configjsr/src/main/java/org/apache/tamaya/jsr382/JavaConfigSource.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.tamaya.jsr382;

import org.apache.tamaya.spi.PropertySource;
import org.apache.tamaya.spi.PropertyValue;

import javax.config.spi.ConfigSource;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.function.Consumer;

/**
 * Javaconfig {@link ConfigSource} implementation that wraps a {@link PropertySource} instance.
 */
public class JavaConfigSource implements ConfigSource {

    private PropertySource delegate;

    public JavaConfigSource(PropertySource propertySource) {
        this.delegate = Objects.requireNonNull(propertySource);
    }

    public PropertySource getPropertySource() {
        return this.delegate;
    }

    @Override
    public int getOrdinal() {
        return delegate.getOrdinal();
    }

    @Override
    public String getName() {
        return delegate.getName();
    }

    @Override
    public String getValue(String key) {
        PropertyValue value = delegate.get(key);
        if (value != null) {
            return value.getValue();
        }
        return null;
    }

    @Override
    public Map<String, String> getProperties() {
        return toMap(delegate.getProperties());
    }

    private Map<String, String> toMap(Map<String, PropertyValue> properties) {
        Map<String, String> valueMap = new HashMap<>(properties.size());
        for (Map.Entry<String, PropertyValue> en : properties.entrySet()) {
            if (en.getValue().getValue() != null) {
                valueMap.put(en.getKey(), en.getValue().getValue());
            }
        }
        return valueMap;
    }

    /**
     * The callback should get invoked if an attribute change got detected inside the ConfigSource.
     *
     * @param callback will be set by the {@link javax.config.Config} after this
     *                 {@code ConfigSource} got created and before any configured values
     *                 get served.
     * @return ChangeSupport informing the {@link javax.config.Config} implementation about support for changes by this source
     * @see ChangeSupport
     */
    // TODO implement change support in Tamaya
    public ChangeSupport setOnAttributeChange(Consumer<Set<String>> callback) {
        switch (delegate.getChangeSupport()) {
            case SUPPORTED:
                delegate.addChangeListener((s, ps) -> {
                    callback.accept(s);
                });
                return ChangeSupport.SUPPORTED;
            case IMMUTABLE:
                return ChangeSupport.IMMUTABLE;
            case UNSUPPORTED:
            default:
                return ChangeSupport.UNSUPPORTED;
        }
    }

    @Override
    public String toString() {
        return "JavaConfigSource{" +
                "delegate=" + delegate +
                '}';
    }
}