by
     * earlier versions of this library.)
     */
    @Override
    protected boolean isReservedAttributeName(final String name) {
        if (super.isReservedAttributeName(name)) {
            return true;
        }

        final Set<String> attributes = getAttributeNames();
        return CombinedConfigurationBuilder.ATTR_ATNAME.equals(name) && !attributes.contains(RESERVED_PREFIX + CombinedConfigurationBuilder.ATTR_ATNAME)
            || CombinedConfigurationBuilder.ATTR_OPTIONALNAME.equals(name)
                && !attributes.contains(RESERVED_PREFIX + CombinedConfigurationBuilder.ATTR_OPTIONALNAME);
    }
}