com.redhat.lightblue.assoc.ep.AssociationQuery Maven / Gradle / Ivy

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package com.redhat.lightblue.assoc.ep;

import java.util.List;
import java.util.ArrayList;

import com.redhat.lightblue.metadata.CompositeMetadata;
import com.redhat.lightblue.metadata.ResolvedReferenceField;

import com.redhat.lightblue.assoc.BoundObject;
import com.redhat.lightblue.assoc.Conjunct;
import com.redhat.lightblue.assoc.RewriteQuery;
import com.redhat.lightblue.assoc.QueryFieldInfo;
import com.redhat.lightblue.assoc.AnalyzeQuery;

import com.redhat.lightblue.mindex.GetIndexKeySpec;
import com.redhat.lightblue.mindex.KeySpec;

import com.redhat.lightblue.query.QueryExpression;

/**
 * Keeps an edge query along with its binding information.
 */
public class AssociationQuery {

    private final List fieldBindings = new ArrayList<>();
    private final QueryExpression query;
    private final ResolvedReferenceField reference;
    // If non-null, query is either always true or always false
    private final Boolean always;
    private final List qfi;
    // In-memory index key spec
    private final KeySpec keySpec;

    public AssociationQuery(CompositeMetadata root,
                            CompositeMetadata currentEntity,
                            ResolvedReferenceField reference,
                            List conjuncts) {
        this.reference = reference;
        RewriteQuery rewriter = new RewriteQuery(root, currentEntity);
        List queries = new ArrayList<>(conjuncts.size());
        int numTrue=0;
        int numFalse=0;
        qfi=new ArrayList<>();
        for (Conjunct c : conjuncts) {
            RewriteQuery.RewriteQueryResult result = rewriter.rewriteQuery(c.getClause(), c.getFieldInfo());
            if(result.query instanceof RewriteQuery.TruePH) {
                // Don't add this into the query
                numTrue++;
            } else if(result.query instanceof RewriteQuery.FalsePH) {
                numFalse++;
            } else {
                queries.add(result.query);
                // Analyze the query as if it is a root entity query
                AnalyzeQuery aq=new AnalyzeQuery(currentEntity,null);
                aq.iterate(result.query);
                qfi.addAll(aq.getFieldInfo());
           }
            fieldBindings.addAll(result.bindings);
        }
        if(queries.isEmpty()) {
            query=null;
            if(numTrue>0&&numFalse==0) {
                always=Boolean.TRUE;
            } else if(numFalse>0) {
                always=Boolean.FALSE;
            } else {
                always=null;
            }
            keySpec=null;
        } else {
            query = Searches.and(queries);
            GetIndexKeySpec giks=new GetIndexKeySpec(qfi);
            keySpec=giks.iterate(query);
            always=null;
        }
    }

    public KeySpec getIndexKeySpec() {
        return keySpec;
    }
    
    public List getQueryFieldInfo() {
        return qfi;
    }

    public Boolean getAlways() {
        return always;
    }

    public boolean isAlwaysTrue() {
        return always!=null&&always;
    }

    public boolean isAlwaysFalse() {
        return always!=null&&!always;
    }

    public QueryExpression getQuery() {
        return query;
    }

    public List getFieldBindings() {
        return fieldBindings;
    }

    /**
     * Returns the reference field from the parent entity to current entity
     */
    public ResolvedReferenceField getReference() {
        return reference;
    }

    @Override
    public String toString() {
        return query.toString() + " [ " + fieldBindings + " ]";
    }
}