Android Open Source - DKO Filtering Query

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License

The source code is released under:

GNU Lesser General Public License

Java Source Code

package org.kered.dko;
//from ww w.ja  v a 2 s  . c o  m
import java.sql.Connection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.sql.DataSource;

import org.kered.dko.Constants.DB_TYPE;
import org.kered.dko.Constants.DIRECTION;
import org.kered.dko.Field.FK;

class FilteringQuery<T extends Table> extends AbstractQuery<T> implements MatryoshkaQuery<T> {

  private Query<T> q;
  private Condition condition = null;
  private long top = -1;

  FilteringQuery(final FilteringQuery<T> src) {
    super(src.getType());
    this.q = src.q;
    this.condition = src.condition;
    this.top = src.top;
  }

  FilteringQuery(final Query<T> q, final Condition... conditions) {
    super(q);
    this.q = q;
    if (conditions==null || conditions.length==0) return;
    condition = conditions[0];
    if (conditions.length>1) {
      Condition[] c2 = new Condition[conditions.length-1];
      System.arraycopy(conditions, 1, c2, 0, conditions.length-1);
      condition = condition.and(c2);
    }
  }

  @Override
  public Query<T> where(final Condition... conditions) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    if (condition==null) {
      condition = conditions[0];
      if (conditions.length>1) {
        Condition[] c2 = new Condition[conditions.length-1];
        System.arraycopy(conditions, 1, c2, 0, conditions.length-1);
        condition = condition.and(c2);
      }
    } else {
      this.condition = this.condition.and(conditions);
    }
    return ret;
  }

  @Override
  public Query<T> limit(long n) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.limit(-1);
    ret.top = n;
    return ret;
  }

  @Override
  public Query<T> distinct() {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.distinct();
    return ret;
  }

  @Override
  public Query<T> avg() {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.avg();
    return ret;
  }

  @Override
  public Query<T> max() {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.max();
    return ret;
  }

  @Override
  public Query<T> min() {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.min();
    return ret;
  }

  @Override
  public Query<T> with(FK... fields) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.with(fields);
    return ret;
  }

  @Override
  public Query<T> deferFields(Field<?>... fields) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.deferFields(fields);
    return ret;
  }

  @Override
  public Query<T> deferFields(Collection<Field<?>> fields) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.deferFields(fields);
    return ret;
  }

  @Override
  public Query<T> onlyFields(Collection<Field<?>> fields) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.onlyFields(fields);
    return ret;
  }

  @Override
  public Query<T> onlyFields(Field<?>... fields) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.onlyFields(fields);
    return ret;
  }

  @Override
  public Query<T> set(Field<?> key, Object value) {
    throw new IllegalStateException("this is a read-only query");
  }

  @Override
  public Query<T> set(Map<Field<?>, Object> values) {
    throw new IllegalStateException("this is a read-only query");
  }

  @Override
  public Query<T> use(DataSource ds) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.use(ds);
    return ret;
  }

  @Override
  public Query<T> use(Connection conn) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.use(conn);
    return ret;
  }

  @Override
  public Query<T> use(DB_TYPE type) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.use(type);
    return ret;
  }

  @Override
  public Query<T> in(Collection<T> set) {
    // TODO Auto-generated method stub
    return null;
  }

  @Override
  public DataSource getDataSource() {
    return q.getDataSource();
  }

  @Override
  public List<Field<?>> getSelectFields() {
    return q.getSelectFields();
  }

  @Override
  public Iterator<T> iterator() {
    return new Iterator<T>() {

      final Iterator<T> i = q.iterator();
      T next = null;
      int count = 0;

      @Override
      public boolean hasNext() {
        if (next!=null) return true;
        if (top > -1 && count >= top) return false;
        while (i.hasNext()) {
          T candidate = i.next();
          if (condition.matches(candidate)) {
            next = candidate;
            return true;
          }
        }
        return false;
      }

      @Override
      public T next() {
        T ret = next;
        next = null;
        ++count;
        return ret;
      }

      @Override
      public void remove() {
        i.remove();
      }
    };
  }

  @Override
  public Collection<Query<? extends Table>> getUnderlying() {
    Collection<Query<? extends Table>> ret = new ArrayList();
    ret.add(q);
    return ret;
  }

  @Override
  public Query<T> orderBy(Expression.OrderBy<?>... obes) {
    FilteringQuery<T> ret = new FilteringQuery<T>(this);
    ret.q = ret.q.orderBy(obes);
    return ret;
  }

}

Java Source Code List

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