/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.
*/
package org.apache.pig.impl.plan;
import java.io.PrintStream;
import java.util.LinkedList;
import java.util.Collection;
import org.apache.pig.impl.util.MultiMap;
/**
* This class dumps a nested plan to a print stream. It does not walk
* the graph in any particular fashion it merely iterates over all
* operators and edges and calls a corresponding dump function. If a
* node of the plan has nested plans this will be dumped when the
* node is handled.
*/
public class PlanDumper<E extends Operator,
P extends OperatorPlan<E>,
S extends OperatorPlan<? extends Operator>> {
protected PrintStream ps;
protected P plan;
protected boolean isVerbose = true;
public PlanDumper(P plan, PrintStream ps) {
this.plan = plan;
this.ps = ps;
}
public void setVerbose(boolean verbose) {
this.isVerbose = verbose;
}
public boolean isVerbose() {
return isVerbose;
}
/**
* This is the public interface. Dump writes the plan and nested
* plans to the stream.
*/
public void dump() {
for (E op: plan) {
MultiMap<E,S> map = getMultiInputNestedPlans(op);
if (isVerbose && !map.isEmpty()) {
dumpMultiInputNestedOperator(op, map);
continue;
}
Collection<S> plans = getMultiOutputNestedPlans(op);
if (plans.size() > 0) {
dumpMultiOutputNestedOperator(op, plans);
continue;
}
plans = getNestedPlans(op);
if (isVerbose && plans.size() > 0) {
dumpNestedOperator(op, plans);
continue;
}
dumpOperator(op);
}
for(E op: plan) {
Collection<E> successors = plan.getSuccessors(op);
if (successors != null) {
for (E suc: successors) {
dumpEdge(op, suc);
}
}
}
}
/**
* makeDumper is a factory method. Used by subclasses to specify
* what dumper should handle the nested plan.
* @param plan Plan that the new dumper should handle
* @return the dumper for plan
*/
@SuppressWarnings("unchecked")
protected PlanDumper makeDumper(S plan, PrintStream ps) {
return new PlanDumper(plan, ps);
}
/**
* Will be called to dump a simple operator
* @param op the operator to be dumped
*/
protected void dumpOperator(E op) {
ps.println(op.name().replace(" ","_"));
}
/**
* Will be called when an operator has nested plans, which are
* connected to one of the multiple inputs.
* @param op the nested operator
* @param plans a map of input operator to connected nested plan
*/
protected void dumpMultiInputNestedOperator(E op, MultiMap<E,S> plans) {
dumpOperator(op);
for (E aop: plans.keySet()) {
for (S plan: plans.get(aop)) {
PlanDumper dumper = makeDumper(plan, ps);
dumper.dump();
}
}
}
/**
* Will be called for nested operators, where the plans represent
* how the output of the operator is processed.
* @param op the nested operator
* @param plans a collection of sub plans.
*/
protected void dumpMultiOutputNestedOperator(E op, Collection<S> plans) {
dumpOperator(op);
for (S plan: plans) {
PlanDumper dumper = makeDumper(plan, ps);
dumper.dump();
for (Operator p: plan.getRoots()) {
dumpEdge(op, p);
}
}
}
/**
* Will be called for nested operators. The operators are not
* specifically connected to any input or output operators of E
* @param op the nested operator
* @param plans a collection of sub plans.
*/
protected void dumpNestedOperator(E op, Collection<S> plans) {
dumpOperator(op);
for (S plan: plans) {
PlanDumper dumper = makeDumper(plan, ps);
dumper.dump();
}
}
/**
* Will be called to dump the edges of the plan. Each edge results
* in one call.
* @param op tail of the edge
* @param suc head of the edge
*/
protected void dumpEdge(Operator op, Operator suc) {
ps.println(op.name()+" -> "+suc.name());
}
/**
* Used to determine if an operator has nested plans, which are
* connected to specific input operators.
* @param op operator
* @return Map describing the input to nested plan relationship.
*/
protected MultiMap<E, S> getMultiInputNestedPlans(E op) {
return new MultiMap<E, S>();
}
/**
* Used to determine if an operator has nested output plans
*
* @param op operator
* @return Map describing the input to nested plan relationship.
*/
protected Collection<S> getMultiOutputNestedPlans(E op) {
return new LinkedList<S>();
}
/**
* Used to determine if an operator has nested plans (without
* connections to in- or output operators.
* @param op operator
* @return Collection of nested plans.
*/
protected Collection<S> getNestedPlans(E op) {
return new LinkedList<S>();
}
/**
* Helper function to print a string array.
* @param sep Separator
* @param strings Array to print
*/
protected void join(String sep, String[] strings) {
if (strings == null) {
return;
}
for (int i = 0; i < strings.length; ++i) {
if (i != 0) {
ps.print(sep);
}
ps.print(strings[i]);
}
}
}