org.springframework.core.env.PropertySourcesPropertyResolver.java Source code

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Here is the source code for org.springframework.core.env.PropertySourcesPropertyResolver.java

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/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed 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
 *
 *      https://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.springframework.core.env;

import org.springframework.lang.Nullable;

/**
 * {@link PropertyResolver} implementation that resolves property values against
 * an underlying set of {@link PropertySources}.
 *
 * @author Chris Beams
 * @author Juergen Hoeller
 * @since 3.1
 * @see PropertySource
 * @see PropertySources
 * @see AbstractEnvironment
 */
public class PropertySourcesPropertyResolver extends AbstractPropertyResolver {

    @Nullable
    private final PropertySources propertySources;

    /**
     * Create a new resolver against the given property sources.
     * @param propertySources the set of {@link PropertySource} objects to use
     */
    public PropertySourcesPropertyResolver(@Nullable PropertySources propertySources) {
        this.propertySources = propertySources;
    }

    @Override
    public boolean containsProperty(String key) {
        if (this.propertySources != null) {
            for (PropertySource<?> propertySource : this.propertySources) {
                if (propertySource.containsProperty(key)) {
                    return true;
                }
            }
        }
        return false;
    }

    @Override
    @Nullable
    public String getProperty(String key) {
        return getProperty(key, String.class, true);
    }

    @Override
    @Nullable
    public <T> T getProperty(String key, Class<T> targetValueType) {
        return getProperty(key, targetValueType, true);
    }

    @Override
    @Nullable
    protected String getPropertyAsRawString(String key) {
        return getProperty(key, String.class, false);
    }

    @Nullable
    protected <T> T getProperty(String key, Class<T> targetValueType, boolean resolveNestedPlaceholders) {
        if (this.propertySources != null) {
            for (PropertySource<?> propertySource : this.propertySources) {
                if (logger.isTraceEnabled()) {
                    logger.trace(
                            "Searching for key '" + key + "' in PropertySource '" + propertySource.getName() + "'");
                }
                Object value = propertySource.getProperty(key);
                if (value != null) {
                    if (resolveNestedPlaceholders && value instanceof String) {
                        value = resolveNestedPlaceholders((String) value);
                    }
                    logKeyFound(key, propertySource, value);
                    return convertValueIfNecessary(value, targetValueType);
                }
            }
        }
        if (logger.isTraceEnabled()) {
            logger.trace("Could not find key '" + key + "' in any property source");
        }
        return null;
    }

    /**
     * Log the given key as found in the given {@link PropertySource}, resulting in
     * the given value.
     * <p>The default implementation writes a debug log message with key and source.
     * As of 4.3.3, this does not log the value anymore in order to avoid accidental
     * logging of sensitive settings. Subclasses may override this method to change
     * the log level and/or log message, including the property's value if desired.
     * @param key the key found
     * @param propertySource the {@code PropertySource} that the key has been found in
     * @param value the corresponding value
     * @since 4.3.1
     */
    protected void logKeyFound(String key, PropertySource<?> propertySource, Object value) {
        if (logger.isDebugEnabled()) {
            logger.debug("Found key '" + key + "' in PropertySource '" + propertySource.getName()
                    + "' with value of type " + value.getClass().getSimpleName());
        }
    }

}