com.dexcoder.dal.batis.xml.ForEachSqlNode Maven / Gradle / Ivy

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package com.dexcoder.dal.batis.xml;

import java.util.Map;

import com.dexcoder.dal.batis.build.Configuration;
import com.dexcoder.dal.batis.build.DynamicContext;
import com.dexcoder.dal.batis.ognl.ExpressionEvaluator;
import com.dexcoder.dal.handler.GenericTokenParser;
import com.dexcoder.dal.handler.TokenHandler;

/**
 * Created by liyd on 2015-11-30.
 */
public class ForEachSqlNode implements SqlNode {
    public static final String  ITEM_PREFIX = "__frch_";

    private ExpressionEvaluator evaluator;
    private String              collectionExpression;
    private SqlNode             contents;
    private String              open;
    private String              close;
    private String              separator;
    private String              item;
    private String              index;

    //    private Configuration       configuration;

    public ForEachSqlNode(Configuration configuration, SqlNode contents, String collectionExpression, String index,
                          String item, String open, String close, String separator) {
        this.evaluator = new ExpressionEvaluator();
        this.collectionExpression = collectionExpression;
        this.contents = contents;
        this.open = open;
        this.close = close;
        this.separator = separator;
        this.index = index;
        this.item = item;
        //        this.configuration = configuration;
    }

    public boolean apply(DynamicContext context) {
        Map bindings = context.getBindings();
        final Iterable iterable = evaluator.evaluateIterable(collectionExpression, bindings);
        if (!iterable.iterator().hasNext()) {
            return true;
        }
        boolean first = true;
        applyOpen(context);
        int i = 0;
        for (Object o : iterable) {
            DynamicContext oldContext = context;
            if (first) {
                context = new PrefixedContext(context, "");
            } else if (separator != null) {
                context = new PrefixedContext(context, separator);
            } else {
                context = new PrefixedContext(context, "");
            }
            int uniqueNumber = context.getUniqueNumber();
            // Issue #709
            if (o instanceof Map.Entry) {
                @SuppressWarnings("unchecked")
                Map.Entry mapEntry = (Map.Entry) o;
                applyIndex(context, mapEntry.getKey(), uniqueNumber);
                applyItem(context, mapEntry.getValue(), uniqueNumber);
            } else {
                applyIndex(context, i, uniqueNumber);
                applyItem(context, o, uniqueNumber);
            }
            contents.apply(new FilteredDynamicContext(context, index, item, uniqueNumber));
            if (first) {
                first = !((PrefixedContext) context).isPrefixApplied();
            }
            context = oldContext;
            i++;
        }
        applyClose(context);
        return true;
    }

    private void applyIndex(DynamicContext context, Object o, int i) {
        if (index != null) {
            context.bind(index, o);
            context.bind(itemizeItem(index, i), o);
        }
    }

    private void applyItem(DynamicContext context, Object o, int i) {
        if (item != null) {
            context.bind(item, o);
            context.bind(itemizeItem(item, i), o);
        }
    }

    private void applyOpen(DynamicContext context) {
        if (open != null) {
            context.appendSql(open);
        }
    }

    private void applyClose(DynamicContext context) {
        if (close != null) {
            context.appendSql(close);
        }
    }

    private static String itemizeItem(String item, int i) {
        return new StringBuilder(ITEM_PREFIX).append(item).append("_").append(i).toString();
    }

    private static class FilteredDynamicContext extends DynamicContext {
        private DynamicContext delegate;
        private int            index;
        private String         itemIndex;
        private String         item;

        public FilteredDynamicContext(DynamicContext delegate, String itemIndex, String item, int i) {
            super(null);
            this.delegate = delegate;
            this.index = i;
            this.itemIndex = itemIndex;
            this.item = item;
        }

        @Override
        public Map getBindings() {
            return delegate.getBindings();
        }

        @Override
        public void bind(String name, Object value) {
            delegate.bind(name, value);
        }

        @Override
        public String getSql() {
            return delegate.getSql();
        }

        @Override
        public void appendSql(String sql) {
            GenericTokenParser parser = new GenericTokenParser("#{", "}", new TokenHandler() {
                public String handleToken(String content) {
                    String newContent = content
                        .replaceFirst("^\\s*" + item + "(?![^.,:\\s])", itemizeItem(item, index));
                    if (itemIndex != null && newContent.equals(content)) {
                        newContent = content.replaceFirst("^\\s*" + itemIndex + "(?![^.,:\\s])",
                            itemizeItem(itemIndex, index));
                    }
                    return new StringBuilder("#{").append(newContent).append("}").toString();
                }
            });

            delegate.appendSql(parser.parse(sql));
        }

        @Override
        public int getUniqueNumber() {
            return delegate.getUniqueNumber();
        }

    }

    private class PrefixedContext extends DynamicContext {
        private DynamicContext delegate;
        private String         prefix;
        private boolean        prefixApplied;

        public PrefixedContext(DynamicContext delegate, String prefix) {
            super(null);
            this.delegate = delegate;
            this.prefix = prefix;
            this.prefixApplied = false;
        }

        public boolean isPrefixApplied() {
            return prefixApplied;
        }

        @Override
        public Map getBindings() {
            return delegate.getBindings();
        }

        @Override
        public void bind(String name, Object value) {
            delegate.bind(name, value);
        }

        @Override
        public void appendSql(String sql) {
            if (!prefixApplied && sql != null && sql.trim().length() > 0) {
                delegate.appendSql(prefix);
                prefixApplied = true;
            }
            delegate.appendSql(sql);
        }

        @Override
        public String getSql() {
            return delegate.getSql();
        }

        @Override
        public int getUniqueNumber() {
            return delegate.getUniqueNumber();
        }
    }

}