org.apache.flink.table.functions.FunctionContext Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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,
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* See the License for the specific language governing permissions and
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*/
package org.apache.flink.table.functions;
import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.api.common.ExecutionConfig.GlobalJobParameters;
import org.apache.flink.api.common.externalresource.ExternalResourceInfo;
import org.apache.flink.api.common.functions.Function;
import org.apache.flink.api.common.functions.RuntimeContext;
import org.apache.flink.metrics.MetricGroup;
import java.io.File;
import java.util.Set;
/**
* A {@link FunctionContext} allows to obtain global runtime information about the context in which
* the user-defined function is executed.
*
* The information includes the metric group, distributed cache files, and global job parameters.
*/
@PublicEvolving
public class FunctionContext {
private RuntimeContext context;
/**
* Wraps the underlying {@link RuntimeContext}.
*
* @param context the runtime context in which Flink's {@link Function} is executed.
*/
public FunctionContext(RuntimeContext context) {
this.context = context;
}
/**
* Returns the metric group for this parallel subtask.
*
* @return metric group for this parallel subtask.
*/
public MetricGroup getMetricGroup() {
return context.getMetricGroup();
}
/**
* Gets the local temporary file copy of a distributed cache files.
*
* @param name distributed cache file name
* @return local temporary file copy of a distributed cache file.
*/
public File getCachedFile(String name) {
return context.getDistributedCache().getFile(name);
}
/**
* Gets the global job parameter value associated with the given key as a string.
*
* @param key key pointing to the associated value
* @param defaultValue default value which is returned in case global job parameter is null or
* there is no value associated with the given key
* @return (default) value associated with the given key
*/
public String getJobParameter(String key, String defaultValue) {
final GlobalJobParameters conf = context.getExecutionConfig().getGlobalJobParameters();
if (conf != null) {
return conf.toMap().getOrDefault(key, defaultValue);
}
return defaultValue;
}
/** Get the external resource information. */
public Set getExternalResourceInfos(String resourceName) {
return context.getExternalResourceInfos(resourceName);
}
}