package org.apache.lucene.expressions;
/*
* 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.
*/
import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.queries.function.FunctionValues;
import org.apache.lucene.queries.function.ValueSource;
import org.apache.lucene.search.SortField;
/**
* A {@link ValueSource} which evaluates a {@link Expression} given the context of an {@link Bindings}.
*/
@SuppressWarnings({"rawtypes", "unchecked"})
final class ExpressionValueSource extends ValueSource {
final ValueSource variables[];
final Expression expression;
final boolean needsScores;
ExpressionValueSource(Bindings bindings, Expression expression) {
if (bindings == null) throw new NullPointerException();
if (expression == null) throw new NullPointerException();
this.expression = expression;
variables = new ValueSource[expression.variables.length];
boolean needsScores = false;
for (int i = 0; i < variables.length; i++) {
ValueSource source = bindings.getValueSource(expression.variables[i]);
if (source instanceof ScoreValueSource) {
needsScores = true;
} else if (source instanceof ExpressionValueSource) {
if (((ExpressionValueSource)source).needsScores()) {
needsScores = true;
}
} else if (source == null) {
throw new RuntimeException("Internal error. Variable (" + expression.variables[i] + ") does not exist.");
}
variables[i] = source;
}
this.needsScores = needsScores;
}
@Override
public FunctionValues getValues(Map context, AtomicReaderContext readerContext) throws IOException {
Map<String, FunctionValues> valuesCache = (Map<String, FunctionValues>)context.get("valuesCache");
if (valuesCache == null) {
valuesCache = new HashMap<String, FunctionValues>();
context = new HashMap(context);
context.put("valuesCache", valuesCache);
}
FunctionValues[] externalValues = new FunctionValues[expression.variables.length];
for (int i = 0; i < variables.length; ++i) {
String externalName = expression.variables[i];
FunctionValues values = valuesCache.get(externalName);
if (values == null) {
values = variables[i].getValues(context, readerContext);
if (values == null) {
throw new RuntimeException("Internal error. External (" + externalName + ") does not exist.");
}
valuesCache.put(externalName, values);
}
externalValues[i] = values;
}
return new ExpressionFunctionValues(this, expression, externalValues);
}
@Override
public SortField getSortField(boolean reverse) {
return new ExpressionSortField(expression.sourceText, this, reverse);
}
@Override
public String description() {
return "expr(" + expression.sourceText + ")";
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result
+ ((expression == null) ? 0 : expression.hashCode());
result = prime * result + (needsScores ? 1231 : 1237);
result = prime * result + Arrays.hashCode(variables);
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
ExpressionValueSource other = (ExpressionValueSource) obj;
if (expression == null) {
if (other.expression != null) {
return false;
}
} else if (!expression.equals(other.expression)) {
return false;
}
if (needsScores != other.needsScores) {
return false;
}
if (!Arrays.equals(variables, other.variables)) {
return false;
}
return true;
}
boolean needsScores() {
return needsScores;
}
}