/*
* Copyright (c) 2011. The Apache Software Foundation
*
* 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.hadoop.hbase.hbql.statement.args;
import org.apache.expreval.expr.ArgumentListTypeSignature;
import org.apache.expreval.expr.ExpressionProperty;
import org.apache.expreval.expr.node.GenericValue;
import org.apache.hadoop.hbase.hbql.client.HBqlException;
import java.io.Serializable;
import java.util.concurrent.atomic.AtomicBoolean;
public class DefaultArg extends ExpressionProperty implements Serializable {
private static final long serialVersionUID = 1L;
// We have to make value transient because Object is not serializable for RecordFilter
// We will compute it again on the server after reset is called
private Serializable value = null;
private AtomicBoolean atomicComputed = new AtomicBoolean(false);
public DefaultArg(final Class<? extends GenericValue> exprType, final GenericValue expr) throws HBqlException {
super(new ArgumentListTypeSignature(exprType), expr);
this.validate();
// This will force the type checking to happen
this.getDefaultValue();
}
private AtomicBoolean getAtomicComputed() {
return this.atomicComputed;
}
public void reset() {
this.getAtomicComputed().set(false);
this.value = null;
}
public Object getDefaultValue() throws HBqlException {
if (!this.getAtomicComputed().get()) {
synchronized (this) {
if (!this.getAtomicComputed().get()) {
// Type checking happens in this call, so we force it above in the constructor
this.value = (Serializable)this.evaluateConstant(0, false);
this.getAtomicComputed().set(true);
}
}
}
return this.value;
}
public String asString() {
return this.getGenericValue(0).asString();
}
}