/*
* Copyright 2013 Bazaarvoice, 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.bazaarvoice.jolt.cardinality;
import com.bazaarvoice.jolt.common.WalkedPath;
import com.bazaarvoice.jolt.common.pathelement.AtPathElement;
import com.bazaarvoice.jolt.common.pathelement.LiteralPathElement;
import com.bazaarvoice.jolt.common.pathelement.MatchablePathElement;
import com.bazaarvoice.jolt.common.pathelement.PathElement;
import com.bazaarvoice.jolt.common.pathelement.StarAllPathElement;
import com.bazaarvoice.jolt.common.pathelement.StarRegexPathElement;
import com.bazaarvoice.jolt.common.pathelement.StarSinglePathElement;
import com.bazaarvoice.jolt.exception.SpecException;
import org.apache.commons.lang.StringUtils;
import java.util.Arrays;
import java.util.List;
/**
* A Spec Object represents a single line from the JSON Cardinality Spec.
*
* At a minimum a single Spec has :
* Raw LHS spec value
* Some kind of PathElement (based off that raw LHS value)
*
* Additionally there are 2 distinct subclasses of the base Spec
* CardinalityLeafSpec : where the RHS is either "ONE" or "MANY"
* CardinalityCompositeSpec : where the RHS is a map of children Specs
*
* The tree structure of formed by the CompositeSpecs is what is used during the transform
* to do the parallel tree walk with the input data tree.
*
* During the parallel tree walk, a Path<Literal PathElements> is maintained, and used when
* a tree walk encounters a leaf spec.
*/
public abstract class CardinalitySpec {
// The processed key from the Json config
protected final MatchablePathElement pathElement;
public CardinalitySpec( String rawJsonKey ) {
List<PathElement> pathElements = parse( rawJsonKey );
if ( pathElements.size() != 1 ){
throw new SpecException( "CardinalityTransform invalid LHS:" + rawJsonKey + " can not contain '.'" );
}
PathElement pe = pathElements.get( 0 );
if ( ! ( pe instanceof MatchablePathElement ) ) {
throw new SpecException( "Spec LHS key=" + rawJsonKey + " is not a valid LHS key." );
}
this.pathElement = (MatchablePathElement) pe;
}
// once all the cardinalitytransform specific logic is extracted.
public static List<PathElement> parse( String key ) {
if ( key.contains("@") ) {
return Arrays.<PathElement>asList( new AtPathElement( key ) );
}
else if ( "*".equals( key ) ) {
return Arrays.<PathElement>asList( new StarAllPathElement( key ) );
}
else if ( key.contains( "*" ) ) {
if ( StringUtils.countMatches( key, "*" ) == 1 ) {
return Arrays.<PathElement>asList( new StarSinglePathElement( key ) );
}
else {
return Arrays.<PathElement>asList( new StarRegexPathElement( key ) );
}
}
else {
return Arrays.<PathElement>asList( new LiteralPathElement( key ) );
}
}
/**
* This is the main recursive method of the CardinalityTransform parallel "spec" and "input" tree walk.
*
* It should return true if this Spec object was able to successfully apply itself given the
* inputKey and input object.
*
* In the context of the CardinalityTransform parallel treewalk, if this method returns a non-null Object,
* the assumption is that no other sibling Cardinality specs need to look at this particular input key.
*
* @return true if this this spec "handles" the inputkey such that no sibling specs need to see it
*/
public abstract boolean apply( String inputKey, Object input, WalkedPath walkedPath, Object parentContainer );
}