/*
* Copyright 2013 Cloudera Inc.
*
* 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
*
* 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 com.cloudera.cdk.morphline.stdlib;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import com.cloudera.cdk.morphline.api.Command;
import com.cloudera.cdk.morphline.api.CommandBuilder;
import com.cloudera.cdk.morphline.api.MorphlineCompilationException;
import com.cloudera.cdk.morphline.api.MorphlineContext;
import com.cloudera.cdk.morphline.api.Record;
import com.cloudera.cdk.morphline.base.AbstractCommand;
import com.typesafe.config.Config;
/**
* An If-Then-Else command consists of a chain of zero or more conditions commands, as well as a
* chain of zero or or more commands that are processed if all conditions succeed ("then commands"),
* as well as a chain of zero or more commands that are processed if one of the conditions fails
* ("else commands").
*
* If one of the commands in the "then" chain or "else" chain fails then the entire "if" command
* fails (and the remaining commands in the "then" or "else" branch are skipped).
*/
public final class IfThenElseBuilder implements CommandBuilder {
@Override
public Collection<String> getNames() {
return Collections.singletonList("if");
}
@Override
public Command build(Config config, Command parent, Command child, MorphlineContext context) {
return new IfThenElse(this, config, parent, child, context);
}
///////////////////////////////////////////////////////////////////////////////
// Nested classes:
///////////////////////////////////////////////////////////////////////////////
private static final class IfThenElse extends AbstractCommand {
private Command conditionChain;
private Command thenChain;
private Command elseChain;
public IfThenElse(CommandBuilder builder, Config config, Command parent, Command child, MorphlineContext context) {
super(builder, config, parent, child, context);
Command devNull = new DropRecordBuilder().build(null, this, null, context); // pipes into /dev/null
List<Command> conditions = buildCommandChain(config, "conditions", devNull, true);
if (conditions.size() == 0) {
throw new MorphlineCompilationException("Missing conditions", config);
} else {
this.conditionChain = conditions.get(0);
}
List<Command> thenCommands = buildCommandChain(config, "then", child, true);
if (thenCommands.size() > 0) {
this.thenChain = thenCommands.get(0);
}
List<Command> elseCommands = buildCommandChain(config, "else", child, true);
if (elseCommands.size() > 0) {
this.elseChain = elseCommands.get(0);
}
validateArguments();
}
protected List<Command> buildCommandChain(Config rootConfig, String configKey, Command finalChild, boolean ignoreNotifications) {
getConfigs().getConfigList(rootConfig, configKey, null);
return super.buildCommandChain(rootConfig, configKey, finalChild, ignoreNotifications);
}
@Override
protected void doNotify(Record notification) {
conditionChain.notify(notification);
if (thenChain != null) {
thenChain.notify(notification);
}
if (elseChain != null) {
elseChain.notify(notification);
}
super.doNotify(notification);
}
@Override
protected boolean doProcess(Record record) {
if (conditionChain.process(record)) {
if (thenChain != null) {
return thenChain.process(record);
}
} else {
if (elseChain != null) {
return elseChain.process(record);
}
}
return super.doProcess(record);
}
}
}