/*
* 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.beam.sdk.util.common;
import java.util.Observable;
import java.util.Observer;
/**
* An observer that gets notified when additional bytes are read and/or used.
*/
public abstract class ElementByteSizeObserver implements Observer {
private boolean isLazy = false;
private long totalSize = 0;
private double scalingFactor = 1.0;
public ElementByteSizeObserver() {}
/**
* Called to report element byte size.
*/
protected abstract void reportElementSize(long elementByteSize);
/**
* Sets byte counting for the current element as lazy. That is, the
* observer will get notified of the element's byte count only as
* element's pieces are being processed or iterated over.
*/
public void setLazy() {
isLazy = true;
}
/**
* Returns whether byte counting for the current element is lazy, that is,
* whether the observer gets notified of the element's byte count only as
* element's pieces are being processed or iterated over.
*/
public boolean getIsLazy() {
return isLazy;
}
/**
* Updates the observer with a context specified, but without an instance of
* the Observable.
*/
public void update(Object obj) {
update(null, obj);
}
/**
* Sets a multiplier to use on observed sizes.
*/
public void setScalingFactor(double scalingFactor) {
this.scalingFactor = scalingFactor;
}
@Override
public void update(Observable obs, Object obj) {
if (obj instanceof Long) {
totalSize += scalingFactor * (Long) obj;
} else if (obj instanceof Integer) {
totalSize += scalingFactor * (Integer) obj;
} else {
throw new AssertionError("unexpected parameter object");
}
}
/**
* Advances the observer to the next element. Adds the current total byte
* size to the counter, and prepares the observer for the next element.
*/
public void advance() {
reportElementSize(totalSize);
totalSize = 0;
isLazy = false;
}
}