/*
* 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.openjpa.kernel.exps;
import org.apache.openjpa.kernel.StoreContext;
/**
* Take the substring of a string.
*
* @author Abe White
*/
class Substring
extends Val {
private final Val _val;
private final Val _args;
/**
* Constructor. Provide value to take substring of and arguments to
* substring method.
*/
public Substring(Val val, Val args) {
_val = val;
_args = args;
}
public Class getType() {
return String.class;
}
public void setImplicitType(Class type) {
}
protected Object eval(Object candidate, Object orig,
StoreContext ctx, Object[] params) {
Object str = _val.eval(candidate, orig, ctx, params);
Object arg = _args.eval(candidate, orig, ctx, params);
if (arg instanceof Object[]) {
Object[] args = (Object[]) arg;
int start = ((Number) args[0]).intValue() - 1;
int length = ((Number) args[1]).intValue();
String string = str == null ? "" : str.toString();
return string.substring(start, Math.min(start + length, string.length()));
}
return str.toString().substring(((Number) arg).intValue() - 1);
}
public void acceptVisit(ExpressionVisitor visitor) {
visitor.enter(this);
_val.acceptVisit(visitor);
_args.acceptVisit(visitor);
visitor.exit(this);
}
}