org.springframework.context.support.DelegatingMessageSource.java Source code

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Here is the source code for org.springframework.context.support.DelegatingMessageSource.java

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/*
 * Copyright 2002-2017 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.context.support;

import java.util.Locale;

import org.springframework.context.HierarchicalMessageSource;
import org.springframework.context.MessageSource;
import org.springframework.context.MessageSourceResolvable;
import org.springframework.context.NoSuchMessageException;
import org.springframework.lang.Nullable;

/**
 * Empty {@link MessageSource} that delegates all calls to the parent MessageSource.
 * If no parent is available, it simply won't resolve any message.
 *
 * <p>Used as placeholder by AbstractApplicationContext, if the context doesn't
 * define its own MessageSource. Not intended for direct use in applications.
 *
 * @author Juergen Hoeller
 * @since 1.1.5
 * @see AbstractApplicationContext
 */
public class DelegatingMessageSource extends MessageSourceSupport implements HierarchicalMessageSource {

    @Nullable
    private MessageSource parentMessageSource;

    @Override
    public void setParentMessageSource(@Nullable MessageSource parent) {
        this.parentMessageSource = parent;
    }

    @Override
    @Nullable
    public MessageSource getParentMessageSource() {
        return this.parentMessageSource;
    }

    @Override
    @Nullable
    public String getMessage(String code, @Nullable Object[] args, @Nullable String defaultMessage, Locale locale) {
        if (this.parentMessageSource != null) {
            return this.parentMessageSource.getMessage(code, args, defaultMessage, locale);
        } else if (defaultMessage != null) {
            return renderDefaultMessage(defaultMessage, args, locale);
        } else {
            return null;
        }
    }

    @Override
    public String getMessage(String code, @Nullable Object[] args, Locale locale) throws NoSuchMessageException {
        if (this.parentMessageSource != null) {
            return this.parentMessageSource.getMessage(code, args, locale);
        } else {
            throw new NoSuchMessageException(code, locale);
        }
    }

    @Override
    public String getMessage(MessageSourceResolvable resolvable, Locale locale) throws NoSuchMessageException {
        if (this.parentMessageSource != null) {
            return this.parentMessageSource.getMessage(resolvable, locale);
        } else {
            if (resolvable.getDefaultMessage() != null) {
                return renderDefaultMessage(resolvable.getDefaultMessage(), resolvable.getArguments(), locale);
            }
            String[] codes = resolvable.getCodes();
            String code = (codes != null && codes.length > 0 ? codes[0] : "");
            throw new NoSuchMessageException(code, locale);
        }
    }

    @Override
    public String toString() {
        return this.parentMessageSource != null ? this.parentMessageSource.toString() : "Empty MessageSource";
    }

}