org.apache.openjpa.kernel.exps.BindVariableAndExpression Maven / Gradle / Ivy
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* 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
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* 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 java.util.Collection;
import java.util.Iterator;
import org.apache.openjpa.kernel.StoreContext;
/**
* Any contains(var) expression must be followed by at least one
* AND clause using the variable 'var'. This expression type represents
* one of those and AND clauses. It is responsible for evaluating the
* right subexpression for every possible value of the variable.
*
* @author Abe White
*/
class BindVariableAndExpression
extends AndExpression {
private static final long serialVersionUID = 1L;
/**
* Constructor. Provide expression binding the variable and the
* expression it is AND'd with.
*/
public BindVariableAndExpression(BindVariableExpression var, Exp exp) {
super(var, exp);
}
@Override
protected boolean eval(Object candidate, Object orig,
StoreContext ctx, Object[] params) {
// execute the tree for every element in the variable's collection;
// the variable is aliased to the current element before each
// iteration so that variable paths within the tree can
// use the current value; the expression is true if true for any
// value of the collection
// if the collection is empty it cannot contain any variable
BindVariableExpression bind = (BindVariableExpression)
getExpression1();
Collection vals = bind.getVariableValues(candidate, orig, ctx,
params);
if (vals == null || vals.isEmpty())
return false;
// the subtree is true if true for any variable in the collection
BoundVariable var = bind.getVariable();
for (Iterator itr = vals.iterator(); itr.hasNext();) {
if (!var.setValue(itr.next()))
continue;
if (getExpression2().evaluate(candidate, orig, ctx, params))
return true;
}
return false;
}
@Override
protected boolean eval(Collection candidates, StoreContext ctx,
Object[] params) {
if (candidates == null || candidates.isEmpty())
return false;
Object obj = candidates.iterator().next();
return eval(obj, obj, ctx, params);
}
}