stream.flow.If Maven / Gradle / Ivy
/*
* streams library
*
* Copyright (C) 2011-2012 by Christian Bockermann, Hendrik Blom
*
* streams is a library, API and runtime environment for processing high
* volume data streams. It is composed of three submodules "stream-api",
* "stream-core" and "stream-runtime".
*
* The streams library (and its submodules) is free software: you can
* redistribute it and/or modify it under the terms of the
* GNU Affero General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* The stream.ai library (and its submodules) is distributed in the hope
* that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*/
package stream.flow;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import stream.ProcessorList;
import stream.annotations.Description;
import stream.annotations.Parameter;
import stream.data.Data;
import stream.expressions.Expression;
import stream.expressions.ExpressionCompiler;
/**
* @author chris
*
*/
@Description(group = "Data Stream.Flow")
public class If extends ProcessorList {
static Logger log = LoggerFactory.getLogger(If.class);
Expression condition;
/**
* @return the condition
*/
public String getCondition() {
if (condition == null)
return "";
return condition.toString();
}
/**
* @param condition
* the condition to set
*/
@Parameter(name = "condition", required = false)
public void setCondition(String condition) {
try {
if (condition == null || "".equals(condition.trim())) {
condition = null;
return;
}
this.condition = ExpressionCompiler.parse(condition);
} catch (Exception e) {
throw new RuntimeException(e.getMessage());
}
}
public boolean matches(Data item) {
return (condition == null || condition.matches(context, item));
}
/**
* @see stream.ProcessorList#process(stream.data.Data)
*/
@Override
public Data process(Data input) {
if (matches(input)) {
log.debug("processing item {}", input);
return super.process(input);
} else {
log.debug("skipping item {}", input);
return input;
}
}
}