com.tangosol.util.extractor.ReflectionExtractor Maven / Gradle / Ivy
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/*
* Copyright (c) 2000, 2022, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* https://oss.oracle.com/licenses/upl.
*/
package com.tangosol.util.extractor;
import com.oracle.coherence.common.internal.util.CanonicalNames;
import com.tangosol.io.ExternalizableLite;
import com.tangosol.io.pof.PofReader;
import com.tangosol.io.pof.PofWriter;
import com.tangosol.io.pof.PortableObject;
import com.tangosol.util.Base;
import com.tangosol.util.ClassHelper;
import com.tangosol.util.ValueExtractor;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.NotActiveException;
import java.lang.reflect.Method;
import jakarta.json.bind.annotation.JsonbProperty;
/**
* Reflection-based ValueExtractor implementation.
*
* @author cp/gg 2002.11.01, ew 2007.02.01, jf 2016.08.11
*
* @see ChainedExtractor
*/
public class ReflectionExtractor
extends AbstractExtractor
implements ValueExtractor, ExternalizableLite, PortableObject
{
// ----- constructors ---------------------------------------------------
/**
* Default constructor (necessary for the ExternalizableLite interface).
*/
public ReflectionExtractor()
{
}
/**
* Construct a ReflectionExtractor based on a method name.
*
* @param sMethod the name of the method to invoke via reflection
*/
public ReflectionExtractor(String sMethod)
{
this(sMethod, null, VALUE);
}
/**
* Construct a ReflectionExtractor based on a method name and optional
* parameters.
*
* @param sMethod the name of the method to invoke via reflection
* @param aoParam the array of arguments to be used in the method
* invocation; may be {@code null}
*
* @since Coherence 3.3
*/
public ReflectionExtractor(String sMethod, Object[] aoParam)
{
this(sMethod, aoParam, VALUE);
}
/**
* Construct a ReflectionExtractor based on a method name, optional
* parameters and the entry extraction target.
*
* @param sMethod the name of the method to invoke via reflection
* @param aoParam the array of arguments to be used in the method
* invocation; may be {@code null}
* @param nTarget one of the {@link #VALUE} or {@link #KEY} values
*
* @since Coherence 3.5
*/
public ReflectionExtractor(String sMethod, Object[] aoParam, int nTarget)
{
azzert(sMethod != null);
m_sMethod = sMethod;
m_aoParam = aoParam;
m_nTarget = nTarget;
}
// ----- ValueExtractor interface ---------------------------------------
/**
* Extract from target using reflection.
*
* @param oTarget the target
*
* @return value extracted from target
*/
@SuppressWarnings("unchecked")
@Override
public E extract(T oTarget)
{
if (oTarget == null)
{
return null;
}
Class clz = oTarget.getClass();
try
{
Method method = m_methodPrev;
if (method == null || method.getDeclaringClass() != clz)
{
if (!ClassHelper.isReflectionAllowed(oTarget))
{
throw new IllegalArgumentException(suggestExtractFailureCause(clz, true));
}
m_methodPrev = method = ClassHelper.findMethod(
clz, getMethodName(), ClassHelper.getClassArray(m_aoParam), false);
}
//noinspection ConstantConditions
return (E) method.invoke(oTarget, m_aoParam);
}
catch (NullPointerException e)
{
throw new RuntimeException(suggestExtractFailureCause(clz, false));
}
catch (Exception e)
{
throw ensureRuntimeException(e,
clz.getName() + this + '(' + oTarget +')');
}
}
@Override
public String getCanonicalName()
{
String sCName = super.getCanonicalName();
if (sCName == null)
{
sCName = m_sNameCanon = computeCanonicalName(m_sMethod, m_aoParam);
}
return sCName;
}
// ----- Object methods -------------------------------------------------
/**
* Compare the ReflectionExtractor with another object to determine equality.
*
* {@link AbstractExtractor#equals(Object)} contract takes precedence when applicable,
* falling back to implementation specific equals.
*
* Two ReflectionExtractor objects, re1 and re2 are considered
* equal iff re1.extract(o) equals re2.extract(o) for
* all values of o.
*
* @return true iff this ReflectionExtractor and the passed object are
* equivalent
*/
@Override
public boolean equals(Object o)
{
// the super.equals() uses the canonical name comparison (if applies);
// if that succeeds, no other checks are to be made.
if (super.equals(o))
{
return true;
}
else if (isCanonicallyEquatable(o))
{
return false;
}
if (o instanceof ReflectionExtractor)
{
ReflectionExtractor that = (ReflectionExtractor) o;
return this.m_nTarget == that.m_nTarget &&
Base.equals(m_sMethod, that.m_sMethod) &&
equalsDeep(this.m_aoParam, that.m_aoParam);
}
return false;
}
/**
* HashCode value is hashCode of non-null {@link ValueExtractor#getCanonicalName() canonical name};
* otherwise, it is the hashCode of sName passed to {#link ReflectionExtractor(String)}.
*
* @return an integer hash value for this ReflectionExtractor object
*/
@Override
public int hashCode()
{
String sCName = getCanonicalName();
return sCName == null ? m_sMethod.hashCode(): sCName.hashCode();
}
/**
* Provide a human-readable description of this ReflectionExtractor object.
*
* @return a human-readable description of this ReflectionExtractor object
*/
@Override
public String toString()
{
Object[] aoParam = m_aoParam;
int cParams = aoParam == null ? 0 : aoParam.length;
Method methodPrev = m_methodPrev;
String sName = methodPrev == null ? m_sMethod : methodPrev.getName();
StringBuilder sb = new StringBuilder();
if (m_nTarget == KEY)
{
sb.append(".getKey()");
}
sb.append('.').append(sName).append('(');
for (int i = 0; i < cParams; i++)
{
if (i != 0)
{
sb.append(", ");
}
sb.append(aoParam[i]);
}
sb.append(')');
return sb.toString();
}
// ----- accessors and helpers ------------------------------------------
/**
* Determine the name of the method that this extractor is configured to
* invoke.
*
* @return method name, property name or key
*/
public String getMethodName()
{
return m_sMethod;
}
/**
* Return the array of arguments used to invoke the method.
*
* @return the array of arguments used to invoke the method
*/
public Object[] getParameters()
{
return m_aoParam;
}
/**
* Return a message suggesting a possible cause for a failure to extract a
* value.
*
* @param clzTarget the target object's class
* @param fFiltered pass {@code true} if the type was an invalid reflection target type
*
* @return the suggested reason for the failure of the extraction
*/
private String suggestExtractFailureCause(Class clzTarget, boolean fFiltered)
{
String sMsg = "Missing or inaccessible method: " +
clzTarget.getName() + this;
if (com.tangosol.util.MapEvent.class.isAssignableFrom(clzTarget))
{
sMsg += " (the object is a com.tangosol.util.MapEvent, which may "
+ "suggest that a raw com.tangosol.util.Filter is "
+ "being used to filter map events rather than a "
+ "com.tangosol.util.filter.MapEventFilter)";
}
if (fFiltered)
{
sMsg += " (The type, " + clzTarget.getName() + ", is disallowed as a reflection target by the current "
+ "reflection filter configuration)";
}
return sMsg;
}
/**
* Compute the canonical name for this extractor.
*
* Steps to compute canonical name from a provided name:
*
* - If parameter aoParam has one or more parameters, the canonical name is null.
* - if name begins with a JavaBean accessor prefixes {@link CanonicalNames#VALUE_EXTRACTOR_BEAN_ACCESSOR_PREFIXES}
* "get" or "is, it is a property. The canonical name is formed by removing that prefix
* and converting the first letter to lowercase.
* - Otherwise, sName is consider a no-arg method and its canonical form
* is the sName with a suffix of "()" appended.
*
*
* The following examples are properties that resolve to the canonical name {@code foo}:
*
* - getFoo
* - getfoo
* - isFoo
* - isfoo
*
*
* A No-arg method name "aMethod" has a canonical name of "aMethod()".
*
* @param sName a method name unless it starts with "get" or "is", then treated as a property
* @param aoParam optional parameters
*
* @return canonical name of sName if it exist; otherwise, {@code null}
*
* @since 12.2.1.4
*/
protected String computeCanonicalName(String sName, Object[] aoParam)
{
String sNameCanonical = null;
int nNameLength = sName == null ? 0 : sName.length();
String [] accessorPrefixes = CanonicalNames.VALUE_EXTRACTOR_BEAN_ACCESSOR_PREFIXES;
if (aoParam == null || aoParam.length == 0)
{
for (int cchPrefix = 0, len = accessorPrefixes.length; cchPrefix < len && sNameCanonical == null; cchPrefix++)
{
int nPrefixLength = accessorPrefixes[cchPrefix].length();
if (nNameLength > nPrefixLength && nNameLength > 0 && sName.startsWith(accessorPrefixes[cchPrefix]))
{
sNameCanonical = Character.toLowerCase(sName.charAt(nPrefixLength)) +
sName.substring(nPrefixLength + 1);
}
}
if (sNameCanonical == null)
{
// method name with no parameters
sNameCanonical = sName + "()";
}
}
return sNameCanonical;
}
// ----- ExternalizableLite interface -----------------------------------
/**
* {@inheritDoc}
*/
public void readExternal(DataInput in)
throws IOException
{
m_sMethod = readUTF(in);
int cParams = readInt(in);
azzert(cParams < 256, "Unexpected number of method parameters");
Object[] aoParam = cParams == 0 ? null : new Object[cParams];
for (int i = 0; i < cParams; i++)
{
aoParam[i] = readObject(in);
}
m_aoParam = aoParam;
m_nTarget = readInt(in);
}
/**
* {@inheritDoc}
*/
public void writeExternal(DataOutput out)
throws IOException
{
String sMethod = m_sMethod;
if (sMethod == null)
{
throw new NotActiveException(
"ReflectionExtractor was constructed without a method name");
}
Object[] aoParam = m_aoParam;
int cParams = aoParam == null ? 0 : aoParam.length;
writeUTF(out, sMethod);
writeInt(out, cParams);
for (int i = 0; i < cParams; i++)
{
writeObject(out, aoParam[i]);
}
writeInt(out, m_nTarget);
}
// ----- PortableObject interface ---------------------------------------
/**
* {@inheritDoc}
*/
public void readExternal(PofReader in)
throws IOException
{
m_sMethod = in.readString(0);
// slot #1 is taken by pre-Coherence 3.5 versions for the number of
// arguments in the parameter array
int cParams = in.readInt(1);
if (cParams > 0)
{
// fully backwards compatible implementation
Object[] aoParam = new Object[cParams];
for (int i = 0; i < cParams; i++)
{
aoParam[i] = in.readObject(i + 2);
}
m_aoParam = aoParam;
}
else
{
// slot #2 is used @since Coherence 3.5 to store the entirety
// of the arguments (as opposed to the first of the arguments)
m_aoParam = in.readArray(2, Object[]::new);
m_nTarget = in.readInt(3);
}
}
/**
* {@inheritDoc}
*/
public void writeExternal(PofWriter out)
throws IOException
{
String sMethod = m_sMethod;
if (sMethod == null)
{
throw new NotActiveException(
"ReflectionExtractor was constructed without a method name");
}
out.writeString(0, sMethod);
// slot #1 is not used @since Coherence 3.5
out.writeObjectArray(2, m_aoParam);
out.writeInt(3, m_nTarget);
}
// ----- data members ---------------------------------------------------
/**
* The name of the method to invoke.
*/
@JsonbProperty("method")
protected String m_sMethod;
/**
* The parameter array.
*/
@JsonbProperty("args")
protected Object[] m_aoParam;
/**
* A cached reflection method (to avoid repetitive look-ups).
*/
private transient Method m_methodPrev;
}