AST构建Hibernat动态查询

一、效果

java 代码

public class HqlCompilerImplTest extends TestCase
{
    private IHqlCompiler compiler = new HqlCompilerImpl();

    public void test1()
    {
        Hql hql = compiler.compile("from User u where u.username = :username and u.age = :age order by u.username,u.age",
                new MapContext());
        assertEquals("from User u order by u.username,u.age", hql.getHql());
        assertEquals(0, hql.getParameters().length);
    }

    public void test2)
    {
        MapContext context = new MapContext();
        context.add("username", "ray");

        Hql hql = compiler
                .compile(
                        "from User u where u.username = :username and u.age = :age order by u.username,u.age",
                        context);

        assertEquals(
                "from User u where u.username = :username order by u.username,u.age",
                hql.getHql());
        assertEquals(1, hql.getParameters().length);
        assertEquals("username", hql.getParameters()[0].getName());
        assertEquals("ray", hql.getParameters()[0].getValue());
    }

    public void test3()
    {
        MapContext context = new MapContext();
        context.add("username", "ray");
        context.add("age", new Integer(10));

        Hql hql = compiler
        .compile(
                "from User u where u.username = :username and u.age = :age order by u.username,u.age",
                context);
        assertEquals(
                "from User u where (u.username = :username and u.age = :age) order by u.username,u.age",
                hql.getHql());
        assertEquals(2, hql.getParameters().length);
        assertEquals("username", hql.getParameters()[0].getName());
        assertEquals("ray", hql.getParameters()[0].getValue());
        assertEquals("age", hql.getParameters()[1].getName());
        assertEquals(new Integer(10), hql.getParameters()[1].getValue());
    }
}

二、基本接口

java 代码

package com.ayufox.framework.core;

/**
 * @author ray
 *
 */
public interface Context
{
    Object get(String name);
}

java 代码

package com.ayufox.framework.core.dao.hqlx;

import com.ayufox.framework.core.Context;
import com.ayufox.framework.core.dao.hql.Hql;

/**
 * @author ray
 *
 */
public interface IHqlCompiler
{
    Hql compile(String hql, Object ... values);

    Hql compile(String hql, Context context);
}

三、实现

java 代码

package com.ayufox.framework.core.dao.hqlx.ast;

import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import java.util.Collections;
import java.util.HashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.hql.ast.HqlParser;

import antlr.RecognitionException;
import antlr.TokenStreamException;
import antlr.collections.AST;

import com.ayufox.framework.core.Context;
import com.ayufox.framework.core.cache.Cache;
import com.ayufox.framework.core.cache.MapCache;
import com.ayufox.framework.core.dao.hql.Hql;
import com.ayufox.framework.core.dao.hqlx.DynamicMapContext;
import com.ayufox.framework.core.dao.hqlx.IHqlCompiler;
import com.ayufox.framework.core.dao.hqlx.IllegalSyntaxException;

/**
 * @author ray
 *
 */
public class HqlCompilerImpl implements IHqlCompiler
{
    private final static Log LOG = LogFactory.getLog(HqlCompilerImpl.class);

    private Cache astCache = new MapCache(Collections
            .synchronizedMap(new HashMap()));

    public void setAstCache(Cache astCache)
    {
        this.astCache = astCache;
    }

    /* (non-Javadoc)
     * @see com.konceptusa.framework.core.dao.hqlx.IHqlCompiler#compile(java.lang.String, java.lang.Object[])
     */
    public Hql compile(String hql, Object... values)
    {
        return compile(hql, new DynamicMapContext(values));
    }

    /* (non-Javadoc)
     * @see com.konceptusa.framework.core.dao.hqlx.IHqlCompiler#compile(java.lang.String, com.konceptusa.framework.core.Context)
     */
    public Hql compile(String hql, Context context)
    {
        if (hql == null || context == null)
        {
            throw new IllegalArgumentException("hql or context can't be null");
        }

        AST ast = getRootAST(hql);

        HqlCompileExecutor compilerContext = new HqlCompileExecutor(ast,
                context);
        return compilerContext.build();
    }

    protected AST getRootAST(String hql)
    {
        AST ast = (AST) this.astCache.get(hql);
        if (ast == null)
        {
            ast = createAST(hql);
            this.astCache.put(hql, ast);
            if (LOG.isDebugEnabled())
            {
                LOG.debug("get ast[" + ast + "] from cache for hql[" + hql
                        + "]");
            }
        }
        return ast;
    }

    private AST createAST(String hql)
    {
        HqlParser parser = HqlParser.getInstance(hql);
        try
        {
            parser.statement();
        }
        catch (RecognitionException e)
        {
            throw new IllegalSyntaxException(e);
        }
        catch (TokenStreamException e)
        {
            throw new IllegalSyntaxException(e);
        }
        AST ast = parser.getAST();
        parser.getParseErrorHandler().throwQueryException();
        if (LOG.isDebugEnabled())
        {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            parser.showAst(ast, new PrintStream(baos));
            LOG.debug("AST:" + new String(baos.toByteArray()));
        }
        return ast;
    }
}