com.mysema.query.collections.AbstractColQuery Maven / Gradle / Ivy

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/*
 * Copyright (c) 2010 Mysema Ltd.
 * All rights reserved.
 *
 */
package com.mysema.query.collections;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.mysema.commons.lang.CloseableIterator;
import com.mysema.commons.lang.IteratorAdapter;
import com.mysema.query.JoinType;
import com.mysema.query.QueryException;
import com.mysema.query.QueryMetadata;
import com.mysema.query.SearchResults;
import com.mysema.query.support.ProjectableQuery;
import com.mysema.query.types.ArrayConstructorExpression;
import com.mysema.query.types.CollectionExpression;
import com.mysema.query.types.Expression;
import com.mysema.query.types.MapExpression;
import com.mysema.query.types.OperationImpl;
import com.mysema.query.types.Ops;
import com.mysema.query.types.Path;

/**
 * AbstractColQuery provides a base class for Collection query implementations.
 * Extend it like this
 *
 *  * public class MyType extends AbstractColQuery<MyType>{
 *   ...
 * }
 * 
 *
 * @see ColQuery
 *
 * @author tiwe
 */
public abstract class AbstractColQuery>  extends ProjectableQuery {

    private final Map, Iterable> iterables = new HashMap, Iterable>();

    private final QueryEngine queryEngine;

    @SuppressWarnings("unchecked")
    public AbstractColQuery(QueryMetadata metadata, QueryEngine queryEngine) {
        super(new ColQueryMixin(metadata));
        this.queryMixin.setSelf((Q) this);
        this.queryEngine = queryEngine;
    }

    @Override
    public long count() {
        try {
            return queryEngine.count(getMetadata(), iterables);
        } catch (Exception e) {
            throw new QueryException(e.getMessage(), e);
        }finally{
            reset();
        }
    }

    @Override
    public boolean exists(){
        try {
            return queryEngine.exists(getMetadata(), iterables);
        } catch (Exception e) {
            throw new QueryException(e.getMessage(), e);
        }finally{
            reset();
        }
    }

    private  Expression createAlias(CollectionExpression target, Path alias){
        return OperationImpl.create(alias.getType(), Ops.ALIAS, target, alias);
    }

    private  Expression createAlias(MapExpression target, Path alias){
        return OperationImpl.create(alias.getType(), Ops.ALIAS, target, alias);
    }

    @SuppressWarnings("unchecked")
    public  Q from(Path entity, Iterable col) {
        iterables.put(entity, col);
        getMetadata().addJoin(JoinType.DEFAULT, entity);
        return (Q)this;
    }
    
    @SuppressWarnings("unchecked")
    public  Q bind(Path entity, Iterable col) {
        iterables.put(entity, col);
        return (Q)this;
    }

    public abstract QueryMetadata getMetadata();

    protected QueryEngine getQueryEngine(){
        return queryEngine;
    }

    @SuppressWarnings("unchecked")
    public  Q innerJoin(CollectionExpression target, Path
 alias) {
        getMetadata().addJoin(JoinType.INNERJOIN, createAlias(target, alias));
        return (Q)this;
    }

    @SuppressWarnings("unchecked")
    public 
 Q innerJoin(MapExpression target, Path
 alias) {
        getMetadata().addJoin(JoinType.INNERJOIN, createAlias(target, alias));
        return (Q)this;
    }

    @Override
    public CloseableIterator iterate(Expression[] args) {
        return iterate(new ArrayConstructorExpression