root / org.gvsig.legend.aggregate / trunk / org.gvsig.legend.aggregate / org.gvsig.legend.aggregate.lib / org.gvsig.legend.aggregate.lib.impl / src / main / java / org / gvsig / legend / aggregate / lib / impl / operation / AvgOperation.java @ 1848
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package org.gvsig.legend.aggregate.lib.impl.operation; |
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import java.text.MessageFormat; |
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import org.apache.commons.lang3.StringUtils; |
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import org.gvsig.fmap.dal.feature.Feature; |
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import org.gvsig.legend.aggregate.lib.spi.AbstractOperation; |
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public class AvgOperation extends AbstractOperation { |
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private double avg = 0; |
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private int count = 0; |
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public AvgOperation() {
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super(
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"Average",
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"_Calculate_the_average_of_the_selected_attribute_for_the_grouped_features"
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); |
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} |
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@Override
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public boolean isAttributeRequiered() { |
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return true; |
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} |
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@Override
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public boolean isAditionalValueRequiered() { |
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return true; |
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} |
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@Override
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public void reset() { |
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avg = 0;
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count = 0;
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} |
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@Override
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public void perform(Feature feature) { |
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try {
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double value = feature.getDouble(this.getAttributeName()); |
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avg = ( avg * count + value ) / (count+1);
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count++; |
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} catch(Exception ex) { |
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} |
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} |
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@Override
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public Object getValue() { |
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return this.avg; |
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} |
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@Override
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public String format() { |
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if( StringUtils.isEmpty(this.getAditionalValue()) ) { |
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return super.format(); |
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} |
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try {
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return MessageFormat.format("{0,number,"+this.getAditionalValue()+"}", this.getValue()); |
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} catch(Exception ex) { |
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return super.format(); |
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} |
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} |
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} |