Java tutorial
/* * Licensed to CRATE Technology GmbH ("Crate") under one or more contributor * license agreements. See the NOTICE file distributed with this work for * additional information regarding copyright ownership. Crate licenses * this file to you under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. You may * obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * * However, if you have executed another commercial license agreement * with Crate these terms will supersede the license and you may use the * software solely pursuant to the terms of the relevant commercial agreement. */ package io.crate.operation.reference.sys; import com.google.common.base.Function; import com.google.common.collect.Maps; import io.crate.metadata.ReferenceImplementation; import io.crate.metadata.SimpleObjectExpression; import io.crate.operation.reference.NestedObjectExpression; import org.apache.lucene.util.BytesRef; import javax.annotation.Nullable; import java.util.List; import java.util.Map; public abstract class SysObjectArrayReference extends SimpleObjectExpression<Object[]> { protected abstract List<NestedObjectExpression> getChildImplementations(); @Override public ReferenceImplementation<Object[]> getChildImplementation(String name) { List<NestedObjectExpression> childImplementations = getChildImplementations(); final Object[] values = new Object[childImplementations.size()]; int i = 0; for (NestedObjectExpression sysObjectReference : childImplementations) { ReferenceImplementation<?> child = sysObjectReference.getChildImplementation(name); if (child != null) { Object value = child.value(); values[i++] = value; } else { values[i++] = null; } } return new SimpleObjectExpression<Object[]>() { @Override public Object[] value() { return values; } }; } @Override public Object[] value() { List<NestedObjectExpression> childImplementations = getChildImplementations(); Object[] values = new Object[childImplementations.size()]; int i = 0; for (NestedObjectExpression expression : childImplementations) { Map<String, Object> map = Maps.transformValues(expression.getChildImplementations(), new Function<ReferenceImplementation, Object>() { @Nullable @Override public Object apply(@Nullable ReferenceImplementation input) { Object value = input.value(); if (value != null && value instanceof BytesRef) { return ((BytesRef) value).utf8ToString(); } else { return value; } } }); values[i++] = map; } return values; } }